Fear
I was flipping through some Jeep books and some seemed to dog the 304 saying they had horrible power. I have a hard time seeing how a 5.0 liter V8 from anyone isn't build-able for all the torque a Jeep could need. What's realistic dyno numbers on a moderate 304? Something along the lines of a 4bl, Edelbrock dual plane, headers, elect dist, 9:1 comp and a cam around 268 adv dur. I wasn't planning on snagging a 401 because I thought it might be overkill and run too hot on the trail, but if a 304 can't put out 300+ torque, then I need to adjust my plans.
I already have the 304 in my Jeep. I like the idea of keeping it an AMC engine, even if I swap out the factory 304 for a 401. I've played with Chevy small blocks for years, I'd rather play with something different like an AMC.
jeepsr4ever
320hp+ There is nothing wrong with a 304. You can arguably make more hp with a 304 than with a 302 ford from the same years with factory heads.
tufcj
I had a 304 in my CJ for lots of years. Had 10:1 compression (forged pistons), heads polished and ported with 1.94 and 1.50 valves, a cam with .488 lift and 280 duration. Rods were shot peened and the rotating assembly balanced. Ran a torker manifold with a Holley 600. Revved it all the time to 6500+. Dynoed at 310 when we first built it, probably made around 330-340 once we dialed in the timing and carb. Guys on the mud bog circuit used to ask to see the engine all the time because they thought I was running a SBC.
Nothing wrong with a 304, it's just that there's no replacement for displacement. 360s are just as plentiful, if not more, and cost to build is about the same. Why not have the 56 extra inches?
Bob
tufcj
Fear
How hot does all that cam and compression run on a slow moving trail in 90's weather? All my hotrods have been on the street where you get lots of airflow. Most vehicles I've played with on the trail had bone-stock engines. I'm picturing a balls-out drag engine running hot as hell, pinging and having crap for bottom-end torque on a trail rig. A 280 cam is what I start considering a pretty hot cam for a street engine.
tufcj
I ran mine with a flowcooler water pump, a 7 blade clutched fan from a Wagoneer, a good 3 core radiator and shroud. Never had any problems with overheating on the street or on the trail. The shroud is very important for airflow at low speed.
Bob
tufcj
newt
For low rpm air flow - I've found that a huge belt driven fixed fan works better than anything fancy out there. I like the Flex-a-lite 5700 series in the biggest size you can fit - no clutch. I run the 19" on my CJ w/401 and move enough air to suck yippie dogs through the radiator. It cools much better than anything else I tried. I'm sure it costs me some hp, but I never overheat anymore.
