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Need suggestions on building up a 350 Chevy

10K views 15 replies 8 participants last post by  JAKE 68 GMC 
#1 ·
I may be getting a newly rebuilt 1982 Chevy 350 sometime soon. The seller said they rebuilt it completely stock with no performance parts, the only thing non-stock was a double roller timing chain. It's even got a stock GM intake on it. My goal was to soup up this motor enough to make the truck fun to drive. I don't really want it lightning fast (that ain't what trucks are for ;) ), I just want some good, somewhat quick acceleration, low-end torque, and enough go-nads to pass a car when I have to.

I was wondering was some of you guys would reccomend as far as camshafts, intakes and carburetors go for a 350. I'm going to run the stock ramhorn manifolds because headers rust out too quickly up here. The motor will be going in to a 1968 GMC 3/4 ton 4x4, with a 4-speed, 4.10 gears, and 33 inch tires. The truck has the rare, torque monster 305 GMC V6 in it now, but she's starting to show her age, and I'd like to have something with a little more snap to it.
Any and all help will be appreciated. This is my 1st truck, and I want to have as much fun as possible with it while I can.
Jake
 
#2 ·
Get ceramic coated headers, the stock manifolds will negate most of the other improvements you make. In fact headers are the first thing I'd do. There are some great deals on eBay on ceramic coated Chevy truck headers. I just bought a pair for my '89 C1500 and they are really nice.

A Lunati VooDoo 262 or similar cam, Edelbrock Performer RPM manifold, recurved HEI and Edelbrock Performer 600 Carb will round it out nicely. I usually prefer Q-Jets but the Performer is a decent carb and much simpler to work on. IT won't be a high RPM screamer but should have a lot more passing power and you'll see a big boost in the bottom end when you're off the pavement or pulling a load.

If you go on eBay looking for parts and you see anything from a seller called "stanwhite" you can buy from them with confidence, see my post in the Lounge.
 
#3 ·
No point opening up the intake if you can't let it out. If you can't afford ceramic coated headers then at least try to find some high perf 3 inch outlet Corvette rams horns. Only then can you see any gains from intake mods.
Stay mild, cam under 220 @ 50 and no more than 480 lift. Fit new rockers if the old ones were reused as they wear with a 'step' and will eventually break with more lift.
Some people hate q-jets, I love 'em. Never met a carb with better response/drivability/economy trade off. Try carb spacers, if it goes harder with an open spacer it needs more plenum, worse - use a smaller carb. Trial and error as every vehicle has different needs.
 
#4 ·
IanRiordan said:
No point opening up the intake if you can't let it out. If you can't afford ceramic coated headers then at least try to find some high perf 3 inch outlet Corvette rams horns. Only then can you see any gains from intake mods.
Stay mild, cam under 220 @ 50 and no more than 480 lift. Fit new rockers if the old ones were reused as they wear with a 'step' and will eventually break with more lift.
Some people hate q-jets, I love 'em. Never met a carb with better response/drivability/economy trade off. Try carb spacers, if it goes harder with an open spacer it needs more plenum, worse - use a smaller carb. Trial and error as every vehicle has different needs.
The "Vette" manifolds were 2-1/2" and a good used set will cost almost as much as a decent set of headers here in the US unless you stumble across somebody that doesn't know what he has. They were also used on '62-'64 full size Chevies with the 327/300HP, on average they go for about $150 a pair, I have just under $170 in my headers including freight. They're welded "off shore" though so if that's an issue you better stick with manifolds or be prepared to pay through the nose for name brands. For the record mine have a better fit and finish than any headers I have ever owned and the ceramic coating was done n the US, a lot of the big names have had their's welded in Mexico since the 70's. I compared mine to the Summit house brand headers they sell for my truck and they were 100% identical but the Summit's were $120 more. I'd be willing to bet that $120 the Summit's came from the same place.

Stainless steel truck headers are also going for about $149.00 plus freight on ebay, again these will be "off shore" stuff. They transfer a bit more heat to the engine compartment than ceramic coated but they won't rust out. Ceramic coated block huggers are a little cheaper and would work since your truck originally came with ram's horns if price is an issue.
 
#5 ·
Thanks for the help. I thought the stock ram-horns flowed pretty good for stock cast-iron manifolds? Another problem with headers is that for 67-72 GM 4x4's, you need to modify the clutch linkage if your running a manual tranny. That was another reason i was going to keep the stock manifolds.
 
