Getting to know an old truck: identifying parts on her.

[thelawdoc]

Guys, I recently acquired my '65-'66 Chevy C10 250 I6. I have her manuals and I have the other books that everyone uses. What I do not have is any of her history or specific info from the previous owners. Since I am contemplating various R&R projects, I think that I should at least know what I have at the moment. It seems that I need to assume that little or nothing that I have today is going to be exactly what was shipped out by Chevrolet in 1966. My problem is that I am a novice/wannabe mechanic and therefore cannot give a quick look at a part and know what type, model, etc., it may be. Many hours online has not been as productive as I had hoped. As much as I hate coming to a forum with photos and asking members to guess as to what I have, I am getting desperate. With my hope that I be indulged, I am attaching below some photos. If anyone can give me a lead about the parts from the photos, I would be grateful. Essentially, I just want to know 'what I have.' I will then do my research about it. Note that my truck is a daily driver, street use truck. Mileage is the name of the game, not performance.

1. Carburetor. Anyone recognize which company? It is a rebuild, of course, and it works fine -though I do have to take it out and give it a damn good cleaning so that I can stop depending on carb cleaner. My plans are to buy a new single barrel or maybe progressive 2 barrel. But I need an idiot's carburetor that I can adjust myself, clean myself, and rebuild myself if I live that long. I will buy a new one once I can figure out the cfm that my engine calls for. Also need to decide whether I want an electric choke.

2. Distributor. Looks to me to be a 'standard' type. My plans are to go to a DUI or similar upgrade, and HEI. I need my truck to start up in northern cold climates.

3. Valve cover: I need to know whether I have an "early small log" or "late big log" -or something else, in order to use the formula to determine the cfm that I need from a new carb. Without knowing my needed cfm, I cannot buy a carb. It might help if I even knew what a 'log' was.

I have spent a lot of time considering what to do for my engine. All I need and want is a daily, comfortable driver. Nothing showy. Nothing for a get-a-way car. I have to use my money prudently. Very prudently. And I have do the work myself, not because I am competent to or want to. Rather, because I have to. (One must make do with what one has.) Brakes I won't permit myself to mess with yet. I will give her to a shop and be rid of the single pot and I will split the front drums from the rear drums. And she needs a bolt-on overdrive when a few grand find my wallet. Anyway, thanks guys.
-Alden

[1963c-10]

Your engine looks pretty stock, minus the air cleaner. The carb is a Rochester model B. Was a common carb used by Chevy on the 230 & 250 engines, and maybe some others. Very simple (maybe 40 parts in total) and reliable carbs, but they are prone to leaking between the upper and lower bowls and not the best for fuel economy. The valve cover is also stock for the 230, 250 and 292 and will not hinder any other carb you decide to install with it. There are multiple threads on various carbs for your engine. HEI's are made for the inline 6 and a pretty easy swap. I did a pertronix II ignition in my 63 when I had the 230, with no issues....but if I had to do it again....I'd drop a true HEI in there.

Great link on upgraded 6 cyls: http://67-72chevytrucks.com/vboard/s...d.php?t=276823

Also check through the FAQ's section......tons and tons of great info on these old trucks: http://67-72chevytrucks.com/vboard/s...d.php?t=559678

[thelawdoc]

1963c10, thanks! Much appreciated. And, yes, I have been spending time at the FAQ section. Living there almost. It is the best. What do you mean when you say "a true HEI?" Also, for purposes of calculating cfm needed in a carb, would you say that I have an 'early small log' (as opposed to a 'late big log')? -Alden

[1963c-10]

You have a points distributor, the pertronix is an electronic upgrade that replaces the points, but is not a true hei. It conceals under the dist cap. There are true "hei" distributors available. Thats what I would use if I did it again.

Normally I see 390cfm carbs on modified 6's, and a 1-2 barrel is the norm. If your engine ia stock, then a stock carb or a smaller 2bbl should suffice. I dont know what the early/late log deal is...never heard of it.

