Gannet

I'm looking at using the GMPP LSX-LS7 heads on my build.

Does anyone know the spring spec for the supplied ".650" beehive springs?

Does anyone know if they are available as bare castings, and if so, what the part number is?

SMITHBERG RACING

I believe they use a PAC Spring don't remember the part #.
They are cut for a 1.550 spring pad to go with a larger spring.
I'm sure you could get them bare. The package deal is hard to pass up, sell off what you don't use. I think they are $2600 assembled pair. I have a pair at my shop right now.
https://ls1tech.com/forums/generatio...here-sdpc.html

Beau@SDPC

iTrader: (14)

They are not available bare at the moment. Prob later on this month or in march.

Jason 98 TA

iTrader: (4)

We've flowed a few sets of the out of the box LSxLS7 heads. They move about 335-338cfm at .700" lift. The PAC springs are the .650", but I'm not sure what they're rated for on the LS7 heads. Give Scoggin a call them will know. They also offer a cnc ported version for guys looking to go closer to 400cfm

Gannet

335 is that all? I would have thought they would flow like stock LS7s.

So when are the PRC versions going to be ready?

Stang's Bane

iTrader: (22)

They are cast heads, no porting work done, so that ain't too bad..

DE_VETTE1

These heads will flow enough to make more power than 90% of people use.

XxXTransAmXxX

iTrader: (12)

To my knowledge the PRC head is out. Texas Speed just had a thread regarding the new 6 bolt per cylinder thread. Unveiling and UNBELIEVABLE price outright on them or the LS7 casting. Although I may be wrong here is the link to the thread. https://ls1tech.com/forums/generatio...available.html

I woulda thought the LSX head would flow like a LS7 head even though it is a "cast version of the LS7 cnc'd runner"

Richard@WCCH

iTrader: (3)

We've ported a number of sets already. They flow as advertised from GM. Jason's results are similar to ours on the stock castings. They flow darn near what the factory heads do till just past .400" lift. Suprisingly we saw just over 300cfm @ .400" lift. Very similar to the factory ported heads. Then they nose over. We found the flow peak on the intake side to be at just over .500". The intake ports peaked flow at 334cfm. The exhaust ports peaked at 218cfm at .700" lift. We tested a number of ports on different castings and found them to be reasonably consistent considering they're cast finished. No questions they can definitely do with some port work.
Other pluses are the spring pads being machined for 1.550" springs. The pad heights are .050" further from the valve seats meaning you need to account for this when you shop for valve springs to match your application. The supplied beehive springs are a bit on the soft side.

Richard