Chalky

I just picked up a set of AFR 205 cc heads milled to 61 cc chambers. Just wondering if any Z06 owners have bolted on these heads and what gains they experienced?

MYCoupe

If you're going to do heads do the cam as well. Even if it's a mild one it will be a nice improvement over stock. I would think that with the stock cam you'll see a 15-20 HP increase with the AFR's.

ArKay99

I agree with Chalky, however, A while ago I think VHP did a 66cc AFR head only and saw like 33rwhp or something. If you don't want to do the cam, maybe a good alternative would be to use 1.85 rockers and new pushrods. The only thing I would be concerned about with a 61cc chamber and stock cam would be excessive DCR. This could lead to ping, detonation, and knock retard. I would suggest you work out your DCR with your stock cam specs before you set your SCR too high.

Chalky

DCR looks like 8.63.

Anyone know if LS6 cam is retarded? For some reason, I have it in mind that the cam is retarded by 3 degrees.

If LS6 cam is straight up, I get dcr of around 8.8!

Good news is we have 93 octane and E10 fuel. If all else fails, I'll pull some timing.

mdhmi

I vaguely remember this topic coming up before. Aftermarket cams aren't for everyone. For someone wanting a simple bolton 35 hp or so the AFR's are a good option.

Chalky

Exactly. I have considered a cam for some time but was reluctant to trade 110% reliability of factory setup. I figured I could get a lift with the AFR's and a cam could still be installed later if I choose.

0C_Williams@RPM

Did this exact swap two years ago and saw ~22 RWHP gain...about the difference in CFM between the heads.

Your mileage may vary.

Charlie

Chalky

Charlie: Did you see gains across whole graph? Was it a 10.5:1 motor?

0C_Williams@RPM

Chalky,

Yes, the gains were completely across the board. And yes, the motor was a stock Z.

Charlie