440 tunnel ram

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!
The simple answee to whi make desent stuff in uk is noone we import 90% parts from US as uk suppliers import an way.

With 660s can you get diffrent size centre squirters or is it just jet sizes you can change