Trex with 243's??
 

Alright so I have a collection of parts that are itching to go on my car, one of them being the short armed dinosaur(cam). A buddy of mine offered me a good deal on some 243 ls6 heads and brought it up to a friend of mine and told me that they might not work together because of different valve sizes. To my knowledge they have same size valves but smaller combustion chambers compared to 241 heads.

So does anybody if they would work together or not?

Also if I do get the heads, of course I'll be replacing lifters and using mls head gaskets and I already have 7.4 pushrods, will I have any issues with these pushrods? I heard for this cam you need stock size pr's but thunder racing package sells them with 7.4's?

The valves are the same size, but the chambers are 2cc smaller on the 243 heads.

It will be really tight.

Do you think it will be fine? I dont want to my motor to be a ticking time bomb lll

Always measure no matter what scenario! If me i would go ahead and flycut anyway just so i could mill the 243's to bump the compression. AI can cnc the heads to make the cam fit withput flycut i would check out his 500$ head work to get a cnc valve job and deck resurfacing and make fit your cam.

Well that sounds like a good idea but its not in the budget really since my t56 took a shit on wesnesday lol. If there actually is issues with the setup i may just do the cam swap and save the heads for my second gen if i decide to keep it or get them worked on later.

You can eek by with a Trex on stock 241 heads, but I wouldn't chance it with the difference in between the two.

I could spec you a custom grind that would work and be just as nasty if you like?

This...go this route. Then you will be worry free. Martin knows his stuff!

Thanks buddy!

I try! I will start to post up results on the dyno from the custom cams I spec.

I will be bringing that aspect of our posting back since we haven't been really showing off our new in house tuning that we're doing now since moving locations.

My buddy had his 243's decked 0.036" and he had to fly-cut IIRC almost 0.090" with his T-Rex setup.

with a big cam like that also consider some trunnion bearing upgrades.valve train geometry is very crucial with high rpm cams.and look at a little thicker head gasket to maybe gain some extra clearance.get some good valve springs.Damian specs a cam that makes great power .

Stock 243s unmilled with stock gaskets have same valve drop as 241s/stock gasket.
In any case TREX should have PTV measured.

Bad idea increasing quench. This will make setup more prone to KR

I was wanting to do this cam at some point also... So is it a no go with 243's? cause I was planning on getting either the 2.5 ls6's from tsp or some prc 2.5 5.3's

i have 243 and a trex...40,000 miles and still goin......243 and cam installed by tick

oh and i have .024 ptv clearance....no flycutting

So the higher CR from the smaller chamber has no effect on PTV is what you're saying?

Correct, smaller chamber is not from milling but from design. Valve drop are the same. Valve drop is the distance the valve travels when it free drops and contact piston (from full seated position to piston at TDC without spring). This is on same motor. On different motors it could be different if piston to deck height is different.

Those are some nice numbers on your sig. Im hoping for something in that range, plus i have nitrous for it as well. :D

I will go ahead and do the cam swap first that way i can get rid of that ls6 intake and get the heads. After i gather everything for the head swap ill give it a shot

Thanks for the education lesson Pred!

Even I don't know everything contrary to belief!!!

youll always need to measure. its going to be very tight. some people have no problem, and some people have ptv problems with stock heads and a t-rex. If it is too tight, you can always flycut a little