I will be acquiring a sweet '02 Trans AM WS6 M6 this Saturday. It's a beauty with only 22K miles, never seen rain or snow. It has Kooks headers and a Borla catback. Other than that, the engine is stock. I'm considering a BTR Stage 3 cam and 243 heads.

What other cam might you recommend?

I would like around 11:1 compression. What would I need to mill 243s to get me there? I took .035" off the set on my LQ4 in my truck to get me there. I don't know what's required on the LS1. What about valve clearance? Would a BTR Stage IV be too big without fly cutting?

BTW, this will just be a "toy" car only driven on nice days. It might see the strip a time or two, but will not be heavily raced.

 

After some reading, it appears that any milling at all would likely make PTV clearance an iffy situation with the Stage 4 cam. Unmilled, the 243 heads give 10.5:1. I would love to achieve 11:1. Is fly cutting the only way to achieve this?

 

I used Mahle mls gaskets on my LS1 Camaro just recently when I installed a set of 799 heads. That puts me at 10.69 to 1 compression running only 91 here in So Cal. still it runs very strong in this cool weather.

 

Looks like it requires milling .030" from 243 heads to get 11:1 compression. That results in about a 60.5 cc chamber.

This won't give me the PTV clearance I would need to run a BTR Stage 4.

I'm now wondering if I should go with either Trick Flow or TSP As Cast 220 heads. I've yet to discover if those will give me the PTV clearance I need.

 

Get your combustion chamber down to 63cc and that will give you 10.98 to 1 compression.

https://butlerperformance.com/n-1287...alculator.html

 

If I said -leave it stock - would you reach across the Internet and choke me?

Car sounds too nice to mess up

 

Yes! I won't "ruin" this car.

 

IIRC, stock 243s have a CC of 64.5 cc and give a compression of 10.5:1. 60.5 cc takes it up to :1. I don't think 63 cc would give me 10.98, at least not with .060" MLS gaskets.

Anyone have PTV clearance data on the As Cast TF 220 heads?

 

The stock MLS gasket is 0.051, I don't know why you would want to use a thicker than stock gasket, a tighter quench is better. With a stock MLS gasket, a 62cc combustion chamber would get you to 11.04:1.
I personally plan on using a 0.040 gasket with 62cc chambers when I put my PRC 225s on, which would be 11.36:1

These are the numbers I used to compute compression:
Bore: 3.898 in.
Stroke: 3.622 in.
cylinder head volume: 62cc
effective dome volume: 0cc (flat top pistons)
Deck Clearnace: -0.007 in. (pistons poke out of the hole 0.007 in)
compressed gasket thickness: 0.051 in.
In reality it would be slightly less than the calculated 11.04:1 because of the area between the top of the piston and the top of the compression ring, I don't know how much though.

 

I guess I misread in my research. I thought the stock MLS gasket was .060".

 

For a street car I'd suggest a BTR stage 2, TSP 228/232 or a Cam Motion Titan 4. All similar specs.

 

The "Eagle" has landed. 21,800 original miles and in almost new condition.

 

Un. Be. Leivable.
That’s crazy nice!

 

Sweet ride! Good luck with the build.

 

No. Just do an oil and filter change. If worried about any sludge or crud, run a quart of ATF in it for a few hundred miles before the change.

 

Now I am going to find a dead guy so I can fill out his ballot to make another vote for leaving it stock.

That is a NICE TA!!!

 

Go to a smaller cam or custom grind, the stage 4 is way overkill for a stock cube LS1/6

 

I'm going Stage III.

 

Nice car. BTR stage 3 is still a lot of cam, I’d suggest something more like the stage 2 or Cam Motion Titan IV or similar which will drive nicer. Also check out the FTI Streetsweeper HT. I did 436/415 with that cam, stock 243s, stock LS6 manifold and .040” head gaskets. 350rwtq at just 2,200 rpm or so. Real nice useable powerband and good sound.

If it were me I’d use Cometic .040” gaskets to get your quench to a more optimal state. This alone should boost compression from 10:5 to 10.85 or 10.9 or thereabouts IIRC. Then just a light milling to the 243s and you are at 11:1.

 

I could live with the Streetsweeper HT. The others don't have enough overlap for the sound I want.

CM Titan IV 227/232 113 - 3.5° overlap
BTR Stg II 227/234 113 - 4.5°
Streetsweeper HT 228/232 111 - 8°
BTR Stg III 231/242 112 - 12.5°

I know, I know...don't pick your cam by its sound. It's a build requirement though. If compromises must be made, so be it, lol.