Waking up my 350 SBC

[ChevyDude]

My Red 71' called Lil' Red was a big score when I found her 5 or 6 years ago. She was in primer and I was told that the 350 SBC had just been rebuilt. Well, I have had her on the road for about 3 months now and I am just not happy with the HP. The engine doesn't smoke and has very good compression. So.....my Plans: Engine will be pulled from Lil' Red this Saturday. New aggressive Crane 488-515 lift cam, new lifters, new hi Rise square bore aluminum Intake, new double roller timing chain, new mechanical 750 DP Holley or Barry Grant, new aluminum 64cc 202/160 heads.

Should wake up Lil' Red.

[LONGHAIR]

new mechanical 750 DP Holley or Barry Grant

For street driving, you would be ahead to use a vacuum secondary carburetor. Double pumpers are a full accelleration (drag racing only) thing.

[straitnate14]

Originally Posted by LONGHAIR

For street driving, you would be ahead to use a vacuum secondary carburetor. Double pumpers are a full accelleration (drag racing only) thing.

??? I dont have any problems on the street with my 700 dp? It gets terible gas milage but thats pretty much to be excepted.

[lowriden58]

Originally Posted by straitnate14

??? I dont have any problems on the street with my 700 dp? It gets terible gas milage but thats pretty much to be excepted.

same here with my 750DP i drive it on the street with no problems at all even witha 3k stall. only problem i have is "she will pass everything but a gas station"

[67_C-30]

For a daily driver I would not go with a DP, but there again I would not go with Holley at all. However, If you looking for HP, I'd go with the DP. In my experience, the double pumper can make for significantly more low speed torque, at the expense of fuel economy. As long as you don't actuate the secondaries, it uses no more fuel than a vacuum carb with the same size primary throttle bores, booster type, jetting and idle mixture. On a vacuum secondary carb, the vacuum is only actuated after a certain point of throttle opening. Then the airflow through the primary venturi (not engine vac) actuates the vac diaphragm which opens the secondaries. Because this is slow and linear, it is not neccessary to have the second accelerator pump which hides the "hole" created by the near instantaneous opening of the secondaries when you "punch it". The bog from most carbs when flooring it is by too little gas being applied from the accelerator pump and not by too much gas as most people believe. I have never had a DP bog on any engine, even if it was too big for the engine. The vacuum secondary carbs can be troublesome to keep adjusted as well in regards to the vacuum diaphram. If I were buying a carb for power (which what you seem to be doing) I would personally would not waste my money on a vacuum carb even though the so-called experts say you should use them on the street. JHMO

[ChevyDude]

I hate the 600 Edelbrock E choke carb I have now and the amount of driving I do.....she is gonna run like a hot rod. A friend just built his 64' Chevelle engine as I discribed above and it runs awesome. That's what I am looking for.....and heck...I only live 15 miles from Bandimere Speedway, LOL.

[cdowns]

you might want to ID what heads you have before changing to an aggressive cam poor heads are poor heads doesnt matter how far you open the valves or how long they stay open/ rhen theres the question do you have pressin or screwin rocker studs not to mention the valve spring height how about piston clearance?

all in all your plan is a poorly thought out one

[LONGHAIR]

all in all your plan is a poorly thought out one

That's a little harsh....but the point of the rest of the post is at least somewhat accurate. There needs to be a plan, with matched parts.

Does anyone really make a "bad" aluminum head for a SBC though?
I'm still focusing on the carburetor. I'm not a big Edelbrock fan either, but a double pumper is not going to be optimum for the street. Just because someone else "did it" and it worked for them, doesn't mean that they were getting the most from it either.

[ChevLoRay]

Far be it from me to try and second-guess anyone on their plans.

You mentioned that you were unhappy with your Edelbrock 600cfm (model 1405?) with electric choke. I have the same one, but w/o the electric choke. In the configuration I have, it's classified by Edelbrock as a "performance" carb, with the main jets being .100's. It ran rich and would gas-foul the plugs in a couple or three months.

I changed intakes to a Perfomer and the carb to an Edelbrock 1901 Q-Jet, with electric choke. It's rated at 750CFM and I couldn't be happier. Check out www.edelbrock.com for tuning tips for all their carbs, as well as technical info.

As an aside, and not to hijack the thread, but has anyone ever used a Thumpr cam in an engine? I'm considering the L79 version (350HP/327) for my '69. It's an automatic and the literature shows it to be workable. Just curious. Good luck on your engine work.

[ChevyDude]

Originally Posted by cdowns

all in all your plan is a poorly thought out one

Hey Dude you have absolutely no idea what you are taking about, period. This package is has been matched and put together by Smith Racing of Denver, whom has done numerous winning engines. Seems a bit out of line for you to tell me my plan has been poorly thought out after many hours of disussing what we should do with the owner Tom Smith, when you know NOTHING of what has been dicussed.... but whatever Cdowns. and cdowns...heads were ID'd long before you spoke up and they are lousy heads for making power...that's why I said new aluminum heads were being purchased. Your negitive comment is out of line, and adds nothing positive to this board!

