AMC punched over?

[jshankcj7]

Hello, I just learned that my motor is in need of boring with out of round cylinders. I have a 74 304 and it will cost me $20 a hole no matter how much I go over. I was wondering how far I can go over and what it would involve me buying new to accomodate the larger bore? Thanks guys, you never let me down. J.Shank

[tufcj]

Boring by itself really does very little for power. Each .030" overbore adds about 5" to the displacement. Power is made by the compression, cam, intake and exhaust. That's where you want to spend your money.

Personally I would go with the smallest overbore that would clean up the cylinders that has readily available pistons. 304s weren't popular, so piston choice is limited. All you really need to buy is new pistons and rings, you can re-use everything else if it's serviceable, but I'd drop in a new cam/lifters/timing set as long as I was in there.

Years ago, I built a 10.5:1 304, had the heads ported/polished with 1.94/1.50 valves and a big cam, and the whole thing balanced. I regularly revved it to 6000-6500 when mud bogging. Everyone thought it was a SBC conversion until I raised the hood.

That said, today I wouldn't build anything less than a 360. Cost is pretty much the same, but performance is better, and it bolts in. Core engines are cheap/available in Wagoneers up to 1991, and more parts are available.

Bob
tufcj

[amcjeepman]

Boring by itself really does very little for power. Each .030" overbore adds about 5" to the displacement. Power is made by the compression, cam, intake and exhaust. That's where you want to spend your money.

Personally I would go with the smallest overbore that would clean up the cylinders that has readily available pistons. 304s weren't popular, so piston choice is limited. All you really need to buy is new pistons and rings, you can re-use everything else if it's serviceable, but I'd drop in a new cam/lifters/timing set as long as I was in there.

Years ago, I built a 10.5:1 304, had the heads ported/polished with 1.94/1.50 valves and a big cam, and the whole thing balanced. I regularly revved it to 6000-6500 when mud bogging. Everyone thought it was a SBC conversion until I raised the hood.

That said, today I wouldn't build anything less than a 360. Cost is pretty much the same, but performance is better, and it bolts in. Core engines are cheap/available in Wagoneers up to 1991, and more parts are available.

Bob
tufcj
X2