1985 amc 258 High-Performance Engine Build

Hello All!

I have a 7120 4.0l head, Holley 390cfm with Clifford Intake, and long tubes on hand. 

I want to increase the compression ration by installing flat top pistons. I was looking for 199 pistons, but I couldn't find a supplier for any. If I cant find a supplier, I might send it off to the machine shop to get decked and bored .060 over. Any performance oversides pistons I can put in?

I want to put in an aggressive choppy cam that gives me a fun street-able jeep. This Jeep will be mostly seeing just the street. I was thinking a duration of 218/226 at .50' lift with stiffer valve springs and a new timing set. 

Are there any other performance mods I can do to squeeze as much fun power out of this thing as I can? 

Lots, they're pretty much only limited by the depth of your wallet. There's an aluminum 4.0 head out there, which would shave weight and help it deal with the higher compression ratio. It's spendy. There's plenty more head work that can be done to liven up that 4.0 head even more- port work, larger valves.

HEI dizzy would also be a good idea for the higher compression. They're pretty reasonable in cost.

Of course you could really go nuts and go with a turbo.

While you'll never see huge power numbers with a 258, from the factory they were rated at around 110 hp, I don't think it's unreasonable to expect 200 out of a proper build. Bigger numbers can be had, again, all depends on how much youre willing to pay. Still, 200hp should be a heck of an upgrade over the wheeze stock engine.

The stroker website referenced is great. Plenty of other info out there- do some homework and you'll come up with lots of ideas.