Going to run 3.54 grears with a posi. From the factory, the AMC 390 was rated at 315 horsepower at 4,600 rpm with peak torque at 425 lb-ft at 3,200 rpm. I have 2 sets of heads 093, and 993. Also have a Performer intake, and a torker. I always thought the 70 390 and 71 - 401 ran in the 365 to 375 HP range, with the high compression, around 10 to 10.5 to 1 . I already have a built TH400 with a 3000rpm converter. I would replace the valve springs and prime the oil pump before firing it up because it has been sitting. The article also says that a comp 268H cam had almost the same specs at the 401/Police cam. The 71 401 was rated at 330 HP but running the specs though a desktop dyno type program you get more like 365 HP. Any body have some dyno proven 450bhp 401 builds out there? I do believe he has a HEI dist. FYI i have no idea on the build besides what he told me but here are his numbers. AMC 401 dyno numbers Got an email from a friend, stuck his fresh 401 onto a dyno. What cam, heads, and intake? Otherwise, the 290-401 is … AMC 401 … I have not personally run the motor but I pulled the pan and checked the bearings, motor looks very fresh. The idle is smooth he says 750 rpm very mild tone (lope) indicating a performance cam but nothing annoying for what that is worth. The AMC's greater length stems from its multi-tasking front cover, which contains the water, oil, and fuel pumps, and ignition distributor drive. https://www.hotrod.com/articles/ccrp-1301-780-american-horsepower Follow along as we complete the budget AMC 360 engine build for our 1967 AMC Rambler project car and dyno test several parts combinations for 480 horsepower - Car Craft Magazine For example, even with the modifications to more reduce emissions and increase efficiency, AMC's 401 cu in (6.6 L) engine was among the strongest factory-spec engines available in an American car in 1971, with more horsepower than Pontiac's standard 455 cu in (7.5 L) and Chevrolet's 454 cu in (7.4 L) that powered the Corvette. The dyno test was stop on to what a desktop dyno program I had predicted. The Police/401 cam was reported made by General Kinetics for AMC. Again, for the dyno tests the engine sported a 750 cfm Braswell carburetor drinking 110-octane fuel. I purchased it as a fresh motor with dyno time and 30 passes. 390 AMC Dyno Run 11:1, Edelbrock Heads Roller Solid Cam Edelbrock Intake, 750 Holley 530 HP - 530 FT-LBS The 401-SR heads are bolt-on high-performance replacements for factory iron heads and will accept AMC intake and exhaust manifolds and engine accessories, but Jeff chose Indy's 401-3 single-plane aluminum intake manifold, which was also ported by Coil. Timing was set at 34 degrees, and 2 … This is going to be a street motor so 9.5:1 comp is preferred. So that engine was underrated at the factory.