I did not post what I was doing to get a cheap shot from someone, seems kinda F'd up....don't ya think??? I will probably delete this whole post if it goes on a negitive pissing match route, as I cannot stand some idiot spouting off like this when he knows nothing of what has been discussed...it pisses me off and truly I do not come to this board to share info only to get slammed by someone like cdowns.

Trans is a 500 hp rated 700R4 built by Monster Motor Sports...It has a 2500 Stall convertor, because when I bought the truck the PO told me the engine had been rebuilt and was near 400 hp....he lied!!!! So to leave it as it is, nothing is matched up as I had the trans built thinking the engine was 400 hp.

This truck is not a daily driver, nowhere near. This truck is a HOT ROD, and when I want the secondaries open ...I step on the pedal...and do not have to wait for vaccuum.

[straitnate14]

Originally Posted by ChevyDude

This truck is a HOT ROD, and when I want the secondaries open ...I step on the pedal...and do not have to wait for vaccuum.

[milled]

Ok, if it wher me I wouldn't exceed .500 lift on the cam. I perfer a carter 4bbl jetted and metered, it'll feed anything. Other than that small blocks rule

[70rs/ss]

Originally Posted by ChevyDude

Hey Dude you have absolutely no idea what you are taking about, period. This package is has been matched and put together by Smith Racing of Denver, whom has done numerous winning engines. Seems a bit out of line for you to tell me my plan has been poorly thought out after many hours of disussing what we should do with the owner Tom Smith, when you know NOTHING of what has been dicussed.... but whatever Cdowns. and cdowns...heads were ID'd long before you spoke up and they are lousy heads for making power...that's why I said new aluminum heads were being purchased. Your negitive comment is out of line, and adds nothing positive to this board!

I did not post what I was doing to get a cheap shot from someone, seems kinda F'd up....don't ya think??? I will probably delete this whole post if it goes on a negitive pissing match route, as I cannot stand some idiot spouting off like this when he knows nothing of what has been discussed...it pisses me off and truly I do not come to this board to share info only to get slammed by someone like cdowns.

Trans is a 500 hp rated 700R4 built by Monster Motor Sports...It has a 2500 Stall convertor, because when I bought the truck the PO told me the engine had been rebuilt and was near 400 hp....he lied!!!! So to leave it as it is, nothing is matched up as I had the trans built thinking the engine was 400 hp.

This truck is not a daily driver, nowhere near. This truck is a HOT ROD, and when I want the secondaries open ...I step on the pedal...and do not have to wait for vaccuum.

I am going to say a couple of things, and I hope my post isn't too far down for it to have been said a couple of times before, but when I first read your OP I thought exactly what cdowns thought, then I reread your post and then I saw the bit of info I missed, which was the alum 64cc 2.02/1.60 heads. I think he was going off the fact that you were adding a ton of serious parts to an unknown headed SBC. I do not think he off on his comments about the plan given (I am assuming here as I was thinking along the lines of his post when I first read your OP) he thought you were using an unknown iron head, but his manner of commenting was a bit harsh (I am not defending that at all).

Now on to my thoughts, that top end set up sounds like it will be knarly, but you are adding a lot of high dollar parts to an unknown short block, which means it could be bone stock with OE stuff (cast pistons {maybe even dished}, reused rod bolts and cheapy cast rings) that being said, it could grenade the bottom end in short order. If it was just stock rebuild it probably wasn't balanced so anything over 5k rpm (which that cam, heads, intake are going to want to do and up to 6500 rpm) you will be pulling the pin on the grenade and waiting for the boom. A good perf oriented short block can be had for $800 and up and would be a good investment if you want it to hold up to the rest of the parts. Heck you can get a built 383 short block with a warranty for $1000-1500 from GM and many other sources).

I am trying to err on the side of caution since I hate to redo anything on my junk. Ultimately this is your ride and you'll do as you want (and so would I), but you asked so we answered. I know your motor will run good and perform better than it does now, as it probably has low compression and tiny cam, iron intake etc. It is just wether you want to risk blowing up the stock bottom end and hurting a head or the cam, etc, etc. If a rod bolt fails you could wreck one or both heads. My gut says to tell ya to sell your motor for whatever you can get for it ($3-500 towards a short block can't hurt, right?) and invest in building a short block or have one built, and a 383 will do more than the 350, see how adding a little more umpff can get out of hand!?

[Gray Ghost]

Originally Posted by ChevyDude

Hey Dude you have absolutely no idea what you are taking about, period. This package is has been matched and put together by Smith Racing of Denver, whom has done numerous winning engines. Seems a bit out of line for you to tell me my plan has been poorly thought out after many hours of disussing what we should do with the owner Tom Smith, when you know NOTHING of what has been dicussed.... but whatever Cdowns. and cdowns...heads were ID'd long before you spoke up and they are lousy heads for making power...that's why I said new aluminum heads were being purchased. Your negitive comment is out of line, and adds nothing positive to this board!

