I found a set of 317 heads that i can get pretty cheap. I was wondering how big of an increase I could see with these heads. Set up is 4.8 with 212 216 .524 115lsa cam, Front mount 70mm turbo with 10psi right now. Just wondering if these would be worth it?
Name: Mark,
God created turbo lag so nitrous trucks could have a chance.
http://www.ls1truck.com/forums/my-ga...tml#post274877
if you're looking to run some decent boost yes. they're gonna drop your compression quite a bit.
2007 RCSB|DTR81 built LSx 3xx|PRC|NX|BOGART|MSD|QUICKFUEL 950 E85|4L80|FTI Converters|Smith RaceCraft|Racepak
midweststreetcars.com
It will be a dog off boost, but will scream when you put 15psi to light the coals!
2006 Superior Blue Trailblazer SS AWD, Stock as a rock
Sold: 2002 GMC Sportside Denali front end with a 2002 LS1, FLT level 5, Yank 2600, Trick Turbo, T76, Nelson intercooler, 60LB injectors, Warbro fuel pump, Eaton locker, Magnaflow, 3.42, Nelson Performance Tuning (speed density).
Sold: 1981 GMC LB RC 1500 2002 4.8L 4L60E 12 bolt 3.73 Richmond Lock Right AC PS Nelson Performance tuning
You will see 50+rwhp probably at same psi.
317/243 heads flow MUCH better than 862 truck heads.
flow more at .400 lift than the 862's flow at .550 lift.
Boost will also lover the bigger 2" intake valves.
243's with their smaller combustion chambers would be a better match
than the 317's.
2002 Tahoe 4.8 - soon to be turbo'd - SOLD
1989 Mustang - LX Vert - 351W-TT - 2inches of dust covering it
2012 Raptor - 497rwhp at 10psi
If you aint breaking - you aint going fast enough
i think they would compliment your new spring nicely...
01 Silverado
i thought lower compression was better for boosted applicationsOriginally Posted by r.barn
00 FRC - just top end, exhaust, and a hot-air intake
99 Sierra - 5.3 / 5spd
↓ click the pic for the build ↓
Not that much lower.
yeah but too low of a CR would cause you to run more boost to compensate for the lost power from the CR drop. stock 4.8 is 9.4cr with 61cc heads. with 72cc heads that puts the cr to what? 8.5 im guessing? You would need to run 18psi to make up for it. I dunno but 243 heads (64.4cc) would drop compression and flow better. I would get 243.i thought lower compression was better for boosted applications
gotcha.
00 FRC - just top end, exhaust, and a hot-air intake
99 Sierra - 5.3 / 5spd
↓ click the pic for the build ↓
That being said why couldn't i shave the the heads and just put a P&P job on them.
Name: Mark,
God created turbo lag so nitrous trucks could have a chance.
http://www.ls1truck.com/forums/my-ga...tml#post274877
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