Definitely try the 660s on that, vacuum secondarys have no place on that!!
Cant help with the rest as i dont know who makes good stuff in the UK for converter.
Throw a high stall quality converter, good heads and away you go!
I think the 660s are way more suited to a high performance build/race car. I have a set for my new build and they dont seem to friendly for street use. They are all 8 at once. Im currently running twin 4160 450CFM non vacuum on my high compression 360. (Non progressive)
The 660s are for my 6-71...