Type 4 Engine build basics, Best approach on rebuild options Options

[TomL]

I am hoping to build a good, solid, higher performance Type 4 which will be used as a daily driver, touring car and perhaps an occasional AX. I have some questions.
1. Are all type 4 engine cases identical? If so, why are "GA" cases preferable?
2. What practical difference is there between a 78.4 stroke crank and an 80mm crank--since the 80mm seems to be more prevalent and a little less expensive?
3. Which is the most preferable bore--94mm, 96mm or 103/4mm?
4. Is there any practical difference between standard 2.0 sized crank journals and chevy sized?
5. Can 1.8 heads be "massaged" enough for decent performance?
6. Pure speculation--What kind of HP might I expect out of an engine with: 80mm stroke, 96mm bore, a moderate cam, re-worked 1.8 heads (8.5 or 9:1CR) and carbs?

Thanks for any answers you can give
TomL

[DNHunt]

Dave

My 78.4mm DPR crank with type 1 journals needs some clearancing. The webbing at the top of the case has to be clearanced. The case at the top needed to be thinned about a mm and the cam is a reduced base circle. I would have to look up the diameter. The clearance between the crank and cam is approximately 1.5 mm. at it's closest so, I suspect that could be narrowed a bit.

Interestingly, I had 2 cam failures with ceramic lifters (I'm the 1 and only and I want to be in Ripley's). The reason for that was that the ramp rates for that cam grind on a reduced base circle were excessive. We kept the same base circle, took out 0.016" of lift at the intake valve and 0.004" on the exhaust and added 4 degrees of duration. Lift is now just under 1/2". All is now well and I can't tell any difference for sure. I think I can feel the cam come in around 3000 where the other cam was more seemless but who knows. It works now and I'm happy.

At any rate there are limitations with added stroke.

Dave