2RZ tech info - single cam, twin cam, efi, and carb differences

[Shifty]

Hey kids

I've decided that with all the piss-farting around involved in converting Toyota V6 engines to RWD, it just makes sense to be boring and stick with something that was supposed to be there.

I've done a fair bit of searching and the earliest 2RZ (exact name unknown?) was in around 1989 and ran 8.8:1 for 113hp / 196nm (out of interest, almost identical to a 22RE) compared to a much later model figure I found of 9.5:1 and 143hp and 217nm... vastly different result!

So, are the earliest 2RZs carburetted? And single cam?

And, say I fit one of these, are they outline interchangeable with a 3rz block at a later stage?

[Shifty]

ok well so far i've confirmed that they were single cam and carburetted in the earliest models.

any more knowledge on the topic and / or interchangeability?