86 brougham ECU RE-TUNE/re vamp

I apologise in asking, what to you guys, must seem such a basic question .
What should I get rid of on the puter, what should stay ?
The 'rough' changes to the vehicle are as below
Remove the existing 307 olds and replace it with a 66 toro 425 10.5:1 .
The replacement carb is non ccc .
The intake mani. is an O4B .
The heads are currently being ported and polished . These will take a set of headers( custom no doubt !!) .
The cam won`t be wild (hyd. lifters and stock rockers staying)
The trans was to have been a th400 but am now going with a strengthened 200 4r .
The final drive ratios will be 3.08 to 3.23(NODIH has kindly given me the low down on the options here.)

That said , I am after someone in the not-too-distant future to see to the impending alterations .Sure, I am a long way from the states but happy to pay the extra postage .
regards mike