I did not post what I was doing to get a cheap shot from someone, seems kinda F'd up....don't ya think??? I will probably delete this whole post if it goes on a negitive pissing match route, as I cannot stand some idiot spouting off like this when he knows nothing of what has been discussed...it pisses me off and truly I do not come to this board to share info only to get slammed by someone like cdowns.

Trans is a 500 hp rated 700R4 built by Monster Motor Sports...It has a 2500 Stall convertor, because when I bought the truck the PO told me the engine had been rebuilt and was near 400 hp....he lied!!!! So to leave it as it is, nothing is matched up as I had the trans built thinking the engine was 400 hp.

This truck is not a daily driver, nowhere near. This truck is a HOT ROD, and when I want the secondaries open ...I step on the pedal...and do not have to wait for vaccuum.

Amen....I've seen tons of trucks running very similar combos and working well I might add. Plenty of folks run DPs on the street as well.

[LONGHAIR]

Plenty of folks run DPs on the street as well.

Plenty of folks will defend the use of "welded spiders" or "spools" on the street too........It still doesn't make it right.

There are plenty of "old school way of thinking" things that guys are willing to "deal-with" or "tune-around", but there are also plenty of new guys out there reading the stuff on this board, who don't need the confusion.
A whole lot of "old school" things were done because that was all there was available, or the technology hadn't been developed yet.
I have no issue at all with old school looks/style, but I am not willing to ignore the better stuff that has come along since.

Performance, safety, and fuel economy are all better today because of improvements to the old way. I'm not saying that everything that is new is better...some of the oldler/simpler ways have advantages too.....But "racing stuff" is just that, it does not automatically translate to street driving. Sure some do it....but it doesn't make it right.

Non vacuum-advance distributors
Tiny racing convertors
Non DOT tires
Dominators
Trans brakes
Tunnel rams
Spools
Nitrous Oxide
Blah
Blah
Blah.....

(staff comment)
Keep it civil, there was plenty of negativity (personal) in this thread, there is no need for that at all. Dis-agree....fine, no name calling or personal slamming...and please quit "quoting" the old bad stuff and bringing it back up.
I re-opend this thread because I believe that there is good information available, please don't make that into a mistake...

[67dragtruck]

Originally Posted by cdowns

you might want to ID what heads you have before changing to an aggressive cam poor heads are poor heads doesnt matter how far you open the valves or how long they stay open/ rhen theres the question do you have pressin or screwin rocker studs not to mention the valve spring height how about piston clearance?

all in all your plan is a poorly thought out one

Maybe you should pay attention before spouting off. He already said he was putting new aluminum heads on it. Sounds like a good combo to me.

Tom

[Bob 68327]

Originally Posted by 67dragtruck

Maybe you should pay attention before spouting off. He already said he was putting new aluminum heads on it. Sounds like a good combo to me.

Tom

[ChevyDude]

Originally Posted by 67dragtruck

Maybe you should pay attention before spouting off. He already said he was putting new aluminum heads on it. Sounds like a good combo to me.

Tom

Ahhhhhh.....my feelings exactly!!!!

Perhaps he was looking over his social security benefit check and missed that line where I stated Aluminum Heads were being purchased????

This is only an attempt at comedy ...nothing personal. Maybe I'm better at comedy than engine building??? LOL!

[haysonj]

Originally Posted by 67dragtruck

Maybe you should pay attention before spouting off. He already said he was putting new aluminum heads on it. Sounds like a good combo to me.

Tom

Is that with or without the dish pistons

[bigfredtn]

I went mechanical and I will not be going back to vacuum carbs. My truck is a weekend cruiser so the gas mileage issue was a non issue. I also went to mechanical dist also. Have fun with your new hot rod. THe only thing I would have done differently, I should have installed a Hyd. Roller.

[whatnow123]

This is close to what I'm running depending on the type of heads you have, but all I can say is it should wake it right up... my truck hauls ass once it hooks up at 40mph or so....

[steelhorse]

I would go with the edelbrock performer rpm air gap for intake.Every buildup I have seen with it they are very hard to beat.I too would go with a 750 vac secondary holley.Check out websites like car craft/popular hot rodding for engine builds you should see some good info in them.Remember to check the rpm range for the hp/torque if this is going to be mainly for the street.

[johnnywagon]

The Edelbrock RPM Air-Gap is a great intake. It even helps with slightly lower engine coolant temps. I had one on my 10 second pro-street 406 Chevy Luv w/a Demon 750 DP. Got one on my 65 Chevelle w/Edelbrock 600 carb and my Blazer has one w/a Q-Jet and carb adaptor.

[70c10]

Alex, do you have an auto trans?. That cam is going to want some stall and gears especially in a truck! If your dead set on a DP I'd go for a 650. When I switched from the Edelbrock to the Demon it was a huge improvement! I will be running the RPM Air Gap soon with with my new Brodix IK180 heads!

[ChevyDude]

Cam spec: 488-510 LIFT, 234-244 DURATION, 114 LOBE SEP.