I recently bought a set of tfs 205 heads used for my car. I sent them to the local machine shop just to make sure they were straight and there weren't any probs. they ended up having to deck the heads a bit and now they're 57cc chambers. Stock at 58cc chambers with .041 they would've worked without fly cutting but I'm afraid it won't work without fly cutting now. Cam is a 237/240 622/588 112+3. Anyone know if these will work or not?

 

they most likely decked them .005-.006 . to only reduce the chamber by 1 cc.if the pistons need fly cutting now ,they would have needed them before they were decked .use a thicker gasket ,or a different cam .they are good heads .make sure the valve seats don't leak .

 

I freshened them up while they were there. Thought so, I may just use a bit thicker gasket then.

 

You should probably check your ptv. It may even be possible that the extra.010" isn't enough. Better safe. I'd probably rather flycut and run proper quench. Even on my motor that will be boosted I'll be between .035" and .041" for quench. Sure it doesn't matter much at peak power(boosted) but low RPM it helps a ton with turbulance.

 

You should be fine... they have more than stock PtV clearance at 58cc... remember, they are cast that way. They weren't milled to get that chamber size.

Still good to measure, but I would not run a thicker gasket. You're gaining .013" of clearance... and as Gary said, if you have to flycut now, you had to flycut before.

 

search for threads on fly cutting .some one on here rents out the tool you would need .I would not recommend NOS on cut pistons .

 

Not going to fly cut, if they won't work I'm not going to use the heads. I plan on spraying later on so fly cutting isn't an option.

 

Perhaps you should just get rid of your phobia. It is ok to flycut and spray, just make sure the cuts are de-burred. Why does a lot of people like to push envelopes unnecessarily. Do it right, measure, and if margins seem unsafe flycut/mill some more to achieve proper tolerances and desired compression for fuel used.

 

It's no phobia, at 58cc with a .056 gasket my brothers car was perfectly fine with a 234/242 cam, but I'm just making sure.

 

Always measure, just because the motor runs it doesn't mean it is safe.