engine tuning
Thread Starter
Instructor
Joined: Nov 2006
Posts: 232
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From: fairfax va
engine tuning
hello, this is my first post. i love the site and all the imformation u guys share! 1980 corvette, 350L48 bottom end,xe-268 cam, gm head 58cc 2.02-1.60.edelrpm intake, 600 holley. th350 trans,3.73rear. car runs ok but kind of goes flat in upper rpms.my plugs stay white i have put bigger jets didnt help.holley110gph pumpw-reg@7psi. is the carb to small? any advice would be great. what kind of power should this make? 1\4 mile est.
Drifting
Joined: Apr 2002
Posts: 1,716
Likes: 4
From: New Baden Illinois
Originally Posted by steve dalla
hello, this is my first post. i love the site and all the imformation u guys share! 1980 corvette, 350L48 bottom end,xe-268 cam, gm head 58cc 2.02-1.60.edelrpm intake, 600 holley. th350 trans,3.73rear. car runs ok but kind of goes flat in upper rpms.my plugs stay white i have put bigger jets didnt help.holley110gph pumpw-reg@7psi. is the carb to small? any advice would be great. what kind of power should this make? 1\4 mile est.
Tech Contributor
Joined: Aug 1999
Posts: 14,382
Likes: 6,402
From: At my Bar drinking and wrenching in Lafayette Colorado
Install the short white spring in your secondary diaphragm - the stock spring will not allow your secondaries to fully open. If you have a 4150 carb, run your secondary jetting 8 sizes larges than the primary. Make sure your float levels ar right up to the bottom of the sight hole. Are you running 36 degrees of timing? That's the frist thing to verify.
Burning Brakes
Joined: Jul 2006
Posts: 830
Likes: 1
Originally Posted by steve dalla
hello, this is my first post. i love the site and all the imformation u guys share! any advice would be great. what kind of power should this make? 1\4 mile est.
Steve, welcome aboard!
I too have an 80 350cu in, brand spankin new edelbrock performerEPS intake, 600 cfm edelbrock performer carb, slightly increased cam & shorty headers to a Y pipe, free flow cat & 3" exhaust to the tips.
I just came back from the dyno. While thinking I would pull around 240 to 260 on the dyno because of the improvements listed above, I was quite shocked to pull 182rwHP, 3 consecutive tries...182
So, in order to bump the HP into a bit more of a performance catagory, I am planning on full long tube headers and 62 Edelbrock aluminum heads.
Hopefully these two alterations will finally let the air comming in have a decent place to go, thus increasing those anemic HP numbers.
Please keep in mind that the RWHP dyno takes off about 10-15% HP when you have an Automatic. So, yes HP at the crank would probably run 230-ish. But at the rearwheels with an Automatic, 182RwHP.
Tech Contributor
Joined: Aug 1999
Posts: 14,382
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From: At my Bar drinking and wrenching in Lafayette Colorado
Originally Posted by OregonVette80
RWHP dyno takes off about 10-15% HP when you have an Automatic.
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Burning Brakes
Joined: Jul 2006
Posts: 830
Likes: 1
Originally Posted by steve dalla
have you ever been to dragstrip? what kind of times would yall predict?
AP
Tech Contributor
Joined: Aug 1999
Posts: 14,382
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From: At my Bar drinking and wrenching in Lafayette Colorado
Originally Posted by steve dalla
hey lars , i had timing at 38total. i will change to 36.carb is 600 vac.secondaries thanks for the tip on springs. 600cfm is the right size?
The short white secondary spring will get you an advantage and should help. The 600 cfm carb is smaller than what I usually run on an engine like that - I like the 750 on any performance engine in the 350-400 cubic inches range (and there are people here who will argue that one, but that's what I like to run). Yet, the 600 will give you a nice level of performance (heck, the NASCAR guys run 390's...).
Tech Contributor
Joined: Aug 1999
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From: At my Bar drinking and wrenching in Lafayette Colorado
Originally Posted by BigBlockk
Cubic dollars.
BigBlockk
Later.....
BigBlockk
Later.....
Yup. And you spin the engine at 8,000-9,000 rpm. If you figure the 9,000 rpm number and knowing the horsepower they're putting out, you'll see that the engines are actually down a bit on torque due to the carb limitation. If you let those guys run 1150's, you'd see horsepower numbers simply staggering.