alright. before i go off the deep end and sink money into the motor of this car.

here is some back ground
05 GXP
ls4 motor
5.3 base
243 heads
baby cam {smaller then the 97-00 ls1 stocker}
9.9 c/r

plans thus far.

1.85 rockers
push rods, blah blah blah
now, i was looking at the patriot 59 cc heads to get a jump in c/r on this motor.

im not looking for massive gains, like 50-100 hp. that doesn't concern me.

so far it seems a battle between
patriot
afr 205
edlebrocks {i can get these through my work}

pros and cons of each. or just port the stock 243's and call it a day?

im staying with the stock cam. no way around that.

looking for about 10.8-11.0 c/r
tuning isn't a problem

my main goal is to get it to breathe better up top, it falls on it's face about 110 mph.

any help would be much appreciated

 

IMO ported, maybe decked heads

 

For curiosity's sake.. why are you sticking with the stock cam? Those 243 castings will flow so well with even a 224/224 cam with a moderate lift.. you're leaving so much on the table with the stock cam in that car. Is it because of the DOD?

Anyways, I would have your stockers ported and decked, to bump compression and increase flow.

 

well, because it's a bitch to change the cam in the car.
hence the 1.85 rockers to help out a bit.

you have drop the motor and tranny cradle, the front cover that houses the water pump, ps, and other things is one piece. basically a big ole bitch to change it.

plus, i like being sneaky.

300 whp will put me in the high 12's nicely, and im not too far from it right now actually.

whats different from the patriot 59cc heads vs the ported and decked 243's?
i thought they used 243 castings, just a cnc port job and 2.02 1.57 valves?

 

you better have a friend that can rebuild GXP trannys

 

If theyre anything like the.. 4t65e that was in my GTP then he should have no problem with 300whp all motor (assuming around 320wtq, maybe?). I had a shiftkit and stock internals on my 97 and it shifted fine, original trans and a shift kit on the hardest setting. I kept the line pressures at stock though. I had a pulley, and an alky setup with a 3" dp and all other supporting mods. Never dyno'd, but I was estimating about 260whp and about 340wtq (s/c'd). Im pretty sure those trannies are good to the levels hes looking to go to.

 

i have already had 370 ft lbs to the tire.

the tranny is fine for 300 fwhp.

the car did 255 stock
i know it's not ls1 power, but it's still a half *** family car.


so, the majority seems to think the stock 243 heads would be best if ported and thrown back on?

no patriot? too big perhaps?

i was more or less going for the 59 cc chamber more then anything else

 

For starters the 59cc PP heads you're talking about are 6.0 heads, not 243 casting.
2.02/1.57 would be a big waiste of time.
You have 3 options:
1- remove yours, have them CNC'd by PP and keep the stock valves. Upgrade to LS6 or 918 springs
2- AFR heads milled to bump your compression
3- Edelbrocks

1 question though, can you tune this car?

 

tuning isn't an issue.
the 59cc heads are milled down 243's which is what is on the car now.
anyone else runnin the edlebrock heads? or is it a waste of time for out of the box fun?

may do some diggin around town here and see if i can come up with a set of 243's to have lightly done