Currently im running a 305 TPI with 58mm TB, SLP runners, simmiesed plenum runners intake, world products 305 heads, comp cam w dur@.050 218/226 and lift 492/512 with 1.6 roller rockers, SLP 1 3/4 headers, underdrive pulley, no smog or egr, all free mods... but stock 2 1/4 exaust with gutted cat and 80 series flow.

Now the thing is that i want to do my exaust once and do it right... but i want it to be capable of handling a 400 w/ 210 race port AFR's, healthy cam and a pro charger

Thanks for you sugestions
JJ

 

that four inch single system will handle about anything you throw at it.

 

But I would lose a lot of low end TQ by going with the 4".... thats what it says on mufflex's site thats why i cant decide if i want a 3 1/2" or a 4"

 

unless you are making the power now do not do it. save exhaust for one of the last things if you can't afford to adjust as you go. i lost alot of low end tq with my 4" setup on my old 383 motor. it was only around 400 at the crank though. get your motor together with some true hard rwhp numbers before you go wasting your money.....you'll be sorry otherwise.

if you can actually use that size then by all means go for it. i love the sound of my spintech and with the new motor i can't wait to hear it. 4" is too much though unless your down in the 11's.

 

You didn't visit Mufflex's site. You will NOT lose low end torque by going to a larger after cat pipe. It's a myth, regardless of what others say. Visit this link to Mufflex's site: http://www.mufflex-performance.com/faq.html#q4 That's on an LS1 car, but the results would be similar for your car. I have a very mild SBC pushing 270rwhp and I gained low end torque by upgrading from a 3" to a 4" pipe.

 

wow i dont know that thanks... but i still dont know if i should go 3 1/2" or 4"

... Right now im leaning torward the 4" because if you gained TQ and thats pretty much what i have.. we'll see... nothing sounds better than a 4" :hail: in my opinion

 

I have a 3.5 inch system on my 550+ hp LS1. 3.5 will be more than enough for your setup.

 

I'm sure the 3.5" would be fine...that 4" sounds tempting though with those heads and the blower.

 

I completely agree, it's definitely a myth! You just don't see that many 'Mustangs' trading in their 2.5" true dual exhaust (totaling 5 inches), for our much more restrictive Y-Pipe configuration and it's mostly single 2.5" through 3.5" pipe design.

I say go with the 4" set-up, especially if you're planning on adding some boost.