The 4V Cleveland heads make very poor bottom end power, but with a light reciprocating assembly they will make scads of top end power, from 5,000 to 8,000 rpm on the dyno, never seen any Windsor head come close to them on power!!!!
Dart recently came out with a block that will take a Windsor crank, has the distributor location of a Cleveland, and is available with a 4.125" bore with either an 8.2", 9.2", or 9.5" deck height, just your standard 460ci small block.... Soon to be available with the dimensions I want in aluminum!!!!! When it's available in aluminum (probably early Spring) I'm going to get one and send my old Cleveland 2V heads off to be ported and flowed at Erik's. Gonna put the whole thing in a 2400 pound car and go chebbie hunting....... Should be the most fun an old Blue Oval fan like me could ever be allowed to have!!!!!!!!
PS, make up your own performance numbers, I pretty much know where it's going to be based on what those tired old cast iron heads did the last time they were off the shelf and on a car with considerably fewer cubes.....