Posted by rickyracer (IP: 209.178.171.250) on October 19, 2000 at 02:12:30:
In Reply to: Exhaust Cross-over posted by Max on October 18, 2000 at 13:18:50:
unless you drive it only on hot days, your engine will run rich. It'll be like driving without a chock when the engine is cold. Only all the time. Airgap manifold is a high rpm, rare street driver, racing manifold. The airgap keeps the air/fuel mixture cooler, therefore a denser and more horsepower generating. Engine heat is insulated from the manifold runners unlike just blocking off the exhaust crossover on standard HiPo manifolds. It is also a single plane style which is for higher rpm, 3500+. Engine heat will heat up a regular manifold, just takes long and doesn't get as hot under the carb only area.
Exhaust is the best place to start on the engine. Work your way backwards on a engine. If you build high rpm with a cam, manifold, carb. the heads/exhaust will chock it down and you'll be disappointed. If you build high rpms without strengthing the bottom end, you will damage it, just a matter of time, rod bolts are "VERY" weak on the 289/302 engines. Cast pistons can easily destroy your block and heads.
And then there is the drivetrain, a chain is only as strong as it's weakest link. Use a 600 holley, dbl or vacuum, with a Preformer style manifold. It'll run better, get better mileage, drive nicer, and will be fun to drive.
: I just purchased an Eldelbrock Air-gap intake for my '77 mav with a 302 and I am very excited about hooking it up. One question though, the manifold states that it does not have an exhaust cross over. Do I need that? I feel a little dumb for ordering the part and not checking first. My state doesn't have an original equipment,"under the hood" check for emmisions so if I don't need it I will be legal to install it. I also purchased an Edelbrock performer 750 cfm carb, so the combo should rock.
: The intake and carb are a bit much for the stock exhaust and heads but I plan on upgrading those very soon, one step at I time I guess.
: thanks