The Stovebolt Site Forums The Shop Area Engine Shop '59 283 LB Fleetside with 2 barrel rochester

Any better performance in going to a dual exhaust using the existing ram horn exhaust manifolds versus the standard set up of single pipe?

Any better performance (HP or mileage) switching to a 4 barrel carb (manual choke) and changing the manifold from the 2bbl?

Thanks.

Both of those will give added performance & if done right better gas mileage. If it is worth the effort & expence that is an other story.

A 283 engine at 5000 RPM has a CFM rating of 406. That's at 100% volumetric efficiency which will never happen on a street engine. 90% is more realistic, giving a CFM of 365. A 390 CFM 4 barrel would be just about ideal- - - -anything bigger is stupid. Dual exhausts give you twice as many pipes and mufflers to rust out.
Jerry

Jack,

Here's an interesting article that addresses your issue:

http://www.mopar1.us/engine3.html

It also covers the actual performance gains from headers and a balance tube ("H" pipe) between the exhaust pipes.

The performance gains from a balance tube has been known to drag racers since the 1960s. An added benefit to a daily driver is that a balance tube makes the system quieter.

Some may say that tube headers leak. That has not been my experience. For example the "shorty" tube headers on my sbc powered street roadster were installed in 2003, don't leak now and never have. The bolts at the exhaust ports did have to be tightened a few times when I first drove it as the gaskets compressed. Not being a professional mechanic I don't know if the use of Edelbrock aluminum heads had anything to do with the bolts needing to be snugged down. These were not any kind of special gaskets, just the ones that came in a Felpro engine rebuild gasket set.