The "300HP" 4.6/4.7 Jeep/AMC "Stroker" inline 6 cyl engine package.
AMC V8 engine - Wikipedia
AMC V8 engine - Wikipedia
AMC Performance Engine Parts | Hemmings
AMC V8 engine - Wikipedia
The "350HP" is the next step up the ladder to more performance out of your 4.0 based Jeep/AMC motor. This combo features a more aggressive cam profile to give that "Lopey/Rowdy" idle
AMC 360 – CJ ROMBOLD
Remanufactured Long Block AMC 258 4.2L Straight 6 1972-1988
402-Inch Solid-Roller AMC Small-Block Revs to 7,000 RPM and Makes Over 600 HP!
AMC Performance Engine Parts | Hemmings
AMC JEEP 401 C.I. V8 CRATE ENGINES
AMC-8
Dyno Tested: A 440ci AMC 390 Designed & Built for the Street
Summit Racing SUM-CSUMEPAMC002 Engine Power AMC 304 Engine Build Heads, Valvetrain, and EFI Parts Combos | Summit Racing