PROJECT: How would a Chevrolet dealer build a shop truck in the early 1970s?

[DD1]

Originally Posted by mattfranklin

I should have explained better. Ideally you want the rocker arm to push, on average, in the middle of the top of the valve stem. As the valve seats wear and sink the valve stem gets taller and you’d need a longer pushrod to maintain geometry. If the deck of the block or the mating surface of the head are decked or milled you’d need to compensate with shorter push rods. If the engine is old and lots stuff has been done you have no idea which way to go the cool trick is to use a dry-erase pen on top of the valve stem and color it in. Then you assemble things and rotate the engine through four revolutions or so. Then carefully disassemble and see the wear (or witness) marks of where it was contacting. If the wear mark is in the middle you are perfect. If it’s toward the intake manifold then the pushrods are too short. If the wear mark is closer to the exhaust side then the pushrods are too long. In my case I lucked out and stock length was spot on. There are some good videos on that and I think Comp Cams has a PDF of instructions for that.

Thanks for the detailed explanation. It does help me understand what you did much better.

However this will remain in the category of things I "should not attempt at home," and probably for a good reason. I am happy it worked out perfectly for you; my luck is not usually that good.

[mattfranklin]

Intake on and torqued.

[mattfranklin]

Carb, fuel line, and water pump.

[mattfranklin]

And now headers. With Remflex #2006 gaskets to prevent leaks. Highly rated by those that use them. We’ll see if I can screw that up. ;-)

[mattfranklin]

I'm in the middle of trying to get the radiator support rust repaired. I ran across this channel on YouTube. The guy is pretty talented and shares some cool tricks. I'm very surprised there are not more views. Really good info.

Radiator support rust repair:
https://www.youtube.com/watch?v=8I42...RGvLl&index=53
This one I will follow because I bought the Brothers patch kit and his technique will be helpful.
If I'd realized the extent of my rust I might have just bought one, but I'm still happy to save the $200 and do it myself.


Inner fender rust repair:
https://www.youtube.com/watch?v=fjnC...x7fJMEhQl&t=0s
I'm just glad I *didn't* see this one before just buying a new inner right fender. I like to do everything myself, but my time is limited and it's so tempting to take on more. Really cool tricks with the guide pieces and jigs.

[DD1]

Originally Posted by mattfranklin

I'm in the middle of trying to get the radiator support rust repaired. I ran across this channel on YouTube. The guy is pretty talented and shares some cool tricks. I'm very surprised there are not more views. Really good info.

Radiator support rust repair:
https://www.youtube.com/watch?v=8I42...RGvLl&index=53
This one I will follow because I bought the Brothers patch kit and his technique will be helpful.
If I'd realized the extent of my rust I might have just bought one, but I'm still happy to save the $200 and do it myself.


Inner fender rust repair:
https://www.youtube.com/watch?v=fjnC...x7fJMEhQl&t=0s
I'm just glad I *didn't* see this one before just buying a new inner right fender. I like to do everything myself, but my time is limited and it's so tempting to take on more. Really cool tricks with the guide pieces and jigs.

Thanks for sharing. I skipped through the inner fender one. It's interesting. Don't know if I have the time, tools, and patience for it. But it's good to have just in case.

[mattfranklin]

No more painting! Not that any of it is done other than the frame and suspension pieces I've reworked, but I just wanna drive it a little before winter. And I'm tired of painting and looking at rust. Phase two next summer will hit those things.

Two buddies are coming over Saturday to help button up the front end. Hopefully we can get it running so I can at least change its parking spot when needed. :-).

[mattfranklin]

I am so blessed to have good friends who know what they're doing. On Saturday two buddies came over.
We did troubleshooting on brake leaks and got the brakes bled and working well.
Also installed inner and outer fenders.

I still have a list of things to do but Jay and Biju helped me with major things that I couldn't do my myself very well and gave me a big boost in encouragement to keep chipping away at the rest of it.

[DD1]

Originally Posted by mattfranklin

I am so blessed to have good friends who know what they're doing. On Saturday two buddies came over.
We did troubleshooting on brake leaks and got the brakes bled and working well.
Also installed inner and outer fenders.

I still have a list of things to do but Jay and Biju helped me with major things that I couldn't do my myself very well and gave me a big boost in encouragement to keep chipping away at the rest of it.

That's awesome. It's great to have friends you can count on. A buddy of mine helped me get the brake drum hardware done recently; was driving me crazy. Glad it worked out for you.

