Exhaust manifolds: 78-401 vs 86-360

[arter]

Are they the same? interchangeable? totally different? Thinking about taking headers off 401 and have pair of 360 exhaust manifolds, to go to single system. Any thoughts on 2.5" vs 3"? Thanks.

[Bob Barry]

Driver's-side will be different, passenger-side will be the same.

2.5" usually is sufficient with a stock or slightly-modified engine.

Biggest argument against a 3" is the extra cost for little (if any) gain and clearance issues. Some will argue it kills low-end torque, but I won't.

[mdill]

On the 78 The outside bolt hole maybe bigger (??) the 86 used small (5/16 ?) outer
bolts some time in the mid 70's AMC used 3/8 for all the bolts, then moved to the
same as the 86 on the bolts.

Mike D.