#6 ·
For what your trying to do, the stock rams horns will work fine. I`d use a edelbrock performer plus camshaft kit, along with the performer intake, I`d use a Quadrajet carb. If it still has a points ignition ditch it and get a HEI, don`t waste your time on points. Use spiral core spark plug wires and tune it up with the best pieces you can afford. Also use a K&N airfilter.
This combo will give you outstanding off idle torque, it`ll also help mileage.
The cam has more duration on the exhaust side by 10 degrees, chevy exhaust ports are very efficient in stock form so the rams horns will work fine. Use a dual exhaust with a X or crossover pipe with some turbo mufflers.
one last note, when you go to do the cam break in, fill the engine with diesel oil, after the break in, change the oil and filter back to standard oil. The gov had the oil companies remove alot of additives in the oil, so standard oil doesn`t lube the cam well enough to keep from wiping it out on break in, also make sure you use the valve springs that match the cam.
 
#7 · (Edited)
Hippie said:
Get ceramic coated headers, the stock manifolds will negate most of the other improvements you make. In fact headers are the first thing I'd do. There are some great deals on eBay on ceramic coated Chevy truck headers. I just bought a pair for my '89 C1500 and they are really nice.

A Lunati VooDoo 262 or similar cam, Edelbrock Performer RPM manifold, recurved HEI and Edelbrock Performer 600 Carb will round it out nicely. I usually prefer Q-Jets but the Performer is a decent carb and much simpler to work on. IT won't be a high RPM screamer but should have a lot more passing power and you'll see a big boost in the bottom end when you're off the pavement or pulling a load.

If you go on eBay looking for parts and you see anything from a seller called "stanwhite" you can buy from them with confidence, see my post in the Lounge.
I agree, but think the Performer RPM is overkill. I like the Comp CS XE256H-10 or CS XE262H-10 coupled with the Performer EPS. I always run new engines with a bottle of GM EOS - Engine Assembly Prelube.
 
#9 ·
71C10 said:
I agree, but think the Performer RPM is overkill.
I used to too but I have seen it used with great success on mild small blocks and it has a little better resale if he should want to sell it.


JAKE 68 GMC said:
I thought the stock ram-horns flowed pretty good for stock cast-iron manifolds? Another problem with headers is that for 67-72 GM 4x4's, you need to modify the clutch linkage if your running a manual tranny. That was another reason i was going to keep the stock manifolds.
The key there is "for stock cast iron manifolds..........." Have you looked into shorties or block huggers? The block huggers are center dump like the ram's horns and don't go anywhere near the clutch linkage. The ram's horns will work but you'd see more improvement with headers. With the headers, gaskets and hardware available now they aren't the hassle they used to be. BUT it's your truck and you're the one that has to live with it.
 
#15 ·
Hippie I think you meant skip white.I buy alot of stuff from him on ebay,cant touch his deals on hei's.
I had a 256H xe comp cam in my 72 C10 for awhile It had great power on the low end,I just swapped it out because I wanted a lumpier idle.I had enough power to smoke the local mustangs/camaro's.I still got 18mpg in it too.
One thing is your truck is'nt going to have is a good top speed.I started out with a TH400 and 4.10 rear gears with a 31"tire,and 70mph freeway speed for me was 3600rpm.Not much past that,I ended up swapping to 3.73 gears and a th700r4 trans O/D.Dropped the rpm down to 2400-2600rpm.For you I might swap to a 5 spd with o/d,if you plan to any freeway driving.
I would do this:
350ci
256H xe cam
1.52 Roller tip rockers
Performer intake
600cfm Edelbrock Performer carb
Hei distributor 50k volts
and a 5spd trans like a tremec would be nice and strong
 
#16 ·
bonzipenguins said:
Hippie I think you meant skip white.I buy alot of stuff from him on ebay,cant touch his deals on hei's.
I had a 256H xe comp cam in my 72 C10 for awhile It had great power on the low end,I just swapped it out because I wanted a lumpier idle.I had enough power to smoke the local mustangs/camaro's.I still got 18mpg in it too.
One thing is your truck is'nt going to have is a good top speed.I started out with a TH400 and 4.10 rear gears with a 31"tire,and 70mph freeway speed for me was 3600rpm.Not much past that,I ended up swapping to 3.73 gears and a th700r4 trans O/D.Dropped the rpm down to 2400-2600rpm.For you I might swap to a 5 spd with o/d,if you plan to any freeway driving.
I would do this:
350ci
256H xe cam
1.52 Roller tip rockers
Performer intake
600cfm Edelbrock Performer carb
Hei distributor 50k volts
and a 5spd trans like a tremec would be nice and strong
Well, it will be rare that I'll ever go over 70mph, I probably won't do much, if any, highway driving, so I should be set with the drivetrain. This info really helps out, I think if I put in a mild 350, the truck should go pretty good, low-end torque and acceleration wise. Thanks for all the help, I appreciate it.
 
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