Originally Posted by theguesswho
hi i have a 73 riviera with an all stock buick 455 and its true duels with no cats, i was just wondering if i we're to put a cherry bomb glass pack on each each side where a catalytic converter would go on your avarage car and ran straight pipe all the way back to the back bumper would i have any back pressure with the glass packs being where they are?? or do glass packs even give backpressure in the first place? iv heard they do and they dont. and would that give me any increase in horespower at all? and to anybody that has done this befor, did it sound good?
Couple things for you to consider.
Don't worry about back pressure. There will be some backpressure if you run a full length exhaust system, even w/o any mufflers. Some glass pack style mufflers have a lot of backpressure, so do your research before buying. The Walker Dynomax turbo style mufflers get good reviews.
Putting the mufflers (regardless of the type) as far rearward as practical is the best choice.
Connecting the two sides w/a length of pipe about the same diameter as the pipes it's connecting to will give (what most consider to be) a better tone to the exhaust, and can help prevent that *rapping* on deceleration.
A set of long tube headers will help more than what type mufflers you use. Unfortunately they may be hard to find.
Feeding the engine cold air from outside the engine compartment can help performance.
A properly set up HEI and a good thorough tune up will be as much of an improvement as most anything you can do short of a cam, etc.
is a page on the HEI.