They are fairly easy engines and for a solid driver, normal tune up, and the ignition upgrade will make a solid truck. If cost is a factor, rebuild the rochester. With carb swaps, you'll have linkage to purchase or modify.

[thelawdoc]

1963c-10, thank you. I have made good note of all that you said.
I ran across cylinder head log size when I was researching carbs at Classic Inlines: http://www.classicinlines.com/CarbChoice.asp I never heard of log size aside from that site. On that page, there is a chart that advises cfm based, in part, on cylinder head type. For my 250 stock street engine, they recommend a carb with 255-265 cfm -if I have a small early log; 295-320 cfm if I have a late large log or a converted log; and other cfm's if I have any of the other cylinder head types on their chart. I think I can assume that I have an early small log cylinder head. I appreciate your help today. -Alden

[66Submarine]

For one thing, that looks to be a Ford six website. I'll also add that I've never heard of (or even understand) the "log" thing; may be some stupid Ford lingo.

You just want a replacement stock carb (Monojet or model B) or (pretty much) the smallest 2/4 barrel you can come up with; not a lot of air going through a little 250 under normal driving conditions.

You have the stock points distributor; I personally don't have much of an issue with points (that's what all my stuff has as of now). "Real" HEI means a GM unit; they have a much larger diameter cap (some have the coil in the cap, and some have remote coils).

The factory OD three speed transmissions turn up every once in a while, and usually seem to be pretty cheap.

[thelawdoc]

66Submarine, thank you. I was thinking that 'log' must be some kind of lingo. But when one is as green as I am, it is easy to be stumped. All in all, I was trying to do the right thing by matching cfm between carb and engine. I will make note that 260 cfm should be fine for my purposes. I have no intentions of any major performance mods on my inline six aside from the HEI set.

I did, up until recently, consider changing my tranny for one with an overdrive. I was sort of 'saving up' for that. But my powerglide did not make it and I ended up having to do an unexpected rebuild. Now I figure I will keep the PG since she is under a 12k mile warranty and I will probably not do much freeway driving anymore. I am packing for retirement to the northern woods. The average excursion for me will likely be to a Walmart or Lowe's within 25 miles. It is time for the kids to come to me now when they want to see me. They have nice computerized cars that get high mpg and are comfy enough for the 12 hour drive, lol. Thanks guy. -Alden

[66Submarine]

Oh, sorry; momentarily forgot all about the PG thing somehow! Not sure how I managed to do that and plug column shift three speed in there...

Yeah, any small carb should work; for something like you are describing, I'd much rather have a "too small" carb than a big one! Any particular reason that you're changing carbs, anyway? I've had pretty good luck with at least the Monojets (haven't run the older model B yet to test fuel economy).

I actually have one of the little progressive 2bbl Weber carbs, but I haven't tried it out yet; need to finally do that one of these days...

[thelawdoc]

66Submarine, Yeah, I did not remind you about my PG saga so that I would not be reminded myself! Wasn't that a nightmare? As for my carb, it is more a matter of peace of mind. When I acquired the truck last January the previous owner said the carb had been rebuilt 'recently.' Maybe it was, maybe it wasn't. And if rebuilt, where, by whom, and with whose kit? I am getting terrible mgp. It may even be that I, myself, am to blame, having let the truck sit from January to April. Fuel goes to varnish, etc. Who knows. In recent days, ever since getting my tranny back up to snuff, the truck has some hesitation, a stall here and there, she smells of gas under the hood, the carb seems to be flooding, making for tedious, difficult starts, fouled plugs, etc. At first I thought it was me, choking her too much when starting, but I am suspecting that one or more things are amiss inside. Who knows. My carb is a part that I want to know inside and out. I want to verify not just that the check balls are all there, but that the correct size check balls are there. I want to check the throttle shaft wear myself and be sure that fuel does not leak through the bushing. The needle. The jets. Whatever I can check. I have not made a final decision to swap my Rochester B yet. Tomorrow I want to bring it into the house and give it a good medical on the kitchen table under good light with my glasses on my nose. Clean her up a bit. A little pampering. Verify that I don't have to rebuild her. Then, if the Roch B is amenable to a HEI that I plan on in the near future, I will keep her. Thanks for responding. -Alden

