Head conversion advice?

[PEPI]

Hi forum members,

I'm getting ready to replace my engine.
I wish to get a new engine same as present - but deleting the standard cam less intake system, and replace with cams all round.

I've already have a very sound build plan for all else,just weighing up the cost side and not wanting to over spend unnecessarily.

Basically question is, is it cheaper to use my present engine and convert the heads.
Or is cheaper to get a vq35 and stroke to 3.7/3.8 litres.

I will be building a stronger engine internally etc - may look at FI later down the track couple of years.

Thanks in advance.