ive got a lean burn engine in mine. I’ve took the head off and put a rs turbo hemi head on. That’s been ported and polished. Sodium filled valves. I’ve put a piper 285c cam in running on twin 40s and a xr3i exhaust.
Was a bit shocked at the outcome as only made 104bhp was expecting a lot more. Not sure if it’s the head or not. Tempted to get the standard lean burn head ported and put that on and try it.