Yeah,I would agree w/ John on hds over 700 lift,on the other side of the coin how much money do you want to spend.Even the 205s are`nt cheap and I don`t think I`d run them on the street,you would never use their full potential.
With most any of the aftermarket heads, you risk fly cutting pistons. It's not so much the lift of the camshaft, but the profile. Where the max lift is at 30 deg BTDC, 0, and say, 15 deg ATDC. The exhaust valve usually isn't a problem. One, they're normally 1.60 or 1.65 diameter, which most pistons are already made for. Two, they're usually almost closed by time the piston starts chasing the valve on the way up, unless you're like me and have a camshaft profile that doesn't really fit the engine (I had to cut them....quite a bit). The intake valve on the other hand, tends to chase the piston while the piston is going down the hole. Lots of things come into play here. The relief in the top of the piston. If it's made for a 2.02 valve, a 2.05 or 2.08 ain't gonna work. If the cam profile is pretty aggressive, it's not gonna work (i.e.-opening the intake valve faster than the piston is moving away from TDC...and this is where rod length and stroke come in). Among other things. Call speed-pro and ask them what the relief sizes are in your pistons, if you know the part number. Chances are you'll be ok with the Victor Jr's, but the AFR with the 2.08 (IIRC...too lazy to look it up) valves may be an issue. Being hyperutectic, there's a chance that they were designed around a typical "street" engine's 2.02 maximum. Most of the forged pistons, although more expensive initially, will accomodate a 2.05 easily, and many times a 2.08. I cut mine in the block. Ended up taking it all apart anyway to clean out the metal. Ain't worth it, IMO. Aluminum shavings are REALLY lightweight, so it gets in between the piston and the cylinder wall easily. Some guys said use grease around the edges, but I found that all it does is collect more shavings and make it harder to clean it up. I used a spare valve (intake and exhaust) with a piece of 40 grit sandpaper glued to it, spun in a drill motor, to make clearance that I needed. It worked. Took forever and I ended up taking it back apart anyway. Will not do again. Easier to pay someone to flycut them, and probably more accurate too. But keep in mind, mine is oddball (well it was when I built it). 4.125" bore, AFR225 heads, cam is aggressive (284 duration at .050), and almost 16:1 compression (currently backyard modified to get it down to 15.3).
Mavman hit the nail on the head. With the old Maverick motor we had 270@.050 intake and 284@.050 exhaust and around 15:6CR(the motor was originally setup to run Alcohol). After the rebuild we took some material off the huge domes and are now at 13:6 to 1CR(to run 112VP gas) and also changed the profile to 278@.050 intake and 280@.050 exhaust, but I'm running very old TF-R heads. I have fly cut pistons on the bench and in the motor and doing it on the bench is much preferred to doing it in the block...............IMHO
