The Ultimate 304...
The ultimate AMC 304 is a 360.
The 304 and 360 share a number of common components, including motor mounts, engine mounts, and accessories.
The 360 heads have large 2.02" intake valves, 1.60" exhaust valves, 4 groove valve locks and 3/8" valve stems.
The 360 valve guides don't protrude into the valve bowl, and have huge intake and exhaust runners.
Edelbrock makes a matched cam/lifter/intake package for this family of engines.
Most of the hot rod catalogs offer piston & ring packages.
The 360 is everywhere because it was offered in the wagoneer.
The '74 to '78 304/360 have the same cast iron crank. No forged steel was available from the factory.
The '74 to '78 304/360 have cast iron connecting rods. No forged steel rods are available from the factory.
The '74 to '78 360 heads have thin castings, pedestal mounted rocker arms, and not much chance for easy rocker arm upgrades.
The 304 and 360 heads will NOT interchange! You will do engine damage!
A set of aftermarket rods will set you back about $800 to $1200. Forged steel rods are a must if you plan to rev the engine more than 3500 RPM, add a nitrous oxide system, or supercharge the engine.
The '74 to '78 304/360 block only came in a 2 bolt main cap version. Two bolt mains are only good to about 350 HP, and only if you use good studs.
The '74 to '78 cylinder case (block) seems to have a problem with shifted sand castings. Sonic checking indicates that the cylinder wall is nearly too thin to use at the base of the cylinder before boring. (12 checked before finding 1 good block for boring)
Any attempt to machine the large pad between the center two exhaust valve guides, (for say, push rod guide plates) will result in cracks to the water jacket below. The material is too thin to machine nearly anything off of.
Pedestal mounted rocker arms and 5/16" rocker bolts don't lend them selves well to upgrades.
The motorcraft distributor is alright for an ignition trigger, but the duraspark box has to go!
The motorcraft 2bbl. carb is an utter waste of time.