Hi all,
Has anyong out there ported their stock manifolds rather than buying headers? A guy that lives around here told me to do it and says the power gain is about the same. Can it be done? How? And is it worth it?

 

Sure, it can be done, but since the factory manifolds are log shaped it would be difficult to get all the way up inside them to fully port them. But you can smooth out the casting inside and that will help flow. Make sure you use the TPI manifolds with the 2 1/8 ( or 2 1/4 not sure about size ) outlets, the TBI manifolds would be a waste of time. Same power as headers? Probably not, but its cheaper and it looks stock.

 

might want to look into starting off with LT1 manifolds. Get the connection to the stock LT1 Y pipe and put it on yours

------------------
-Tas
'89 Formula WS-6

305, TBI, 700R4, P.A.W. 14x3 open element with K&N, Milodon 160* thermo, functional Formula hood, cross-flow Flowmaster, '99z28 rear pipes and tips, Hooker 1-5/8" 50 state legal headers, Dynomax 3" I pipe (PN 44063 and 43248)
Super GRK_Taz World
F-Body Dual Exaust
EFI & Intake Options

 

What is there to port? Practically nothing, and no you wont gain anywhere near putting headers on. Especially since you're removing the manifolds, why put that crap back on. Just get headers. You'll be happy you did.

------------------
1991 Camaro Z28
5.7L 5-Speed (originally 305)
317 RWHP, 418 RWTQ
13.23 @ 107.62 MPH (2.10 60')
Southern California
Member: SoCal 3rd Gen F-Bodies
Member: SoCal F-Bodies
-=ICON Motorsports=-

 

I have to agree w/ kevin. I swapped to the big outlet manifolds/dual cats just to see the potential of the set-up before i put headers on it. I was planning on doing some porting to the manifolds before i put them on just cuz i was bored. Well, i looked at the mani's for a few minutes and couldn't for the life of me find anything worth grinding on in there, expecially considering how fast, easy and fun it is to port iron, lol. Basically, they are such a horrible design (log) that there isn't any flash or irregularities that seem to cause any turbulence compared to the complete anarchy that a log design causes in the first place.


------------------
Ed Maher - Moderator @ The TPI & Carb Boards
92 Z28 Convertible - Quasar blue / Tan top
305 TPI A4 2.73 - 14.7 @ 93.6
Stock except ported plenum and dual cats
-=ICON Motorsports=-

- Definitely prototypes, high powered mutants of some kind. Too weird to live, too cool to die