Get the '91 - '93 4.0 head as it flows the best - raised ports.
Yes it bolts on - with some minor mods - like epoxying closed some holes used during casting - that become exposed since the 258 is narrower than the 4.0 - no biggie.
Best intake would be an '87 - '88 AMC Eagle water cooled / heated Alloy Intake - use a Mr. Gasket 4bbl to 2bbl adapter - this is what the MOAB JEEP Race Engine builders use - AMC / Renault spent a pile of $$ on Design & flow.
258 head is a money pit - forget it.
