VortechC5

iTrader: (6)

I currently have Livernois Stage 2 ported L92 heads on my LS7 based 428. Would there be any worthwhile gain if I were to go to something like the PRC ported LS7 heads?

See5

iTrader: (53)

Interesting question.
My guess is you will pick up some HP in the upper range due to better high rpm head flow and the use of an LS7 style intake. Also suspect you will lose torque as a % of hp. Under the curve gains?

VortechC5

iTrader: (6)

A little bit less low/mid range would actually be ok. I am making 400 lb/ft starting about 2800 rpm and that makes for no traction at all in first and sometimes in second as well.

See5

iTrader: (53)

I feel your pain.
Just not sure giving up torque or moderating pedal position is preferable.

There is some comfort in knowing you have more than you can put to the ground, but that in turn creates dilemmas regarding solutions and C5 drive train durability..

Abdullah

iTrader: (2)

i think you will gain more power with the TSP CNC 265cc LS7 heads. not sure on the torque maybe you will gain the same amount of torque as the L92 heads since i saw some ported L92 heads as big as 279cc intake runner!

why don't you try touched up TFS CNC 235cc heads with ported 92mm Fast intake manifold? they will make almost identical power to the ported LS7 heads yet will make more torque than ported LS7 heads.

Jason 98 TA

iTrader: (4)

The L92 vs LS7 wouldn't be a good comparison at all. The LS7s from what we've done have made a considerable amount more power than the ported l92 heads. The LS7 PRC heads have pushed LS7 based engines on our engine dyno to 750fwhp!

The good news is Ferrea just shipped us a hollow stem valve for the LS7 & we should have our new larger diameter valve spring to control the heavier valves here very shortly!

This should allow you to be able to build a LS7 head motor for reasonable money!!

Jason 98 TA

iTrader: (4)

I completely disagree. A 340cfm cathedral port head is just not going to support the kind of power of a Ported LS7 head that moves 400cfm.

VortechC5

iTrader: (6)

I just looked at your web site. It looks like $1799 for complete LS7 heads assembled and ready to go. True?

How much of an upcharge are the hollow stem valves?

How much lift will the supplied springs tolerate?

Sales2@Texas-speed

iTrader: (5)

$1799 covers stainless valves and no spring kit. It's an additional $250 for the PRC dual spring kit to be included. That setup with the stainless valves is good for about .615" valve lift or so (limiting factor being valvetrain mass and control thereof).

Upgrade to the titanium valves and then you're good for .650" lift!

VortechC5

iTrader: (6)

Are you planning any holiday specials?

obZidian

iTrader: (2)

How much for an exchange? I have stock ls7 heads and looking for the best ported heads I can get without dropping a fortune on them.

A.

Greg Fell

iTrader: (9)

its too bad the 400 cfm doesn't flow 400 cfm in the real world. Bolt a manifold on the 400 cfm head and presto...no longer 400 cfm head. Same goes with the 340 of course, but from what I've seen the TFS make more power under curve and result in lower ET's.

I'd love to see independent dyno graphs however, always looking for more power. I can tell you I've had both top ends and the tfs is a lot more fun and faster sub 6500 rpms.

fwiw i think the ls7's would be the ticket if you spun them up higher than most people feel comfortable spinning hydraulic roller cams. that usually means ditching the plastic intake and the going solid roller/sheet metal.