What to do for exhaust?

Lets say i have a thumper cam kit which has tons of duration and overlap. If i ran 2 1/2 with x pipe and flowmaster mufflers would that x pipe actually hurt me? If i dont have enough back pressure with all the overlap that cam has wouldn't my intake air/fuel go right out my exhaust since the x pipe is helping scavenge the exhaust gas out? Would i be better off just gettig a regular dual out with good mufflers?

 

The flowmasters will hurt you more than the X pipe will. Run the X pipe.

 

i've actually been told by a few performance shops flowmaster is garbage. all it is is sound, doesn't flow due to tons of baffles to make that sound..been told to go with magnaflow. borla, ect..but if you already got it use it. and yes i would use the X pipe.

 

You actually want good scavenging of the exhaust so the incoming fuel/air charge isnt contaminated by the out going exhaust gasses.With a fat cam (lots of overlap) good scavenging will help keep the velocity up in the ports (you lose velocity with lots of overlap down low) Of course this helps velocity on the top so you dont get alot of reversion. Do use an x/h pipe...

 

the X-pipde wont hurt you. it will actually help you

the x-pipe might actuall smooth the cam lobe out a bit

 

2-1/2 inch pipes are on the large size for a 302 engine IMHO.

 

i'd go atleast 2in..perhaps 2.25

2.5 would be good for a 351 or a moderate built 302

 

Mufflers?????....I don't need no stinkin' mufflers..

 

Can u have to much scavenging tho?

 

Is this a street car or race only???

 

This is a street car

 

Definitely run 2", unless you want smaller pipe to give you the old school machine gun sound.
Flowmasters,magnaflows, and pretty much any muffler with baffles is restrictive and just imitates a loud engine.
X Pipe and glasspacks will give you the best exhaust flow and backpressure.

 

Are you running stock heads??? A power adder (turbo/Nitrous) If yes to the first and no to the second...Dont worry alot about scavenging the exhaust. Your engine wont have the VE (volumetric efficiency) for it to matter enough. You should be more concerned with the engines street manners and cooling system efficiency. Hope you plan to run some gears with that cam.

 

I got flowmasters and a bassani x-pipe on my car with a torker-II cam and love it,sound

 

Where'd you learn all this ? Spending the money to do a full exhaust, is pretty much pointless to do it in 2" pipe. As for the second sentence, that's only true with Flowmasters. And the third ? Glasspacks are about the worst as far as restrictive goes.