3.5 Carb to EFI

Hi all, I'm still on my quest to have my 90 3.5 (carb) work correctly with the autogearbox fitted.

I understand that my 3.5 is low pressure and the EFI version is high - will just changing the heads from the EFI onto my engine fully convert the beast to EFI spec?

I'm pretty sure that with this littlebit extra power my gearbox will work more smoothly - if I can avoid changing the engine I will, as apart from slightly low power it runs fine.

I've got a feeling that it's the pistons that define the CR, but stand to be corrected on that.

When we got our short engine the pistons were all marked '4.0 H' which I took to mean high compression, but could have been a weight/balancing marking

Easier to have different pistons than different heads probably.

Peter