Get one from a late model 5.0 Mustang, T-bird, Cougar, Lincoln Mark VII, and small block late 80's to early 90's ford trucks (F-Series, Bronco, and E-Series van). Avoid the 5.0 Grand Marquis and Crown Vic; they have the bulky two belt design. There will be plenty of sets to be found at a local pick and pull.
2005 Ford Mustang GT
1968 Mustang Hardtop
Mods do the '68: '71 Mustang disc brakes, KYB shocks, 620 coil springs, 2 1/2" dual exhaust with Dynomax Super Turbos and MAC long tube headers, C4 with shift kit and TCI high stall converter, 3.40 gears,and 302 with, P&P GT-40P heads, a Ford Motorsports A-312 cam, .040" overbore TRW forged pistions, Edlebrock 600 CFM carb, Weiand Stealth intake, and 1.6 roller rockers.