Help me pick the best aftermarket Heads
 

In combination with my new Cam I'd also get a set of new aftermarket heads. Since I just go for a very mild "stealth" cam I want to get the most out of my Cam/Heads combo.


My new cam: 218/229 .600"/.600" 117.5


So which of those heads will fit my cam best / will show the best gains?



Update: I just ditched the GMPP heads. According to 3 independent flow tests I found, the advertised numbers doesn't seem to be reality.

Flow Specs (advertised):
 

LIFT..........INTAKE........EXHAUST


Texas Speed:
68ccs / 10.8:1 compression

.200............154............117
.300............221............170
.400............281............205
.500............325............225
.600............354............235
.650............358............240
.700............361............243


Lingenfelter
89ccs / 11.0:1 compression

.200............158.............116
.300............230.............161
.400............282.............201
.450............302.............213
.500............322.............220
.550............340.............226
.600............350.............231
.650............358.............234
.700............344.............237


Livernois

.100...........71.9...........51.8
.200..........157.5........105.3
.300..........220.4........154
.400..........263.4........196.2
.500..........308.3........223.1
.600..........346.6........232.5
.700..........357.8........237.2
.800..........359.9........245

I voted for the GMPP. Of the choices given they are most likely the best bang for the buck and with your cam you could probably have them milled for a bump in compression.

Yes the GMPP costs definately less than the others. The thing I just dont get is that according to the flow specs the GMPP heads seem to flow best - so why do the other heads cost more although they dont flow as good as the GMPPs? :iono:

I have the GMPP CNC heads on my car and had them flow tested before install. http://img.tapatalk.com/180e51b3-bd9e-65d4.jpg

http://img.tapatalk.com/180e51b3-bddc-585e.jpg

your heads for flow great. A little porting to reduce flashing is a big bang for the buck.

I think you'll get tired of that cam fast and pay for labor to have a larger cam installed and another tune.

If you want "stealth" go FI and love the car.

Take a look at Land Speed Performance / Street Smart Heads before you buy anything else. I own a set and they are going to be installed with an EPS 222/226 .597/.605 lift 115 LSA in a G8 GT Auto 6 Speed in a couple of weeks.

Many are making the mistake of buying LS3 heads with intake runners ported too much and loosing torque and power. Look at the intake runner sizes on Mast Med Bore, PRC 250CC Aftermarket, & Landspeed Street Smart II CNC heads and you can confirm what I'm talking about. The runner size is smaller to keep the air velocity up and still flow good CFM.

Looks like the GMPP heads flow much better without the really aggressive lifts so to me I would think that would make life much easier on the entire valvetain.

Also keep in mind the max lift on a GMPP CNC head is 550. After that you need to change the valve springs.... So take that into you figuring cost out.... I good set of valve spring could run you anywhere from 250 - 1000 plus install.

:) hope that helps!

P.S. Lingenfelter has patriot gold valve springs with a 650 max lift on sale cheaper then anyone else.... :)

Yes - this is what I like about the TSP PRC heads. They flow like the ported GM LS3 castings, but through a 12cc smaller than stock intake runner. This equals more velocity.



I just have two questions:

• TSP claims they laid over the valve angle slightly which helps to get about .040" better than stock piston to valve clearance. Doesn't this new angle put more stress on other parts?

• They are offering 60-68cc Chambers. Which number do I have to choose to get the most gains in combination with my mild cam?

OP

I can answer your first question about the valve angle.
The improved valve angle provides better piston to valve clearance, allowing for larger cams.
Also the relocation of the valves offers better air flow.

Hope this helps.......

Thanks for chiming in G8RAM - so the improved valve angle doesn't have any downsides? So not more risk for failures than with the stock valve angle?

bump:

• TSP claims they laid over the valve angle slightly which helps to get about .040" better than stock piston to valve clearance. Doesn't this new angle put more stress on other parts?

• They are offering 60-68cc Chambers. Which number do I have to choose to get the most gains in combination with my mild cam?

OP

If there is a downside to a better valve angle I don't know what it would be?
There are other after market heads that have been modified the same for sure.