[TJ's Chevy]

Well..to be honest...there's no specific CFM rate that 250 calls for. Mildy modified 250's have had 600 CFM edelbrocks bolted on.....Know a guy who bolted a 600 Holley to a stock 250 (Not that its recommended). I've seen supercharged 250's with Dual 1050 demond carbs. They're really is no perfect carb setup for these engines....I mean...a 500 edelbrock is gonna perform nearly the same as a 600 on a 250..why? Its over carbed anyway..and 100 cfm doesn't make much of a difference. 390 holleys are over priced and only come with the electric choke option..plus holley has a bad reputation of having nasal leaks after so many miles of use. Issue with edelbrock is they hate heat. And webers can be a pain in the ****** to tune. So...no carb is really perfect. So if your dead on staying stock except for an HEI upgrade..then a 2 barrel holley 350 or 500 cfm or weber 32/36 is your best choice. Unless your gonna upgrade to a clifford intake and headers then a small 4 barrel will work...a 500 edelbrock Will work outta the box on a 250, but it never hurts to jet it down a step or two...and so will a 390 holley if you have money to waste. The valve cover has nothing to do with the CFM called for on the carb....from 63-68 I believe the valve cover was the same...in the later years they're was a tiny almost unnoticeable change. But if your staying stock...then a new single barrel carb from Autozone will work...its a newer series that supposedly works better...has for me when I bought one for one of my 292's.

[thelawdoc]

T.J., Thank you for responding. I have been spending some time trying to find out what cfm my 250 calls for. At some point in the last few months, it got into my head that the carb and engine ought to be matched up for cfm. Going through my notes (I am learning all of this on my own) I do not see where I got this from. Choice of carb has become somewhat of a chore for a guy like me, who has no lifetime of experience, to decide on my own. I have by now spent what is perhaps an inordinate amount of time researching carbs -and I am beginning to go in circles. I don't have any particular bias against my Roch B -so long as it will be ok with an HEI that I want in the near future. I have no obsessive need to stay stock, just financial considerations. But I am particular about having a carb that is reliable and easy to maintain or rebuild. My Roch B seems fine in the latter category. I am not sure about the reliability. I just don't have enough miles with it under my belt to decide on my own. I tend to think that the Roch B should be fine for me since I got this truck from a guy who was an automotive techie for most of his life. But he had the truck in Florida and I will be running her in Maine -a very different climate for the Roch B. -Alden

[ACK]

Just my recommendation:

1. If you like puzzles, rebuild the carb. It's cheap, easy, and you'll learn the basics of how it works

2. Upgrade to an HEI for better performance and reliability. Once installed, you can increase your timing to get more HP and maybe better mileage.

3. If you still have an externally regulated alternator, replace it with an internally regulated one with more amps.

4. Without a doubt, do the headlight relay upgrade

5. If and when you replace the carb, the Weber 32/36 appears to offer a lot of bang for the buck


Once you complete items 1 - 4, I'll bet you'll feel a lot more comfortable working on your truck. Good luck and keep us updated.

