Head Replacement MFI 1981 CJ8

Hey all - I'm new, but I finally got a CJ8. Low mileage, ½ Cab, 258, auto, tilt, air con, tach, clock (works!) etc. Think this thing has every option that year. No rust, all there, extra ½ doors, blah blah blah. Arizona / So. Nevada Jeep.

No wife to fight about money (always a good option ;) - maybe later)

Anyway, this wont go up long freeway hills. All stock as it left the factory except HEI. Has Huge M/T Radials which dont help. I live ABOVE 7,000 feet, so this is really a turtle. Why do I keep singing "I'm bringing home a big ol' bumble bee" ?!?

Question(s): Looking for a 4.0 HO Head. Any ideas where to buy one? Pitfalls?
I am thinking of as new head, not a reman as I the Jeep is worth it.

At the same time I am looking at MFI. Has a Weber on it now. Better than CEC. Do I need to replace the intake & exhaust manifolds also? What are better makes? Headers?

And lastly, How do I know what Automatic this is? I am assuming a 999 Chrysler, as I think they only put GM 400's on th 304. (This is a 1981) - and this don't look like any 727 or 400 I've ever seen.

Later on, anyone ever use an O/D Unit for freeway?

Should I give up and buy a trailer and tow it behind my Grand Cherokee in Corinthian Leather Comfort? lol

Thanks, should be done by spring. Pics will follow.

Dave & my dogs Killer, Bruiser, Mamas & Pregnant Daisey.

John N

Addicted....Ex-SOA VP
CJ-8.com Member
SOA Member
Congrats and welcome to our sickness. Your trans should be a TF999, if stock. Your's is pretty much like mine started out. Re-gearing will probably give you the best "bang for your buck" since stock gears were 2.72's and you're trying to turn those 'big old M/Ts'. A Howell TBI kit may a much cheaper option the a multiport kit, but junkyard 4.0 heads can be had cheap, if you're doing your own work.

Good luck and enjoy!


Basic User
Sorta ½ to ¼ doing myself. I really need to hire a 18 inch tall troll who can bench press 325. Let him work on this....

Yes, Howell is what I was looking at - just said mfi, really meant single port...

BTW: I know someone who has a PRISTINE cj8 body wise for sale, engine way tired wtc, but 100% original -no dent - no rust body. It even runs, but more work than I wanna do. So I bought this low miler, altho we all know that does NOT mean less $$$ in repairs...