well here goes

Spoke to more than a few throttle body porting professionals and they all think I might not gain any horsepower by swapping my stock 87mm throttle to a ported 90mm on a 750HP supercharged 427 truck?

Others think I will gain nothing by swapping out my single 3" y-pipe to a true dual 3" + xpipe.

Both of which dont make any sense to me. The norm seems to be about 400hp before a single 3" becomes a restriction, and Corvettes for one use dual 3" pipes on Z06's and ZR1's.

Help before I loose my mind, and money

 

To heck with the nasayer's and just do it

 

Only way to really know is somehow get a pressure reading behind the TB and see if it is below atmospheric when you go WOT. The 87mm is already pretty damn big.

 

Definitely do it anyways if you're wanting to.

Aren't the stock truck ones 78mm or something like that? Or are the nnbs bigger? And I imagine even the 3mm would make a difference, as porting seems to grab a few hp on a stock motor, much less a S/C one.

Same for exhaust, I think you're right, it would be wrong to say youl'll make NO gain, but I don't think itll be anything huge, but every bit helps

 

If we all listened to the people that said this or that mod would not make a difference, then we would all have 15 second trucks and think we are fast. Do some more research and find out what you are willing to risk for nominal gains.

 

im not making near the hp you are. im about 360hp and going from the stock 87mm to a 90mm made my truck run better. im not talking about 10+ hp or anything but with my cam the stock 87mm would sometimes take 2 times to try to crank my truck and after switching to the 90mm it starts right up. so it needed the extra air.

 

I'd put a 102 on that thing and never look back. What intake manifold do you have on it?

definitely do a dual 3" system and leave out the X pipe. the scavenging BS is just that... If anything, do an H pipe or nothing at all. 1 7/8" long tubes and free flowing dual 3" exhaust are a must on something like what youve got.

 

Sounds right, i still think the x pipe would be a good thing to have not too sure though.

What 102 throttle do you have? Also hows drivability with that throttle?

Truck has 1 3/4 highflow cats and a single 3" ypipe talk about exhaust restriction on this motor...

 

My truck is manual throttle, not drive by wire like yours. I'll be running a 95mm on a stock displacement setup.

I'd seriously look into a 102 for yours though.

 

How is an x pipe bs? I remember a couple years ago on one of the mustang forums I frequented a guy had a set of cutouts on his x pipe. He dyno'd the car with the cutouts open, open headers and then dyno'd the car with them closed and actually lost power with them open because of the lack of scavenging.