My engine puked and had to get a replacement. I have a short block from an 84 Van and I don't want to convert to carb. I was going to put my set of 89 EFI heads on the short block, but the guy at the machine shop said I am going to screw up the compression ratio and could burn up the motor.

I have been trying to research a little and came up with the fact that the 84 would have a larger cc dish than my 89 and the head chambers are about the same. I would be lowering the compression a little if I am correct.

My question is: Will lowering the cr of my engine this much screw up my speed density system or will it compensate? Is it okay to put the fullie heads on the 84 short block and run it? Everything is stock.