Topic: 75 engine buildup
in Forum: C3 Engines
Already a Member?
Click Here to Login
Not yet a Member?
Click Here to Register for Free!
I have 75 L48 with a 350,I beleive that it not the origional motor.I want to make it run better,and lookbetter.My plans are to put headers on it with the pipes running out the back of the car(it has hooker side pipes on it now).Also I want to put the edlebrock two four intake on it.This will give me a intake with two 500 CFM carbs on it. I want a car that has a nice looking engine that runs smoothe. I'm not looking for a street terror.What I need to know is type of mods I need to do.
SPONSOR AD:: (Our Sponsors help support C3VR)

Moderator
Moses Lake, WA - USA
Joined: 4/16/2005
Posts: 2134
Vette(s): 1976 L48 4-spd, Mahogany Metalic exterior, Buckskin interior 350ci/350hp, 3rd owner, fiberglass spring, 255/50-16's Torq-Thrust II
What you need to do first is try and determine the overall condition of your motor. How many miles are on it or maybe do a compression test and leak down test. This will tell you if it is getting close to a rebuild time. A well worn motor won't perform well no matter what you put on it. Dual Quads is way to much carburation for a street-able 350. May look cool but not ideal for the street. If your motor has its original heads those will need to be replaced or reworked for better flow. Your vette like mine just don't breath well. An inexpensive way to go with heads is the GM Vortech heads. You will also need a more aggressive cam than what came in the stock motor. Add a good manifold then your in business. Putting together a good street-able motor takes a little research. All the parts need to be matched from a performance stand point so they all can enhance one another. Pick up some books on building Chevy small blocks and read up on what your trying to do. They provide lots of good info. Or you can go the route of a GMPP crate motor. These motors take all the guess work out figuring what works and what doesnt. Could could also seek out a good engine builder, but may run a little more that a crate motor. The old saying is HP=$$.
Welcome to the forum

One other thing you have to remember,watch your hood clearance,most of those dual quad manifolds are high rise,you need a low profile manifold to keep from punching a hole in the hood 

C3VR Lifetime Member #93

SHELBYVILLE, TN - USA
Joined: 7/5/2002
Posts: 3942
Vette(s): 1976 L48 auto
1978 L82 4speed
1994 LT1 6speed
1978 L82 4speed
1994 LT1 6speed
That is true about the dual quad set up, for hood clearance... tried a vintage dual 4bbl on the 76, with the stock hood..it wouldn't close. There are smaller 4bbl carbs out there too... i've been toying with the idea of 2 450 cfm to go onto the 78 vette... it has a high rise hood, sooo i hope clearence isnt a problem... though, gas milage might be....
I know that I will have to a rebuild on my motor,however i frist must figure out what I really have for a motor.I don't think it is the factory motor.A friend is getting me the info so can check the numbers.The intake that I like will fit under the stock hood,because I saw the setup on a 76 vette.Thanks for the welcome,bing new to the hobby I have alot to learn.
in Forum: C3 Engines
SPONSOR AD: (Our Sponsors help support C3VR)