Justinrst

I heard the 317 71.06cc heads are good if you are really running boost like 15psi or more. The 243 64.45cc heads flow the same as the 317 heads still lower compression but not too bad. Probably gonna port which ever heads I decide to buy. Which heads would you put on a 4.8 turbo truck??

The truck will be a daily driver 2wd rcsb t56 6 speed. Custom turbo cam, matching springs, lightweight valve train, ls6 intake, 90mm TB, roller rockers. Bottom end will be untouched stock.

thoughts.

tarinitup

iTrader: (11)

Whatever foose04 has seems to be doing great.

03regcab sierra

iTrader: (7)

I ported n milled my stock heads. 9.8 cr but i dont plan on doing more than 15-16# with meth.

kbracing96

iTrader: (26)

Don't drop the compression, keep it at least 9.5 to 1. It will run a lot better out of boost. These motors seem to really like compression and boost!

Justinrst

My stock 4.8 heads are 61cc and 9.47 compression.

Putting the LS6 heads on which flow way better than my stock 4.8 heads are 65cc doomes. What would that lower my compression to??

9.24?? compression

TwoTonic

Not sure they'll flow all that much better-- the ports are pretty similar. The 243's CCs are a hair lower than 65cc, but drop the Static Compression Ratio to between 9.0 and 9.1. What gaskets will you run?

02'Z71ONDUBZ'

iTrader: (8)

243's are the highest flowing casting of cathedral port heads, they will be a good improvement over stock. Don't even consider 317's, they are a great boost head for a 6.0 or full race setup on a smaller engine, but would perform poor on your setup. Go with a set of 243's and have them milled close to 61cc chambers. I would also clean up the ports some before you stick them on. I would use LS9 gaskets and ARP studs if you are really planning on pushing the boost, if not then go back with ARP bolts and stock mls gaskets. SDPC sells CNC ported new 243 castings with stock sized valves and ls6 springs for $500 each, I plan on going with a set of these at some point as they are the best value in a CNC'd 243 IMO

quicksilverado

iTrader: (8)

I would not mill the heads. That would make the decks thinner and that is one of the weak points with a stock head.

1FastBrick

iTrader: (17)

I would stick with a stock size head as KB mentioned, but have them re-worked. SDPC currently offers a cnc ported 862 head that would probally work well for your boosted application and they are reasonably priced and in stock.

I am sure Beau@SDPC would answer your questions regarding there head. he installed them on his truck.


Richard @ WCCH may also be able to help you out with head options. He is supper knowledgeable when it comes to air flow and port design and he does all of his own port work Resarch and Devlopment at WCCH and also works with alot of other top names in the buissness when designing new products.

I undertand TEA has heads that might work too but they might be geared towards a larger engines.

jeffreycastgsx

For that amount of boost, 317s. Lower compression will help you keep it alive.