How about some early 80's camaros,get a good 350,4 spd combo,lots of the rearends were posi if you find a z28.Or try an early 90's caddy,impala,buick they had they lt-1 in them.I had one in a 94 caddy and had 660,000km's on it when i sold it and still ran like a top.I've passed a few of them up in just the last year at the local wrecker.If you want to stay ford,maybe a crown vic ex-cop car.8.8 rears from the explorers are a dime a dozen and lots of them are limited slip.I got lucky and pulled the drivetrain from a 68 t-bird that was rusted completely out but still ran fine.Got a 390,c-6 combo plus the 9 inch rearend.Grabbed the driveshaft as well,it'll need to be shortened but at least i have it.Big old ford 4 doors from the 70's are good and still pop up regularly,460's,c-6 or c-4's.Might even find a 302 around still.I found 2 68 torinos last year one is a 302 c-4 car and one is a 289 c-4 car.Even a good old late 60's chrysler still pops up now and then,440's,383's,318's.