Amwellls1

Here is the deal, I have a set of 235 trick flow cathedral port heads and a ported fast 102 laying around from another build. Thinking about throwing them on my 2012 GS. Details on current set up are as follows:

2012 GS M6
Cam only G6X3, heads/intake stock
LG 1 7/8 with stock npp
4.10 gears

440rwhp on mustang Dyno
Runs consistent high 10s @ 125 to 128 range @3500lbs race weight

Appreciate any thoughts, experience, or advice on whether this is a good idea or not.

JayplaySS2

G6X3 flat works with TFS 225's so with the right compression it should be a great combo-

Amwellls1

That's what I am thinking also, seems like it's more of a 225s on a ls2 thing. Not finding much with 235s on a ls3

black96ss

Really nobody has anything to say? If it makes 530ish on a ls2 wouldnt logic say it would make more on a ls3?

Got uid0

I would call LG

black96ss

Hes asking about this cam with tfs cathedral heads. Not cam only

Joe_G

This is my advice as well - I'm sure they tried the TF 235 and for sure the stock ls3 heads and they will provide great advice.

It's a no brainer to swap the 243 ls2 heads to trick flow 225's. But I can't recall seeing what the gains would be for ls3 to 235's, not that common of a swap.

LG would be the place to start for advice for that. They were very helpful with me when I had a question about swapping from 243's to AFR 205's with my G5x3. Great customer service long after my purchase of the cam.

jim2092

TF would also be a good source of info. Had 235's on an LS2 because of the friendlier valve angle for a monster cam and they worked well. Believe the 235's were designed for the bigger bore.

Amwellls1

I called LG first, they seemed to think a worked over stock casting would be better. Not convinced based on the results seen with the ls2/225 combos in the past

black96ss

Anyone who has done the tfs 225 g6x3 combo have to fly cut? All the research if have read people have have milled the heads to 61 cc, stock gm mls head gaskets and have been fine.

You would think this combo on a STOCK ls3 shortblock would work and put down a little power and tq.

Now a tfs 235 has larger intake valves so i can see running into ptv issues when it comes to milling the heads.

What i also dont seem to understand is that a 6.2 ls3, g6x3 cam only, stock ls3 heads/intake makes 480-500 but an ls2 tfs 225s, same cam, fast 102 makes 515 -530 yet ls3 heads are stated to be better????? Even with worked over ls3 heads and a fast 102 on the ls3 shortblock puts down 515ish

Point is i dont see how ls3 heads are better and why wouldnt the tfs combo perform better on the stock ls3 shortblock. You would think it pick up 10-15 rwhp and certainly more tq over the 215 -230 it makes on the ls2. 530 to 545 would be pretty nasty for a stock bottom end 6.2. I guess people dont seem to think its worth selling off the ls3 top end to go with tfs cathedrals.

Joe_G

Remember, the ls3 heads are a very good mod on an ls2 - they are basically ls7 heads without the factory porting and they flow a lot on a 376 CI engine. Stanger383's ls3 head ls2 motor ran 10.1's and pulled nasty wheelies.

My point is your ls3 heads are pretty darn good, and are a lot better than ls2 heads. Ls2 heads to TF 225 is about a 50 rwhp gain. I don't think you are going to see that on TF 235's vs ls3 heads. But since you already have them, swapping heads is a pretty easy job on our cars, do it and let's see how you do! Only going to cost you for a set of head gaskets and bolts, not much money.

Can you get dyno results before and after the swap?.

jashmore1234

Here is a real world example (I think)with Dyno results:

http://ls1tech.com/forums/generation...2-ltr-ls3.html

JayplaySS2

http://ls1tech.com/forums/generation...inally-c6.html

black96ss

Did you have to fly cut and what head gaskets did you use?

JayplaySS2

No fly cutting and GM LS2 gaskets. TFS has a better valve angle for more ptv clearance