does any know what the difference between afr 165 heads and afr 185 heads are???? which would compliment more and add more horsepower???.....i'm planning on putting a cam with a .500 lift, 75mm throttle body, not to sure what else....
afr 185's usually wont fit the stock short block if you have a bigger than stock cam. you will most likely have to get new pistons or have larger valve reliefs cut.
The 165s have 1.90/1.60 intake and exhaust valves with 165cc ports.
The 185s have 2.02/1.60 intake and exhaust valves with 185cc ports.
Both can be had with stud or pedestal mount mount rockers with 58 or 61cc combustion chambers for stud mount, 60cc for pedestal mount. Because of their in-line valve design, piston to valve clearance issues arise when using the 185s on a stock engine, which is one of the biggest reasons I chose Twisted Wedge heads over the AFRs. I wanted the additional flow capability of a 2.02 intake valve, should I decide to port the heads and throw them on a larger displacement engine down the road. With the 165s, I'd be getting them machined for a larger intake valve, which is something I'd like to avoid. The initial cost was expensive enough, although the TFS heads are cheaper than the AFRs. I'm not trying to sway you in either direction, but I will mention that with the TFS heads, the ports are in "as cast" condition, whereas the AFR heads are CNC machined out of the box, and will have a much cleaner port.