258 to 304

is this a real bolt on ?
i know that only one motormount has to be mod., is this true.

iam asking because i have bought so many bolt on things and not even one was close to a bolt on.

i just want to know bevore.

i have a cj6 1979 with 4.2 and t-150.

gerald

 

Yes, the two engines have the same bellhousing pattern, and the 304 will bolt up to the bellhousing in place of the 258. You will need a 304 with a 304 flywheel - the flywheel is specific to that engine.

Re the frame towers (motor mounts), that may or may not be true for the '76 or later CJs. The V8-style motor mounts should bolt to the frame though.

You'll need some wiring and plumbing changes.

Personally I would go with a 4.0L HO swap instead of a V8, and use the excellent Mopar multipoint fuel injection. 4.0L donor vehicles are cheap and plentiful here in the USA. Fuel economy will be way better with the 4.0L, and power is about the same as the 360 V8.

 

thx
i know, but i want a v8

i need to have my car street legal and this is the only way because it was a option 1979.

gerald

 

I would do the 4.0 head swap then instead of the 304. They are dogs. If you want V8 sound do the split header and dual glass packed exhaust. That's what I run and it definitely sounds like a V8. Plus, you could fuel inject it as well.

 

Isn't the 4.0 HO allready a multiport fuel injection?

 

laws there are most likely different (see post 3) if it didn't come from the factory that way it probably cant be added

 

Yeah. Only bummer is the wiring harness jungle. Trick is to carefully remove the entire wiring harness from the donor vehicle, then send it off to Hotwire Auto to be pared down into a Hot Rod harness w/ only a few connections. Hotwire charges around $600-$800 for this depending on condition of the original harness. Much less than what the Mopar conversion costs.

By the way - the Howell injection is half as expensive as the Mopar one and I honestly like it better.

 

A 4.0 with a HotWire harness....
Dummy, I know where to fine one of those

I want to do that conversion as well.
Seriously, I'm considering buying a mid 90's Cherokee for my kids to learn to drive in and then when they're done learning... chop chop! I'll have a new motor for my 74 CJ5. I'm assuming it'll bolt up to a T-18.

Not to hijack, just putting in my $.02 for the 4.0

 

I'll sorta continue the hijack, although it's somewhat on-topic. How's that thing doing for you? How's the drivability, power, economy? I can barely remember what I did in that drivetrain, but I think it was a '91 or '93 or something like that 4.0L with an Edelbrock header, 21- or 24-lb/hr injectors (or something like that - Arizona TPI, I think), NV3550, and 4.56 gears.

Never even got to drive that one other than poking up and down my street very briefly.

I'm not considering swapping out the 304, but I am thinking - my '73 Commando has a 150hp/245lb-ft 304 V-8. That 4.0L in the Gladiator was factory rated at 190hp/225lb-ft. With the mods and better exhaust it was probably up near 200-210hp and 250lb-ft. Funny how close they are.

 

Hesco also sells a complete harness for around $400. It's just not worth $800-900 in my opinion for HotWire to cut down a factory harness. With OBD I there are only 5 wires required to run. Just pick a junkyard harness and have at it. The diagrams are well documented on the net. Painless also sells a complete harness if you can't find a stock junkyard one, but theirs is pricey.

 

I TOTALLY agree! Sure, you can get the same power and torque out of a 4.0L, in fact it may be WAY more reliable and modern....but you DON'T get the "puck-et-a, puck-et-a, puck-et-a!!"

Have you thought about a 360 or a 401? I have the 304 now and it's nice, but there's PLENTY of room for growth.

 

I haven't checked since I did the Hotwire, but I did call Hesco first and Bennie told me they weren't doing the '96-earlier harnesses anymore because the company who made the connectors for them went out of business. He recommended I either use a '97-'99 engine or let Hesco pare down the factory harness at 6-hours (minimum) labor at $109/hr.

The Hotwire Auto one was really the best game in town and they'll customize the harness for you at little-to-no extra cost to run stuff like cruise control, electric wipers, fuel pump, electric fan(s), A/C, 4x4 indicators, or whatever else you wanna roll into the harness.

Maybe Hesco found a new source for the hotrod harnesses connections. 5-wire hookup would be sweet, but I was really, really happy with the Hotwire one. And again - maybe prices have climbed, but it was around $600-$800 depending on how many bells and whistles you wanted to roll into the harness.

 

Driveability? A definite daily driver, I've put a few thousand miles on it.
Power? Very snappy when empty, touch the thorottle around a corner and the inside tire will report. Loaded? It feels the weight, I was able to keep freeway speeds up Cajon pass with firewood, ice chests, spare fuel, camping gear, etc... had to run in fourth gear and wind it up a bit. Not sure how fast it will go but I've briefly touched 80mph.
Economical? WAY! The fuel tank leaks more than the motor burns But that's another story...
Head Turner? Oh Yeah, but you didn't ask that. :twisted:
The truck has had and has it's share of quirks and problems, but none so far related to the motor/ wiring harness swap.
It has told me that I want a 4.0 in the CJ5, that is for sure.

 

sure, but here they think they selling gold if you find one 401

i want stay close to original , and i look for a list with all the options in 79 for my cj6

a couple of friend have the 4.0 ho and one friend has the zj 5.2
in his cj7, but i like the old v8

gerald

 

I guess I was talking about my situation I guess I have EFI on mine already and would like to do the 4.0 head swap.

If you are going V8, pony up to the 360...