Magnum head and exh manifold ID

Actually my understanding of them is that the 318 and 360 magnums use the same heads and manifolds. Check it out for your self here --->http://www.mopar.com/muscle/index.html You'll have to look in their catalog but you will see they offer the heads as
P5007140 *Cast Iron R/T Head — 1.92" Intake, 1 5/8" Exhaust (5.2L/5.9L Truck Magnum/Jeep® Engines) $443.00 Click here
P5007141 *Cast Iron R/T Head — 2.02" Intake, 1 5/8" Exhaust (5.2L/5.9L Truck Magnum/Jeep® Engines) $508.00 Click here
P5007145 *Magnum R/T Cast Iron Head Assembly -- 1.92" Int./1.625" Ex. (5.2L/5.9L Magnum/Jeep® Engines) $783.00 Click here
notice they are for either 5.2 or 5.9. Same same.