[16grem72]

I started working on my 401 and want a little more power out of it. so i searched for a Cam, roller rockers, lifters, headers and a intake. While i was searching for parts i had trouble locating parts for a 1978 jeep 401 (from a cherokee chieftan - its going into a gremlin.). A lot of things stopped in 1976.
Summit had the roller rockers, but only went from 1971- 1976 and so did the cam. Does this mean they dont work together and jeep changed engine components or is it just a misunderstanding somewhere along the way?

Also what would a good cam duration and lift be for some strip/street action? i dont want a real high rpm engine. i was looking at maybe a 234/224 duration from summit.

[Woody Williams]

You might want to try Maddog racing in Ft. Lauderdale Florida 800-792-9984 www.fastengineparts.com. They seem to have a lot of AMC high performance parts.

[farna]

All 401 parts interchange, as well as all 360 parts. The heads are IDENTICAL. The big difference between a 401 and 360 is the block, crank, rods, and pistons. Externally the 401 is the same as the 360. Internally there is a longer stroke made by using a different crank and rods (forged from the factory in the 401), thicker main bearing webs between cylinders, cylinders notched near the bottom to clear the swing of the crank, and of course the bigger bore. You CAN NOT bore a 360 out to 401 size -- the internal casting cores are different. You CAN use a 401 crank and rods in a 360, but will have to have the bottoms of the bores clearance notched, and my need custom pistons (I forget if pin height is the same on the two).

Early AMC GEN-3 V-8s (304/360/401, 70 only 390) use small combustion chamber heads for higher compression. These were dropped after December 1971 and a larger chamber head used. Contrary to popular misconception, the small chamber heads ARE NOT "better" than big chamber. Just buy the right pistons for the desired compression when building. Chamber size is the ONLY difference. Well, later heads have an exhaust crossover for EGR, but that can be easily blocked. The small chamber head casting number starts with "319". Only 401s built in 1970 for 1971 models (early 1971 models) will have them.

Some parts books stop with 1976 because that's the last year the 401 was used in AMC passenger cars. Jeep Wagoneers and Cherokees continued using them through 1978.