AMC motors have always been stuck in an alternate universe by virtue of their physical stature. The 290 V-8 is externally the same size as the 390 and a full 100 ci smaller. Even the 401 shares the same external dimensions; so are they small-blocks or big-blocks? To confuse matters even more, Indy Cylinder Head, makers of all things Mopar, just released a new AMC block carved out of aluminum, able to support a whole lot of cubes.

We followed along as Indy and Payton's Performance screwed together the ultimate bracket bomber 500-inch (yes, we said 500-inch) AMC V-8 for Mr. J.T. Payton, an AMC junkie from way back when. So what is it, a small-block or a big-block? We can tell you that with a pair of Indy's own aluminum AMC cylinder heads, this engine made big-block power at big-block rpm levels-840 horses to be exact, at only 7,200 rpm (right now you big-block guys are screaming foul, but in racing terms, this is low-rpm). If that wasn't enough, the engine weighs a light-by-small-block-standards 450 pounds completely dressed out! Chevy's own rat motor tips the scales at a portly 700 pounds. Show us a big-block that can make that claim!

Indy Cylinder Head, gurus of the big-inch Mopar, and Payton's Performance, gurus of American Motors products, put together an all-new AMC V-8. So is it a big-block or a small-block? You be the judge. Just remember, whatever it is, it's 100-percent bad-to-the-bone.

Who Is J.T. Payton?
J.T. Payton is an AMC nut stretching back to 1972. When he was young and on a limited budget (read: broke), he had to go the most economical route. through trial and error, he found that AMC engines were easy to keep together, as well as cheap to build. The high-nickel blocks of the 390s and 401s are tough and easy to weld if need be. Factory dog-leg cylinder heads flow better out of the box than most competitors, and if one used a closed-chamber 401 head on an earlier 343, and fly-cut the pistons for piston-to-valve clearance, they would have a low-dollar 12:1 engine. Because aftermarket parts were in limited production, the AMC rodder would have to make the factory pieces work. AMC spawned innovation.

J.T. is the proprietor of Paytons Performance, the one-stop Rambler shop known as the Mecca of AMC performance circles. J.T. also races a Gremlin. So far, with only limited tuning under its belt, he's managed a very promising 8.55 at 156 mph-in a Gremlin nonetheless! J.T.'s good buddy Bill Tichenor-marketing manager at Holley Performance Products and instigator of this engine buildup-also discovered at an early age the advantages of the AMC. As a high school student wanting a musclecar and on a high school student's budget, he found the path to American Motors, as they tended to be more affordable than more mainstream musclecars. Bill found a '69 AMX for chump-change and drove it daily.