They're pretty comparable. The AFRs are CNC ported and will slightly outperform out of box TFS cast 170s. The 170s have a ton of potential, though.
The ARP washers are wide enough to hold them down. The dowel holds the head in place, not the bolt. 10 years ago, no one even knew what step washers were. It's something someone invented for a problem that didn't exist to make money.
Kurt
You don't even need the step washers. Just bolt them on.
Kurt
Would you say the 165cc AFR's is a little more torque friendly
and the 170cc TFS is a little more top end friendly??
They're pretty comparable. The AFRs are CNC ported and will slightly outperform out of box TFS cast 170s. The 170s have a ton of potential, though.
Historically I would have disagreed, but AFR has raised their game with the revised heads. I still wouldn't buy 165s myself, but that's only because I'm crazy.
185's
No. Nic has TFS TW CNC ported 205s on his 302. He has some super impressive results with them too, but that's an expensive head, and the AFRs are not even cheap.
Anyway, if you're concerned about notching, consider the TFS heads with their "twisted wedge" approach, they can be run with most cams without PTV clearance issues.
To me, the milling question comes down to whether or not you want to shave the heads to gain some compression. If you don't mind running premium, don't have blower or turbo ambitions, and are trying to get the most out of your combo without finding another way to boost compression, then mill 'em. Just leave yourself a little room to flatten them again later before you sell them or reuse them.
Correctomundo... You can run the TW 170's with the 2.02/1.60 valves on a stock piston as long as the cam lift is under .540 If memory serves me right. BUT.. I would always check the PTV clearance regardless. Cheap insurance.
Just know if you mill the heads it may cause alignment issues with the intake holes and change the pushrod length. Plus it even more of a reason to check PTV clearance.
FWIW, peak lift has absolutely nothing to do with valve clearance. My setup has .570ish lift and I have plenty of clearance, on true flattop '86 pistons. It's all about where your valves are when the piston is hanging around TDC (exhaust closing/intake opening).
Isn't the 5.0 a non-interference motor? Maybe the rule of thumb is that .540" lift is what makes it an interference engine? Just curious...
Isn't the 5.0 a non-interference motor? Maybe the rule of thumb is that .540" lift is what makes it an interference engine? Just curious...
Well I wouldn't say it has nothing to do with it.
Kurt