I recently picked up a set of NIB TEA tfs220's from a buddy that came from TEA with their valve job and BTR .660 springs. These will be replacing a set of ls6 243's that were cleaned up by a local shop. I believe I am going to use morel 5315 lifters and 11/32 pushrods from BTR. Plan on sticking with my current cam if it stills looks good 235/242 .621/.592 on a 111+3. I have thought about going with a llsr set up but I'm not sure I want to drop the coin or the time to set it up on a sbe ls6 at the moment. One question I have is, is it worth having these heads milled from the stock 64cc to 61cc? That would bump me up to 11:1 from 10.5:1 with the stock mls head gasket. My current set up has gotten me a 10.93 at 124 for what it's worth.

 

Absolutely mill the heads

 

I'm sure you can, but would you mind telling me the advantage of milling the heads? I'm guessing maybe 8 peak hp?

 

Short answer, that cam will be very lazy if you do not bump compression. Compression helps restore performance on the low end that is lost to larger cams. As well as carrying past peak.

I have never done a back to back identical build with milled and unmilled heads. But I have done mild cam stock compression builds and moderate cam stock compression builds and moderate cam increased compression builds and large cam increased compression builds. Given how those went I would not go above 227 duration on stock compression.

 

What heads on the car now?

 

That cam would prolly like a .020” mill and thinner cometic head gaskets
11.3-11.4 should be the target squeeze

 

Thanks for the info darth! I knew it was worth some, just didn't know how much

 

I don't think I can get there with out flycutting.

 

243's...

 

You will be close on PTV given the increase in intake valve size. Keep in mind you will gain some clearance with the 13.5 degree valve angle.

Are these ls1 or ls2 version of the 220? The ls1 has 2.04" intake and the ls2 has 2.055" intake.

They will be marked on the front corner of the head right above the exhaust port.

I would mill to achieve 60cc chambers and keep the quench tight. If that means reducing from the stage 4 to the stage 3 it will be worth it. Compression makes power!

 

They are the ls1 heads. I've been told that I can mill them to 61cc with my current cam and be ok on PTV clearance. Not really excited about pulling the cam and going with a smaller one. If I did I would probably just go LLSR. I am hoping it picks up pretty well with the new heads. At the least, the thicker deck and added clamping force with the studs will hold up to the nitrous better than the stock castings.

 

Those heads, the valve job, and bumped compression is gonna make a big difference. You gonna look like this for a while

The benefit of milling isn't just the hp. If you've never bumped the compression or timing on a vehicle that was lazy and felt the difference it's great. Lower compression makes for a lazy dog feeling motor, even if it makes big power it'll feel a dog. Bump the compression and it'll be snappy and really responsive, and a LOT more fun to drive. It increases everything everywhere. Larger cams lower your dynamic compression ratio so it's especially important with cams like you have to raise the static compression to get back what you lost and make the most of that cam.

 

Thanks for the reply pooter! I'm excited to get the heads done and get the car tuned. I'm sure it will make **** numbers on a dyno with the stalled th400. But it should pick up nicely where it matters, the track 😎

 

Let us know how it works out!

 

What did u guys think is the max cr to go on solid LS6 block with the add of some spray and a hci swap?

 

Do what?