Have just bought a 1980 Golden Hawk with a 258 and T-176 tranny. I want to go V-8. Looks like finding a 304 is slim...they won't take a 258 core. So...my next avenue is a 302 that will bolt up to my tranny....how sweet. Problem is I'm stuck with a 90k mile motor...anyone know the value of this 258. I had compression test on all cylinders...all 6 were 155...was told factory new was 160. I also want to sell the complete a/c....any value ideas here? I don't know for sure if I have to get another bell housing so engine may sell with it.
1985 CJ7 - total customization underway, Sublime green and Plum crazy purple, Ford 9", 258 w/ Holley 475
1985,93 CJ7,YJ - L98 TPI Vette motor, Atlas twin stick, Dana 60s front and rear, Arbs, 39.5 Swampers
Love my 360 and the 304's I've had didn't make me wish for a 302 in any way, especially when it came to buying parts for it. That said, a solid 258? I'd build that one, maybe think about a 4.7 stroker or something.
As is everything Jeep...what are you gonna use it for? 1st, the 304 bore/stroke vs the 302. So, the 304= 3.75 bore 3.44 stroke...302=4.00x3.00. Common knowlege says that the 304 will provide plenty of low end torque, and run outta steam at 4500 rpm depending on cam/intake etc. The 302 will have less torque, but plenty to move a CJ nicely. These things will also rev to the moon all day long, 6500 rpm(?).
Having said all this, I'm re, re-doing a 360, T-18, Comp Cams 292 Magnum(2500rmp-6500, HUGE, I know), Truck Avenger 770(jetted way down), and 4.10's on a glass CJ-7. I wanted a trail rider, mud puppy...and the boys, 7&11, wanted a street machine they could see out of and maybe win the stoplight drags! Compromises or disaster?
"Sometimes you can't see the forest through the bird in your hand-hutch".
BTW, I've owned my 79 CJ& since '84. All my buds had 304's in all kind of Cj/J10's and Commandos. The Commando got a NAPA rebuild, w/all the upgrades, that lasted 2 years before blowing oil. He finally just yanked a 304 out of an Gremlin/Concord station wagon(5 door?). It still runs like a scalded ape. Must been made on a wednesday.
Not to go off topic but are you sure you want a magnum 292? I have the comp mutha thumpa 287 and it is pretty much to big for my 401, and it's 30 over with 11.5:1 compression. In a 360 it would be even worse. You probably will have no power and bog and stumble till you get at least to 2600,2700. And 0 bottom end at all. I wouldnt go that big in a 360. But that just my opinion.
Levergun, I agree 100%. I have the same comp ratio (BullTear forged). But I got the cam/carb for free in a deal for a set of highly modded 1970 dog-leg heads w/roller rockers. Maybe this is why the stuff was so cheap! Supposedly the heads were spec'd to an AMC R&D program way back then. Maybe 33's will help me? I've got a reverse tilt nose, so when I see how impractical it is, changing it to something rational shouldn't be to awful hard Thanks for the heads up about your camshaft, might go 1 step below yours.
I built a 360 for my brothers 79 cj7 a while back and it was nothing to crazy. We put the comp 270 in and it pulls hard right off idle. Doesn't have the insane pull my 287 has but a lot smoother lower power. Offroad the 287 I have sucks. Especially with a 3spd. My leg gets tired really quick. If you want something more aggressive than a 270 I would look at a comp 276 or 280. They probably will pull really hard from 2400-5500 and still allow you to be able to idle. A 292 will struggle to idle in a 360.
My pistons are speed pro by federal mogul with forged rods. I have cobra roller rockers too and I really like them. Valves and springs are comp stainless.
On topic, I wouldn't trade my amc for a ford, ok, maybe a 427. And I would go 360 over the 304 as usually cheaper to acquire and there is no replacement for displacement!!! But all in all I think the amc v8's are some of the best out there.