Which top end makes more power on this engine......?
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Which top end makes more power on this engine......? Engine: 390ci GenIV at 10.2:1 cr
Cam: 234/234 .621/.604 115+4
1 7/8" LTs
4L80E
PRC 227cc CNC ported Small Bore 3.9"-4.0" ((((with a ported LS6 intake and 90mm TB)))
Flow: .650" 330 CFM / 236 CFM
199-SSPRC227CNC PRC 227cc CNC Ported Small Bore 3.9"-4" Cylinder Heads (texas-speed.com)
or
Go RECTANGULAR PORT:
PRC LS3 Aftermarket 260cc ((((with an LS3 intake and 90mm TB)))
Flow: .650" 372 cfm / 240 cfm
199-SSPRC260LS3 PRC LS3 Aftermarket 6-Bolt 260cc CNC Cylinder Heads (texas-speed.com)
Cam: 234/234 .621/.604 115+4
1 7/8" LTs
4L80E
PRC 227cc CNC ported Small Bore 3.9"-4.0" ((((with a ported LS6 intake and 90mm TB)))
Flow: .650" 330 CFM / 236 CFM
199-SSPRC227CNC PRC 227cc CNC Ported Small Bore 3.9"-4" Cylinder Heads (texas-speed.com)
or
Go RECTANGULAR PORT:
PRC LS3 Aftermarket 260cc ((((with an LS3 intake and 90mm TB)))
Flow: .650" 372 cfm / 240 cfm
199-SSPRC260LS3 PRC LS3 Aftermarket 6-Bolt 260cc CNC Cylinder Heads (texas-speed.com)
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But N/A or boosted…….why wouldn’t the better flowing head always be the choice? Air in….air out as fast as possible, right?
Roll racing will be the race of choice…..and 1300 RWHP with the turbo I’m using is the power goal.
Last edited by BigBoyWS6; Jan 24, 2024 at 03:49 PM.
I don't think you'd really be taking full advantage of the PRC rec port heads with that cam. If you want to run those heads I'd step up cam and to a short runner intake. The cathedral port setup would definitely benefit from a FAST 102. I wouldn't waste my money doing the TPIS 90mm throttle body, put that toward a FAST.
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I don't think you'd really be taking full advantage of the PRC rec port heads with that cam. If you want to run those heads I'd step up cam and to a short runner intake. The cathedral port setup would definitely benefit from a FAST 102. I wouldn't waste my money doing the TPIS 90mm throttle body, put that toward a FAST.
And that will be optimal staying with my current cam……for the turbo set up also?
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From: Carnation, WA
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Two things made me go that way. I think the single pattern cam will exhale easier on a cathedral port head because the I/E flow ratio is better. That head would also give you better port velocity and snappier response just driving around. The cam being relatively mild made me think you had street manners in mind.
Forced Inductions. FORCED INDUCTIONS V5 BILLET S491 CRC 102 TW 1.32 A/R T6 Housing
If I need a cam change because of the heads and to have a better turbo cam, I'll change it also.
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well, maybe I started the thread out wrong. I was always told to make as much RWHP as possible, then go ahead and boost it, and you will make more power boosted in the end.
I ultimately want the best head that will fit best for boost, in the end. I plan to spin it to 6800.
I want to do this upgrade now. Along with a new intake and TB to match. I was told a 90mm TB is all I need for boost. Of course, if I need a better spec’ed cam I’ll go ahead and do it, even though this cam is brand new.
If you are going boosted with the healthy turbo don't even worry about trying to make MORE POWER below 5000rpm. That turbo will make more power than you can use once it makes boost for the most part until you are in 1:1 gear. I have a Precision 88mm T4 on a 376ci setup running MAST LS3 heads, LS3 intake and I can't even use the power until 4th gear ramping it in by boost/time in each gear (T56). The LS3 intake is a great intake for boost. I've spun it as high as 7800rpm even though it hits an airflow wall just under 7000pm... it will carry the power... it just starts to fall off. I would keep shift points under 7200rpm if you aren't using big $ lifters for a long an happy valvetrain life.
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From: USA
Engine: 390ci GenIV at 10.2:1 cr
Cam: 234/234 .621/.604 115+4
1 7/8" LTs
4L80E
PRC 227cc CNC ported Small Bore 3.9"-4.0" ((((with a ported LS6 intake and 90mm TB)))
Flow: .650" 330 CFM / 236 CFM
199-SSPRC227CNC PRC 227cc CNC Ported Small Bore 3.9"-4" Cylinder Heads (texas-speed.com)
or
Go RECTANGULAR PORT:
PRC LS3 Aftermarket 260cc ((((with an LS3 intake and 90mm TB)))
Flow: .650" 372 cfm / 240 cfm
199-SSPRC260LS3 PRC LS3 Aftermarket 6-Bolt 260cc CNC Cylinder Heads (texas-speed.com)
Cam: 234/234 .621/.604 115+4
1 7/8" LTs
4L80E
PRC 227cc CNC ported Small Bore 3.9"-4.0" ((((with a ported LS6 intake and 90mm TB)))
Flow: .650" 330 CFM / 236 CFM
199-SSPRC227CNC PRC 227cc CNC Ported Small Bore 3.9"-4" Cylinder Heads (texas-speed.com)
or
Go RECTANGULAR PORT:
PRC LS3 Aftermarket 260cc ((((with an LS3 intake and 90mm TB)))
Flow: .650" 372 cfm / 240 cfm
199-SSPRC260LS3 PRC LS3 Aftermarket 6-Bolt 260cc CNC Cylinder Heads (texas-speed.com)
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I had to get my car on the road. Picking it up today at the shop who did the install, towing it to my tuner, with my new engine done and ready to street tune it tonight.
My engine was assembled using my old heads. LS1 ported, old as dirt, flow 304@.650. I couldn’t stop the install till I found new heads.
This same shop is going to install my T6 Huron Kit. Hopefully in just a couple months. I’ll have him do the head swap, LS3 intake and TB.
Im pretty sure im going LS3 style. Still trying to make a choice.
Ising a compression calculator O think it was right around 10.2:1.
My engine was assembled using my old heads. LS1 ported, old as dirt, flow 304@.650. I couldn’t stop the install till I found new heads.
This same shop is going to install my T6 Huron Kit. Hopefully in just a couple months. I’ll have him do the head swap, LS3 intake and TB.
Im pretty sure im going LS3 style. Still trying to make a choice.
Ising a compression calculator O think it was right around 10.2:1.