fastlt1

iTrader: (4)

Gonna replace head gaskets this winter on my stock 99 ls1. Thought about installing headstuds, some ported 317s and thicker head gaskets. I want to go turbo next winter. How much horsepower do you think I'll lose na with stock cc heads?

AgFormula02

iTrader: (13)

I have seen a similar swap. You will met up HP. About 15 plus or minus depending on the cam and quality of the port job and thickness of new gasket.
317s ported will flow much better that the 853s I assume you currently have.
The drop in compression from the heads should not be too bad. Do you know if the chamber cc changed with the porting?

fastlt1

iTrader: (4)

I'm looking at the prc stage 1 lq9 heads. 72cc

gagliano7

If you send the 317 heads to AI they will weld the chambers so you can up the compression or keep stock compression. And if you have them ported you will basically have 243 heads ported.

omc8

iTrader: (7)

317 stock chamber is 71 cc . How much does ai charge to weld up the chambers

gagliano7

Not sure you would have to call them but i want to say $200.

z-maro

iTrader: (18)

$200 sounds about right. I bought a set of AI 232cc 317's with the chambers welded up to 62cc from a member on here and have a copy of the invoice somewhere.