Gen2 crank in gen1

[Professor]

The rods are the same length from Gen I to Gen II. The difference is from the smaller wrist pin and the pin location is moved higher by about 1mm. So I also wondered about the .040 being sufficient especially if the head has been milled or angle milled. I personally don't think the rod angles are that bad to cause the problems you have seen but could be wrong.

Because of the smaller wrist pin I heard some have had issues with reliability in that area.

I have the APE 1441 kit from APE for the Gen I but not yet installed. I wonder if I should exchange the CP pistons for Gen 2 CP pistons with steel wrist pins and run Gen 2 Carrillo rods.

Nothing wrong with a spacer. I'd suggest checking the deck height and select a gasket/shim combo to get your desired results.

I used two OEM gaskets and a shim/spacer from Cometic. They will build a spacers in the following thicknesses. .010”, .016”, .020”, .025”, .032”, .040”, .050”, .063”, .080”, .100”, 125”, .188”, .250”, .313”, .375”, .500”. I bought OEM and Cometic base gaskets and a couple of shims so I could mock it and measure it. I think the .040 would work fine as I know APE sells a ton of kits that way, but I really wanted to use gaskets on both sides. Mine is set a bit tighter than the default combo.