Most of the time clearances would be fine, but since you are having the work done get it the way you want it, I had issues this year running too tight of clearances I believe, so I loosened them up and ran a better bearing, i am running .003 on mains 1-4 and .0035 on rear with HV oil pumps, spring shimmed .095 to get a little more pressure, I get 75 psi cold and after a good run 40-50 at idle. I also spent the extra for coated bearings, just to make sure I covered it all!

With the oval port heads, you can run a little more duration on the cam and still have a good idle and good torque. I would run a cam like the Merc 525 cam. Or just run the Crane 741 cam. It would be a good match to your engine.

does the "741" cam slide in the gen IV ? i was under the impression it was for V or VI

741 is the grind/ profile number.

When you order the cam you tell them flat nose, early generation IV, or step nose, late generation VorVI.

Yeah to what he said!

Hey Enforcer...before you make a final decision on your engine you should call Ateco. They do long blocks and short blocks plus exchange engines. My buddy got an exchange engine this summer and is very happy with the results. Ateco did my engines 4 years ago and I've had no problems. They're real well known here in the Great Lakes area, so they must have a good reputation. Can't hurt to check them out first. Bill's a good guy to talk to whatever you decide.