AMC 401 - Forged crank & connecting rods???

[CJ-7-401]

On a Jeep unlimited forum thread there seems to be a dispute on whether a STOCK AMC 401 from the factory has FORGED connecting rods and crankshaft??

Most say "Yes" , but some can support no.

What is the correct answer here.

This website forum is my most respected on this subject.

Thanks,

Jim

[AMX69PHATTY]

:idea:
All stock Cranks and Rods are forged in both 390's & 401's per "Performance American Style".
:wink:

All other rods 5.875 290-304-343-360 are malleable iron and
cranks 290-343 @ 3.28 & 304-360 @ 3.44 are cast iron.

[jeepsr4ever]

Yes forged crank and rods!

[82Waggy]

All 390's, 401's, and the illusive so called 360 service block also have thicker main webs than the others.

[JERSEYJOE]

I have only seen one of these rare 360 Trans Am blocks in my lifetime. It was installed in a 73 Javelin and I was replacing the rear main seal. I almost freaked when I saw it. The owner had no idea where it came from. This block had no cast in marking to indicate it was a 360. Not sure if all the Trans Am 360 blocks were like this. The bottom end had the same webbing as the 401, not sure if the cylinder area was thicker, but I imagine it could accept a larger over bore than .040.