Plenty of good suggestions here and a consistent theme I have to agree with in-general is there are a few imposed 'handicaps' that will make it difficult to achieve your goals. Unless you have a stupid-big budget you're really doing things the hard way. I don't want to discourage using this unique body style but weight is a killer of the trans. and ET. I'd consider doing a turbocharger and a t400 which will make some limitations like flat hoods and exhaust system easier to overcome. Might even be able to use a stock-block with that combo.