[olddog]

I have a similar engine, with the same intake and EFI. While you have the engine apart, check the intake out closely. Some of my fuel enjector bungs were 1/4" into the air flow path. Most of the bungs were no longer round where the welds were at. It took very little work to clean that up. Also port match the intake to the heads.

If you need to machine the pistons for the valve clearance (and you will if you go near the .7" mark) it will change the ballance. If it were me I would get it re-ballanced.

My engine wants to idle about 500 rpm cold and comes up to 900 rpm warm. Does yours do the same thing? I'd like to know if it is typical, before I continue to dig into this.