[thelawdoc]

Ack, thank you for your comments. I actually enjoy sitting in the kitchen and cleaning up a carb. It's therapeutic. If the lady of the house is not around, it is also safe. The recommendations I got seem to bring me down to either a Weber 32/36 or the Autozone 1945. Seems to me that either should be good for me and a bit better than my Roch B. If I retire the Roch B, it will just be a matter of which one is easier for a novice to get along with. The Weber, at first blush, seems to be more easily managed by one with more experience than I have, but I am not intimidated. I have come to understand that if one wants to run a vintage truck, one has to at least put some time in to getting perfectly familiar with the carb. My dad used to tear down and clean his carb pretty often, I think like 3 times a year. He did not like to wait for symptoms or surprises. An HEI is definitely on my list. But it is something that I will have to do myself (due to budget constraints) when I can go for a few days without needing the truck. (What takes you guys an hour, takes me 5!) And the alternator/ext. reg. is slated to go, too. I have my eye on a Delco 12SI 94 amp but I do not believe there are any new ones available nowadays. I trust a company called MAD and if they have one I will take it from them. As for relays, yes, I am a believer. The more the merrier. I go for Bosch because I trust the name. Thanks, guys. It is humbling to receive the attention that the people in this forum give. Really. -Alden

[66Submarine]

Originally Posted by T.J. MCCAULEY

Well..to be honest...there's no specific CFM rate that 250 calls for. Mildy modified 250's have had 600 CFM edelbrocks bolted on.....Know a guy who bolted a 600 Holley to a stock 250 (Not that its recommended). I've seen supercharged 250's with Dual 1050 demond carbs. They're really is no perfect carb setup for these engines....I mean...a 500 edelbrock is gonna perform nearly the same as a 600 on a 250..why? Its over carbed anyway..and 100 cfm doesn't make much of a difference. 390 holleys are over priced and only come with the electric choke option..plus holley has a bad reputation of having nasal leaks after so many miles of use. Issue with edelbrock is they hate heat. And webers can be a pain in the ****** to tune. So...no carb is really perfect. So if your dead on staying stock except for an HEI upgrade..then a 2 barrel holley 350 or 500 cfm or weber 32/36 is your best choice. Unless your gonna upgrade to a clifford intake and headers then a small 4 barrel will work...a 500 edelbrock Will work outta the box on a 250, but it never hurts to jet it down a step or two...and so will a 390 holley if you have money to waste. The valve cover has nothing to do with the CFM called for on the carb....from 63-68 I believe the valve cover was the same...in the later years they're was a tiny almost unnoticeable change. But if your staying stock...then a new single barrel carb from Autozone will work...its a newer series that supposedly works better...has for me when I bought one for one of my 292's.

Dear God, did some chucklehead really put TWO 1050's on a 250?!?! I can't imagine how that must have ran...

Any pictures/video?

[66Submarine]

Originally Posted by thelawdoc

As for my carb, it is more a matter of peace of mind. When I acquired the truck last January the previous owner said the carb had been rebuilt 'recently.' Maybe it was, maybe it wasn't. And if rebuilt, where, by whom, and with whose kit? I am getting terrible mgp. It may even be that I, myself, am to blame, having let the truck sit from January to April. Fuel goes to varnish, etc. Who knows. In recent days, ever since getting my tranny back up to snuff, the truck has some hesitation, a stall here and there, she smells of gas under the hood, the carb seems to be flooding, making for tedious, difficult starts, fouled plugs, etc. At first I thought it was me, choking her too much when starting, but I am suspecting that one or more things are amiss inside. Who knows. My carb is a part that I want to know inside and out. I want to verify not just that the check balls are all there, but that the correct size check balls are there. I want to check the throttle shaft wear myself and be sure that fuel does not leak through the bushing. The needle. The jets. Whatever I can check. I have not made a final decision to swap my Rochester B yet. Tomorrow I want to bring it into the house and give it a good medical on the kitchen table under good light with my glasses on my nose. Clean her up a bit. A little pampering. Verify that I don't have to rebuild her. Then, if the Roch B is amenable to a HEI that I plan on in the near future, I will keep her. Thanks for responding. -Alden

Yeah, that's what I figured; sounds like you have fuel coming past the needle and seat for whatever reason. Look at the tailpipe when it starts to die and you have to stab the throttle; you'll probably see a puff of black smoke from all the excess fuel. You might also want to check the fuel pressure and make sure it's not the culprit (or making it worse).

