It would be very tight and would definitely have to have custom headers. The early A bodies have extremely tight engine compartments. The 273 and LA engines are tough enough. The 5.7 is a very wide engine with coil packs and accessories. Certainly would be quite a ride with the 5.7 Hemi. The A-body did not officially receive the B or RB engines until the 1967 Model year. They are wider than the early A-body. A 65 Barracuda would require some creativity to get the 383 to fit, but certainly could be done.

Back to the money....buy high-sell low. Always works on Hot Rods.