[mattfranklin]

Just discovered that the water pump weep hole is leaking. Then discovered that this truck has the *long* water pump. The PO did say the motor came from a '78 truck, so they must have taken all of the accessories from the '78, too. I think for now I'll stick with that setup and just buy a long pump to get it running and driving.

I found this thread with some good discussion:
http://67-72chevytrucks.com/vboard/s...d.php?t=436448

[DD1]

Originally Posted by mattfranklin

Just discovered that the water pump weep hole is leaking. Then discovered that this truck has the *long* water pump. The PO did say the motor came from a '78 truck, so they must have taken all of the accessories from the '78, too. I think for now I'll stick with that setup and just buy a long pump to get it running and driving.

I found this thread with some good discussion:
http://67-72chevytrucks.com/vboard/s...d.php?t=436448

Are you having issues with anything lining up? If not, why not just leave it with a long pump?

[mattfranklin]

Originally Posted by DD1

Are you having issues with anything lining up? If not, why not just leave it with a long pump?

Definitely going with the long pump for now. Got a Gates pump on Amazon Prime for only $25 delivered (and I broke my new "no paint" rule by painting it) . Not yet sure about alignment issues -- the PO didn't use the long pivot bolt but had some funky c-bracket rigged up. It worked ok but wasn't any kind of stock as far as I could tell.

Ordered the long alternator pivot bolt plus spacer and some PCV parts and vent pipe, air cleaner, flame arrestor, and so on from the Corvette LT-1 and Camaro Z-28/LT-1 parts houses. Next couple of weeks I should get those in.

I know I owe you guys a lot of pics. The motor is looking pretty sweet.

[mattfranklin]

It runs! I finally got it going this past Saturday. Such a relief. Calling it a post-Christmas miracle. It's great at mid- and high-rpm. Does not idle. Starts only with starter fluid. I revved it for about 20 minutes to make sure the cam was broken in. It sounds really, really good when it's revving.

I didn't have a timing light and so guessed at position. I hadn't needed one for about 10 years for the kinds of cars I was working on and my old one was broken. Now I need one. I have a new (used Craftsman eBay) one on the way, arriving Monday. But a buddy offered to lend his this week. I have Friday off, so I'll try to dial it in then.

In the past I've done a pretty good job without a timing light, but I need to get it idling first. Adjust it for best idle and make sure it doesn't knock at WOT uphill. Then advance it a little until it just barely knocks at WOT uphill on RUL. And then play with it a little back and forth until it drives nice. But of course once I have the light I'll know what the best settings are.

[mattfranklin]

Next issue, even though it ran strong for 20 minutes plus at mid rpm during the cam break in it doesn't have enough oomph to refill the carb bowl after the prime burns up. I tried several times and my guess now is that it's the sock filter in the tank. I ordered a new sending unit from Eckler's. We'll see what happens.

[mattfranklin]

Replaced the fuel tank sender (even though the old one looked new) and blew out the line with compressed air. Also, inspected carb bowl and float (looked clean and float moved freely) and replaced sintered brass inlet filters. It started on starter spray, but then kept running strongly a long time. I was able to confirm the initial timing (with vac disconnected) at ~12-14 deg +/- and adjust the idle mixture screws to best idle plus a quarter turn out (all 4 of them).

Now it still seems to be overheating. (Previously, during the break-in, it did not overheat during the high rpm, only when I tried to lower the speed toward idle.) Will replace cap and thermostat. If that doesn't do it I'll get a shroud for the fan. Does anyone know the quality differences between Classic Industries and LMC? I think the LMC one is about $60 and the other one is about twice that. Maybe I have that backwards.

Got a new proper GM dipstick with new upper and lower tubes to replace the old one with the bent upper tube. I realized why the old one was bent -- so it would fit with the shorty headers. Oh well. Now looking into stock/Corvette ram's horn options for exhaust manifolds so the proper dipstick will work. Looking at DD1's (Darien's) build and this link, too, for ram's horn manifold options: http://67-72chevytrucks.com/vboard/s...d.php?t=653906

[mattfranklin]

Sorting out the shifter knob. My truck came with an aftermarket aluminum knob kind of half jammed on. The shifter thread was a little dinged up so I chamfered it. It measured 0.374 and looked like a fine thread so I bought a 3/8-24 nut to test it. Could not tease it on. So I bought a 10M-1.00pitch nut and it fit perfectly. Now to find a knob.

