Bronson Bentley

I'm Building a LQ4 wiseco -11cc forged pistons K1 6.125 rods. Howard's Cam 625/625/ 234/236 112 LSA cam (Just one i had laying around can be changed)
LS6 Intake and untouched 243 heads. Im trying to get to the 480-500 whp mark N/A. then future plans are two stage wet kit. my question is should i sell the 243's then use LS3 heads to get to my goal? or mill my 243's down and run them? if the 243's are to be used how much do i need to mill them to get to a good compression ratio mean i'm currently at 9:7:1 with the untouched 243's

HCI2000SS

iTrader: (2)

It's gonna be really tough to get 500 rwhp with 243 heads IMO. Depends on the dyno of course

Bspeck82

If you can run ls3 heads id do that. Maybe if you work the ls3 heads over then you might see 480 tire...I strongly advise looking for either aftermarket ls3 style heads or port the ls3 heads if you got em already. (But of you want to leave them stock then by all means they are great! Id at least get a valve job) If you dont reach the numbers don't sweat it, dynos very greatly and if you want an accurate measurement of horsepower then run it at the track. I wouldnt even bother caring about dyno numbers, I know it will make power. Id call the cam vendors about what cam would work best. For cathedral heads that cam is perfect, for rectangles, you may want something else but again ask them.

NAVYBLUE210

MMS 235s with the NFI (nitrous/forced induction) exhaust
Port and ported FAST 102 should reach 500 RWHP with
At least 10.5:1 comp (11.0:1+ Preferred) with your cam
In M6 pretty comfortably. Would not need to change cam
With that exhaust port till 200+ N2O with at least
1 7/8" Headers. The MMS 235s are the Best Cathedrals
And will out perform stock, ported, and Aftermarket
LS3 Heads, on street/strip cars below 400" and/or 7000 RPM.
Check out what MMS235s did on a blown 416" in the
Dyno Results section.

Darth_V8r

iTrader: (4)

Yup, I'd run the MMS235, sompression 11.5, ported MSD airforce, supporting mods

Jakewet28

Port and mill 243's to mid/low-50s cc's, ported fast 102 or msd, thinner head gasket, possibly a bigger cam, and a good tune. You're kind of shooting yourself in the foot with -11 cc pistons trying to make 500whp, so you're going to have to try and make up for all the lost compression in the pistons but shaving the heads down a good bit.

Rise of the Phoenix

iTrader: (27)

My setup is 470+rwhp on a stock bottom end LS1. With the additional cubes, it would be very close to 500 rwhp. Mods in signature.

Tuskyz28

Darth and Navyblue..... saying the MMS 235 cathedrals are the BEST catherdral heads on the market is a BOLD statement!! I still havent seen REAL WORLD RESULTS AT THE TRACK out of the 235 MMS heads. However i seen a out the box 230 AFR go 10.60s on a 403ci.... Yes i understand Darth went 10s with a solid roller with 220 mms catherdrals.... but remember factory 241 heads have seen 10s as well on a stock cube motor with a eps hydraulic roller shelf cam.

Otherwise ill go with something that have been PROVEN over and over and never dissapoints which is some TFS 245 cathedrals with a cam to match. Also on the intake i personally would go Fast 102mm ported to heads. 500 rwhp will be a breeze and so will LOW 10s on motor. Ask me how I KNOW......

Darth_V8r

iTrader: (4)

IMO, the TFS 245 head is a great head, but is too big for a 6.0, but probably ideal for a 6.2 due to the larger bore. Also, at one time, the TFS 245 was an unproven head...

The MMS 235 is to the AFR 230 what the MMS 220 is to the AFR 215. Tony designed all four heads, and in the case of the 235 and 220, made improvements. An out of the box Mamo 235 is as good as or better than a Mamofied AFR 230. Now, get the 235 mamofied, and you've got something. So, if you have track proven results for the AFR 230, you've got a worst case scenario for the mamo 235 given they are swapped into the same vehicle and run under the same conditions.

People said the same thing about track proven results in my thread and several other threads until I ran it. The 235 heads are relatively new, and eventually they will be track proven. 98_WS6_M6 will eventually back up what I got on the mamo 220, as did Firebird muscle running tens -- basically untuned on those heads. Point is, somebody has to be first. Then a few others will back it up. Then, it will be more commonly accepted. I'm quite sure that a head that performs as consistently well on dyno's is going to eventually perform consistently well at the track.

That's really impressive about the 241 going into tens on EPS cam! What are the deets? Race weight? cam durations? gearing? DA? Was it a purpose built track car or a DD like mine? There's guys who have left motors stock internal and focused on bolt ons and refining the rest of the car instead of the motor and gotten numbers better than mine -- like RobZ (Vetteboy).

big hammer

GMPP 243's could get you there

Public Enemy

Use the BTR stage 4 camshaft, get the .040 cometic gasket, port the 243 through AI or WCCH with flow matched fast 102mm intake and you will be around 500whp. SCR should be around 11.5:1.

I personally prefer BTR TFS 220's with 62cc chambers for your setup.

gagliano7

Just remember if you shave the heads you lose PTV clearance. The LS3 heads have 68.5 cc chambers so you will lose more compression and you can't shave to much off those or you will have PTV issues. You could send the 243 heads to AI they can weld the chambers to raise your compression without losing PTV. To me the best deal for price and performance are the as cast 220 trickflow heads touched up by tooley with powdered metal guides so you can use your stock rockers.

tech@WS6store

iTrader: (2)

A flat top piston and a larger cam would get you close. Id ditch the ls6 intake and get a fast92 though. a larger bore like 4.030 would take less effort to make the power you want and not be a bunch of extra cost. a 370 with a custom cam and fast92 would get you there on the 243s. Having some work done to them like even mild porting or a better valve job/blend will help quite a bit.
You dont have to spend 2k+ on heads to make the power. if you want a good budget head the tfs220 as cast is great out of the box and gives you room to grow later also.

speedtigger

iTrader: (16)

The -11cc pistons are not a good choice for an N/A setup as far as making max power. 9.7:1 is on the weak side for an LS engine. I think a good formula would be some flat top pistons (approx. -3cc) with some CNC ported 243 heads milled down to a 59cc combustion chamber (approx. .030" milled off).

If you are trying to make 500+ RWHP, you kind of have to maximize every detail. A short cut here and save a few $$$ there all cuts in to the performance to some degree. Those sacrifices add up and you end up falling well short of the goal.

A.R. Shale Targa

iTrader: (2)

FIXED 4 YA....

speedtigger

iTrader: (16)

The OP is using aftermarket forged pistons. Most have ample valve pockets, so this will likely not be an issue in his application.

gagliano7

Thanks!

64post

iTrader: (5)

Did the OP just disappear on this thread? A lot of good suggestions here.

G Atsma

He must have..... Still shows only one post to his name in his original post.
You guys must have swamped him in too much good tech...

Darth_V8r

iTrader: (4)

Or he didn't like the answers, so "eff this place"