2005 silverado rcsb- Made 300whp mustang dyno on a tsp 216 220 550 lift truck has no cats but stock muffler and a k&n intake.

looking to do a ported throttle body and muffler how much are the gains from that.

What are the little other things to bring power up

 

Headers

 

Do NOT port the throttle body.
do a nnbs intake and 87mm tb.

 

Headers and probably a better flowing muffler

NNBS intake and 87mm tb is the ticket.

 

a. Do not port the throttle body.​​
1. Long tube headers.
2. NNBS intake manifold.
3. 87mm Throttle
4. I'm not 100% in agreement that the muffler is absolutely necessary

 

I just don't remember the flow numbers on a stocker. If people say Flowmaster is bad I can only imagine a stock muffler lol


Also HEADS. You need HEADS.

 

I made 477 thru the entirely stock exhaust system. It flows ok imo

 

Naturally aspirated?

 

hahaha wouldnt that be the business!!

12psi, Procharger P1 at 6700 rpm

Edit: only other mod was LS9 cam (straight up) and LS6 springs

I then advanced the cam 4°, made basically the same power (472) and said this cam is stupid and went with a 212/218 but never dyno'd that combo before I pulled the blower off to rebuild

Straight NA with FBO and 3.5" exhaust truck makes 302

 

So my point is, since the original poster is so easily influenced (ported throttle body), we need not confuse him with an argument about flow rate of stock manifolds versus the scavenging of headers. While I understand you are talking about the flow rate of your muffler, you worded your post in a way that makes it seem like headers versus stock manifolds is not that beneficial.