317 heads - good to port & polish?
08-17-2016, 11:33 AM
#21
Yeah, I don't know that I trust myself enough to go screwing around with a dremel on my heads. More power to ya if you're skilled enough though!
I guess I wasn't sure if it was even worth the trouble or money. I'm hoping for 525 - 550 RWHP with the 317's, LS6 cam, and MPT70 turbo. In the grand scheme of things, is a P&P job going to net enough extra HP to make it worthwhile?
I guess I wasn't sure if it was even worth the trouble or money. I'm hoping for 525 - 550 RWHP with the 317's, LS6 cam, and MPT70 turbo. In the grand scheme of things, is a P&P job going to net enough extra HP to make it worthwhile?
For your goals it's a waste of time/money/effort to port (or have ported) the 317's. Can easily make more than your goals on an untouched casting. Spend the money elsewhere IMO. Look into an S475 or similar turbo instead of that crappo MP70.
I'm easily making around 1000 crank hp on an untouched 317 casting and 18ish lbs of boost with a mild cam. With boosted engines you don't need fancy port work or high RPM.
08-17-2016, 11:45 AM
#22
For your goals it's a waste of time/money/effort to port (or have ported) the 317's. Can easily make more than your goals on an untouched casting. Spend the money elsewhere IMO. Look into an S475 or similar turbo instead of that crappo MP70.
I'm easily making around 1000 crank hp on an untouched 317 casting and 18ish lbs of boost with a mild cam. With boosted engines you don't need fancy port work or high RPM.
I'm easily making around 1000 crank hp on an untouched 317 casting and 18ish lbs of boost with a mild cam. With boosted engines you don't need fancy port work or high RPM.
08-17-2016, 11:57 AM
#23
Restricted User
Your long block doesn't care that you're feeding it more boost. Feed it whatever it takes to reach your goals.
08-17-2016, 12:01 PM
#24
I’ve also found heads are likely to be damaged if/when an engine fails. I’m glad I didn’t have lots of time and money sunk into my heads, as they were beat up badly when the engine failed. I picked up another set of 317’s for $120. Cleaned them, lapped the valves by hand, and installed my springs…done.
I understand you're a race head guy... but the OP is talking 525 - 550 RWHP... Thats nothing on a boosted LS of any kind.
08-23-2016, 06:26 PM
#25
I just know I pro charged a 05 lq9 with 317 heads .. I'm guessing 10:1 and a 03 Zo6 cam .. tuner said it choked at 5k rpms making 350hp and 400tq with 100% .. asking for a safe tune .. my brother has twin turbo at 7 pounds also with a ls2 and 317 heads running 9.5:1 100% gas and maxed out the 60 pound injectors a little over 700hp .. so I at least know them heads can flow 700hp , just not sure what my problem is .. porting heads help that much? or the cam? .. he's even running less timing that I am .. kinda baffling to me
08-23-2016, 08:15 PM
#26
I’m all for that if budget isn’t a concern. Looking at cost VS HP you already bought the turbo and turning up the boost **** is free. If you can meet your power goal on boost alone (easily in the OP’s case) then why spend money on porting the heads?
I’ve also found heads are likely to be damaged if/when an engine fails. I’m glad I didn’t have lots of time and money sunk into my heads, as they were beat up badly when the engine failed. I picked up another set of 317’s for $120. Cleaned them, lapped the valves by hand, and installed my springs…done.
I understand you're a race head guy... but the OP is talking 525 - 550 RWHP... Thats nothing on a boosted LS of any kind.
I’ve also found heads are likely to be damaged if/when an engine fails. I’m glad I didn’t have lots of time and money sunk into my heads, as they were beat up badly when the engine failed. I picked up another set of 317’s for $120. Cleaned them, lapped the valves by hand, and installed my springs…done.
I understand you're a race head guy... but the OP is talking 525 - 550 RWHP... Thats nothing on a boosted LS of any kind.