EDIT1: It looks like M10x1.00 might not be a thing, despite the box labeling for the nut. So maybe it's a 1.25mm pitch?

EDIT2: There is an M10x1.00 nut available, but have not yet seen a shifter knob with one available.

[DD1]

Looks like you are making great progress. Wish I could say the same.

Keep it up!

[mattfranklin]

Originally Posted by DD1

Looks like you are making great progress. Wish I could say the same.

Keep it up!

Thanks. I know it's hard with the weather.

Upon good advice I got here on the drivetrain forum I wound up running a 3/8-24 die down the shifter threads. I little resistance at the top, but then it got easier the rest of the way down. Once that worked, I ordered a proper round knob.

I also dug into the overheating issue. Not positive, but I think I might have originally put the thermostat and gasket together in the wrong order. Now I understand it should be thermostat first into the manifold, pointy side up and springy side down, then the hard plastic gasket with the printed on silicone sealing surfaces, and then the gooseneck. Not a hint of overheating at any speed.

Also got the seat back in.

May be ready for a test ride soon.

[mattfranklin]

Last weekend ran a 3/8-24 die down the shifter knob treads. Now the new ball screws on great.

[mattfranklin]

Next up, will be installing a fan shroud. Ordered one from LMC, about $80 taxed and shipped.

May add a thermostatic fan clutch like these guys recommend:
http://67-72chevytrucks.com/vboard/s...d.php?t=629097

And this is a good reference, too.
http://67-72chevytrucks.com/vboard/s...d.php?t=520163



AND, just might put it back on insurance this week and take it off of non-op registration.
Maybe a test drive soon.
Scary.

[mattfranklin]

New LMC fan shroud in. And now right-side-up even -- warning stickers came stuck to bottom which confused me for a few minutes.

Now just have to get the grille and hood latch back together and then get insurance and registration back on it. Oh, and tires. ;-)

Hope to be test driving soon.

[DD1]

Hey Matt, Post some pics for us!

[mattfranklin]

Originally Posted by DD1

Hey Matt, Post some pics for us!

You're right! Maybe this weekend.

[mattfranklin]

I'm so lame on pictures. Anyway, here's what I was doing recently...

I was having trouble making it idle at a reasonable rpm. Every time I tried to dial down the rpm I'd get a stumble, stumble, stumble and then it would die. I was assuming that my almost new (in actual running hours) carb was damaged from backfiring or years of old gas sitting in it and occasionally running through it.

Yesterday while I was fiddling, and the engine was warm but had just died, I noticed a plume of vapor rising from the back of the carb. And it kept going. I was worried I had a little fire and that the plume was smoke. When I was able to crane my neck and see, I saw that there was a 3/8" uncapped port under the rear fuel bowl. Doh! Massive vacuum leak. No wonder it wouldn't idle! I could not believe it! #1 that I was so absent minded to have missed it for so long, and #2 that I was so lucky to have finally found it today.

Bottom line, I capped it and readjusted the idle mixture screws (about 1-3/4 to 2 turns on the primaries and 1 the secondaries idle was about right to make it smooth) and reset the idle speed and now it runs great. Now I just need to install shocks, hood latch, add insurance, and register it as operational and go for a real road test.

[DD1]

Originally Posted by mattfranklin

I'm so lame on pictures. Anyway, here's what I was doing recently...

I was having trouble making it idle at a reasonable rpm. Every time I tried to dial down the rpm I'd get a stumble, stumble, stumble and then it would die. I was assuming that my almost new (in actual running hours) carb was damaged from backfiring or years of old gas sitting in it and occasionally running through it.

Yesterday while I was fiddling, and the engine was warm but had just died, I noticed a plume of vapor rising from the back of the carb. And it kept going. I was worried I had a little fire and that the plume was smoke. When I was able to crane my neck and see, I saw that there was a 3/8" uncapped port under the rear fuel bowl. Doh! Massive vacuum leak. No wonder it wouldn't idle! I could not believe it! #1 that I was so absent minded to have missed it for so long, and #2 that I was so lucky to have finally found it today.

Bottom line, I capped it and readjusted the idle mixture screws (about 1-3/4 to 2 turns on the primaries and 1 the secondaries idle was about right to make it smooth) and reset the idle speed and now it runs great. Now I just need to install shocks, hood latch, add insurance, and register it as operational and go for a real road test.

Sometimes the small things get overlooked. Glad it was an easy fix.