Any carb will work fine with the HEI--it's just a distributor with a little hotter spark and without the points to adjust/wear.

BTW, here's a plug from my 250 with a Monojet, FWIW.

[thelawdoc]

66Submarine, thanks. To my eye, your plug reads as it should be, i.e., tan tinge. I am too embarrassed to show what my plugs looked like when I took them out the other day. People go to jail for possessing what I had. Yesterday, she started up only with carb cleaner. And maybe I used too much- she backfired after idling smoothly for about half a minute. That gave me a good 'start' too, and certainly woke up a few who reside in the local cemetary! No big deal- this weekend I will have a good look at every piece of my carb and verify correct fuel pressure. I also see that I am missing the bronze filter that sits at the entrance to the Roch B. This whole starting issue came out of nowhere just a few days ago. I want to nip it in the bud. I am slated to hit the road for a 12 hour drive to Maine next week. She's a rascal. But I love her. -Alden

[TJ's Chevy]

Originally Posted by 66Submarine

Dear God, did some chucklehead really put TWO 1050's on a 250?!?! I can't imagine how that must have ran...

Any pictures/video?

Well...considering it was a Drag car...and it was supercharged....I'm sure it had some camshaft mods and head work done. lol Well....I wouldn't consider him a chucklehead....but more like an experienced I6 racer.

[66Submarine]

Originally Posted by thelawdoc

66Submarine, thanks. To my eye, your plug reads as it should be, i.e., tan tinge. I am too embarrassed to show what my plugs looked like when I took them out the other day. People go to jail for possessing what I had. Yesterday, she started up only with carb cleaner. And maybe I used too much- she backfired after idling smoothly for about half a minute. That gave me a good 'start' too, and certainly woke up a few who reside in the local cemetary! No big deal- this weekend I will have a good look at every piece of my carb and verify correct fuel pressure. I also see that I am missing the bronze filter that sits at the entrance to the Roch B. This whole starting issue came out of nowhere just a few days ago. I want to nip it in the bud. I am slated to hit the road for a 12 hour drive to Maine next week. She's a rascal. But I love her. -Alden

Yeah, the plugs look good in this one; that's what you're looking to see when everything's working as it should.

Might not even be anything wrong with the carb if you don't have any filter on it; without a filter, small particles can potentially get stuck in the needle and seat and hold it partially open.

I'd also personally much rather have a paper filter element instead of the sintered bronze rock, but I don't know the correct part number for one at the moment.

BTW, the fuel pressure should be about 3 to 4.5PSI per GM spec.

[66Submarine]

Originally Posted by T.J. MCCAULEY

Well...considering it was a Drag car...and it was supercharged....I'm sure it had some camshaft mods and head work done. lol Well....I wouldn't consider him a chucklehead....but more like an experienced I6 racer.

How much HP? Generally, you'd see twin 1050's on something like a 1,000HP 572BBC; it would need to be one hell of a 250 to actually want that, much less need it.

[thelawdoc]

66Submarine, Actually I did note that the bronze filter was missing some time ago but I was not alarmed because I thought that the inline paper filter was sufficient. At the same time, I was wondering why the Chevy engineers put such a filter there if they had already put other filters in the fuel line. Personally, I prefer to give much deference to engineers unless they be shown to be mistaken by overwhelming empirical evidence from enthusiasts. I have tried to research the bronze filter 'issue,' and while there seems to be plenty of discussion about it in forums, along with ample and vigorous differences of opinion, I have yet to come upon any technically supported position one way or the other. While I will certainly keep this issue in the back of mind, I will do the following for my truck in the meantime: maintain the sock filter in the tank; maintain an extra large paper filter inline before the pump; maintain another inline paper filter after the pump; and maintain the sintered bronze filter at the carb. I will verify that I have my 3.5 -4.5 psi going into the bronze filter as per the manual. I am really not concerned that the bronze filter might cause some minimal reduction of psi. For one thing, the manual's spec permits for a full pound in range of psi; and secondly, the empirical evidence has it that the Roch B is flood prone. I notice that the manual has a lot of instruction for the Roch B. I have to digest that material, put my Roch B in the condition called for by the manual, and then see where things are at. I am pretty sure that my starting/mpg issues come from my carb, so it is now up to me to resolve them. I have the manual. I have a screw driver and I have you guys here. It will get done. -Alden

