Brandon Smith

Ok i have my LS1 in my 67 up and running and I have the stainless works LT's up there and I was wondering on ideas for the rest of the exhaust. I really wanted the Magnaflow tru-x system in a 3 in but I have some telling me that they think that it will hurt hp without enough back pressure and think i should do the 2 1/2 inch tru-x system. Without the stroke the motor with heads and cam and bolt ons put down 44x RWHP so stroked i am thinking 48x or 49x and thought the 3 inch would be better for helping a motor like that out. Suggestions?

Shawn MacAnanny

iTrader: (12)

Large cams don't need backpressure to maintain torque. The x pipe is also an excellent source of torque. You would see gains of something like 15rwtq going from a true dual to an x pipe setup. I am running a 3" x pipe setup and having it exit right before the rear tires.

Brandon Smith

So I am guess the 3 inch exhaust wont fit over the axle and there is not enough clearance? And are you running mufflers with it?

Brandon Smith

Not a huge cam either it is a F13 cam and if i remember correctly it is like .595 .595 or close to that not over .600 but eventually plan on going bigger

Navy Blue 01 B4C

iTrader: (4)

If your putting down almost 500hp, three inch would be the way to go. Flowmaster makes one piece three inch mandral bent tail pipes that fit very nice. Use good flowing 3 inch mufflers and the 3 inch x pipe and you will have a great flowing system.

Brandon Smith

So the back pressure thing is not going to be a problem?

Old Geezer

iTrader: (3)

blowing hot exhaust up your...
The idea behind hi flow systems is to minimize back pressure.

SMAX

iTrader: (11)

While large exhaust can be over kill for some engines, needing back pressure is a myth.