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Help me plan the 78's future cam choice.

y5mgisi

y5mgisi

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Im pretty sure this summer im going to freshen up the 350 in my 78 k25. Its going to be pretty much just a stock bottom end rebuilt as stock. Stock oil pump etc. If it needs bored or the crank ground then whatever. Im going to run the stock heads. Agian, whatever they need as far as a stock style rebuild.

Its going to keep the edelbrock performer intake but im going to switch to late model exhaust manifolds (the tbi/vortec ones supposedly flow better). So its going to be a mostly stock motor.

I know my needs/wants for the truck and thats to have the motor dialed in to a woods truck/DD/cruiser/tractor type truck. So my real tough choice comes to the valve train.

I was thinking about just using a stock cam(1). Then i was thinking about using a stock cam with 1.6:1 rockers. Then i was thinking about using the summit 1101(2) cam or that cam with 1.6:1 rockers. And then i was thinking about using the summit 1102(3) cam. And then i was thinking about using that cam with 1.6:1 rockers and/or advancing the cam a few degrees.

Im looking for in site on what you guys think i would be happiest with to meet the goals of this truck. I want smooth idle, good throttle response, good vacuum, etc. but i dont want to sacrifice any power i would get from a bigger cam, as long as that bigger cam doesnt hurt any of the aforementioned goals. I DONT want a choppy idle or any of that business. I want it to have as much power as possible while still running like stock. Its not a mudder, its a woods truck. So what of the following choices do you think would suit my needs best?

1, Stock cam.
1a, Stock cam with 1.6:1 rockers.
2, Sum1101 cam
2a, Sum1101 cam with 1.6:1 rockers.
3, Sum1102 cam
3a, Sum1102 cam with 1.6:1 rockers.
3b, Sum1102 cam with 4* advance (optional 1.6:1 rockers)
4, Your sugsetion

Here are the cam specs

Stock,
195/202, 112/108, .390"/.410"

Sum1101,
Intake Duration at 050 inch Lift: 194
Exhaust Duration at 050 inch Lift: 204
Duration at 050 inch Lift: 194 int./204 exh.
Advertised Intake Duration: 252
Advertised Exhaust Duration: 262
Advertised Duration: 252 int./262 exh.
Intake Valve Lift with Factory Rocker Arm Ratio: 0.398 in.
Exhaust Valve Lift with Factory Rocker Arm Ratio: 0.420 in.
Valve Lift with Factory Rocker Arm Ratio: 0.398 int./0.420 exh.
Lobe Separation (degrees): 112

Sum1102,
Basic Operating RPM Range: 1,500-4,000
Intake Duration at 050 inch Lift: 204
Exhaust Duration at 050 inch Lift: 214
Duration at 050 inch Lift: 204 int./214 exh.
Advertised Intake Duration: 262
Advertised Exhaust Duration: 272
Advertised Duration: 262 int./272 exh.
Intake Valve Lift with Factory Rocker Arm Ratio: 0.420 in.
Exhaust Valve Lift with Factory Rocker Arm Ratio: 0.442 in.
Valve Lift with Factory Rocker Arm Ratio: 0.420 int./0.442 exh.
Lobe Separation (degrees): 112

:bow:
 
My blazer has the 1103 in it with 1.6 roller rockers. I like it. I'd like more for my purposes though. But it runs fine around town and plenty of vacuum.
 
Just after motor install. Note, my mufflers have zero baffling, just straigh through so that's a lot of the loud...

DSCF9819.mp4
 
See Adam yours runs good, this one however, is what i DONT want,

[YOUTUBE]_K-XV3Yum8k[/YOUTUBE]
 
I have the 1102 in the 350 that I pulled from the k5. Smooth idle, good vacuum. It's about the same cam as the 260hp crate 350 from gm.

The secondarys come open at 4000 on the q-jet. It pulls hard from there to 5000. I have shifted it at 5600 ish and it still was making some good power. Obviously you aren't too concerned about that. But it was a perfect cam for a dd. I just hammer on my sh!t when needed.

Get some cast pistons that get your compression into the high 8s. That with a .030 over bore and some distributer miss will give you a descent boost in power.
 
Far as exhaust goes, i plan on running the manifolds, with dual 2.5" into "turbo" mufflers all the way out behinde the tires with an h-pipe. I think that would be fun. I also have been thinking about mimiking a stock 454 late model exhaust. Its a dual 2.5" into a y pipe and 3" from there back. I would run a 12"x3" glass pack as a resonator where the cat would go, and then do a stock muffler from about a 95 454 truck. I have always liked the way those things sound. Throaty without being loud. Should flow a plenty for what i want also. Decisions decisions!
 
y5mgisi said:
Far as exhaust goes, i plan on running the manifolds, with dual 2.5" into "turbo" mufflers all the way out behinde the tires with an h-pipe. I think that would be fun.
Click to expand...

Yah that should be ok, turbos are a lil quiet for me but still sound good.
 
Mods makes much more sense!!! And yes i plan on doing a bit with that! I do need a little more mpg out of this thing! Its about 7mpg right now which is stupid. I dont expect great numbers but there is no reason this truck shouldnt get 11 in town and 13 highway with the way i drive.
 
With this build, another few things that im going to do is ditch the chrome valve covers for stockers, shave the edelbrock off the intake and paint the whole engine the proper chevy orange!
 
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