[66Submarine]

Originally Posted by thelawdoc

66Submarine, Actually I did note that the bronze filter was missing some time ago but I was not alarmed because I thought that the inline paper filter was sufficient. At the same time, I was wondering why the Chevy engineers put such a filter there if they had already put other filters in the fuel line. Personally, I prefer to give much deference to engineers unless they be shown to be mistaken by overwhelming empirical evidence from enthusiasts. I have tried to research the bronze filter 'issue,' and while there seems to be plenty of discussion about it in forums, along with ample and vigorous differences of opinion, I have yet to come upon any technically supported position one way or the other. While I will certainly keep this issue in the back of mind, I will do the following for my truck in the meantime: maintain the sock filter in the tank; maintain an extra large paper filter inline before the pump; maintain another inline paper filter after the pump; and maintain the sintered bronze filter at the carb. I will verify that I have my 3.5 -4.5 psi going into the bronze filter as per the manual. I am really not concerned that the bronze filter might cause some minimal reduction of psi. For one thing, the manual's spec permits for a full pound in range of psi; and secondly, the empirical evidence has it that the Roch B is flood prone. I notice that the manual has a lot of instruction for the Roch B. I have to digest that material, put my Roch B in the condition called for by the manual, and then see where things are at. I am pretty sure that my starting/mpg issues come from my carb, so it is now up to me to resolve them. I have the manual. I have a screw driver and I have you guys here. It will get done. -Alden

GM only had the mesh filter sock in the tank and the little one in the carb inlet. If you have a good inline filter in the line, the only stuff that really can get to the carb (besides really fine stuff IME) is whatever comes from the last part of the line itself (or pump if it's before the pump), so I wouldn't personally worry too much about it.

The sintered bronze rock filters had a reputation for plugging up without really looking like it (kind of hard to tell), where it's much more obvious with the paper filter; they also made some with a fine plastic mesh screen element (I have one).

The spec I have says 3 to 4.5PSI for most years, and IME your problem will almost always be too much pressure, not too little (my current truck had a little over 5PSI when I put a gauge on it the other day).

[thelawdoc]

66Submarine, for some time I did not know that the carb intake takes such a filter. As a novice, I was looking around in the parts stores for some paper filter that might fit. It is interesting to note that the filter is rather inexpensive -just a few dollars. I have sintered bronze bearings on my Atlas lathe. They cost around $50, if I recall correctly, even though they have much less material. If I ever find the time, I shall have to try making some bearings from the filters. Of course it is hard to see such a filter when it is full. The filter is working on much finer refuse. But Chevy matched that filter to my Roch B, obviously with deference to the carb needle valve, so I will continue to do so. Plus, I kinda like those filters. If I had the time, I would make a housing for it such that I could check fuel presssure at a point between that filter and the carb. I suppose those little carb filters, what with being out of sight and giving little or no notice of needing changing, end up being tossed when people break down on the road, and therefore not replaced. A bypass would defeat the purpose of the filter. Far be it from me to try to improve something designed by an engineer, but I will see if there are any off-the-shelf fittings that might permit me to have a dash pressure gauge plug in at the carb entrance. If the gauge be a full-swing style, I should be able to notice that the bronze filter is filling up. A gauge at any other point seems to have useless information. Moreover, I wonder whether a clogging bronze filter might have a damaging effect on the fuel pump's diaphragm or seals. I will try to find a dash panel fuel pressure gauge that has the most sensitivity at a reasonable price. I don't think the carb will care where the gauge sits in the line. -Alden