V6 options for power???

[Geminiroq]

Hey guys...quick question.

As you know, or dont know, by now...I am looking for my first FSJ.

I have come across a ton of them in all various conditions and price ranges.

I came across a really nice cherokee but it has a V6 in it.

What kind of power can I expect out of it and can it be upgraded to pull decent power out of it???

Also.....what would be the MPG on this v6 compared to a 360 or 401 v8?

Any and all advice is much appreciated

Also if you have a nice rig that you are wanting to sell....send me a PM and we can talk.

Thanks again,

Ronnie

[waggy401]

If you found a V-6, it is either some odd swap or it's not a FSJ. That being said, if it's a modern fuel-injected V-6 it is likely to have more power than a stock AMC V-8.

My guess is that the owner made a mistake, and it is one of the various inline 6 engines. I don't have much experience with sixes, but in general they tend to have pretty good torque, but lack in horsepower. They also tend to get better gas mileage, being smaller displacement. Many people here have them and are happy with them. They are tough, but certainly not speed demons. It all depends on what you are looking for it to do.

[Geminiroq]

It is actually in a 1982 cherokee.

I am trying to maximize as much horsepower and torque that I can get out of it.

I want to tow a boat with it, use it as a daily driver and a trail rig.

Thank you,

Ronnie

[joe]

Odds are it's a 258 inline six. Be surprised how many folks call all six cylinder motors V6's even if they're inlines....<shurg>.
The 258 is a good motor. Not fast but tough. As is for a DD it'd be fine. For trail and towing the axle ratios are going to suck in the 80's era especially if it's the more common 2.72 ratio. Even if you installed a beasty mega HP V8 it's still going to suck towing with those axle gears. If the motor is solid leave it alone except maybe de-smogging it(82+ 258's are horribly smogged), and add a weber carb, HEI dizzy. Spend the big money on decent axle gearing.

[Geminiroq]

What will the weber carb do for perfomance and what is a HEI dizzy??

Thank you...

[shepherdskeep]

dizzy = distributor

[joe]

Originally Posted by Geminiroq

What will the weber carb do for perfomance and what is a HEI dizzy??

Thank you...

I see you're in the PRC so all bets are off for de-smogging/modifying much. The stock Carter BBD carb on those things I think must be a Brit design? Our brothers on the island have never figured out how to mix fuel/air...ever.
Any carb would be an improvement performance/reliability wise. The Weber is the top-o-the-line IMO but a Motorcraft 2100 will be cheaper and also good. HEI is an electronic ign. used by GM and a distributor from a 250 inline six Chev can be easily modified/swapped into an AMC 258. Much better system than stock. Zack at Z&M Jeeps sells the dizzy or you can do your own from boneyard parts. The 258 is a solid reliable tractor motor and can use some freshening up but don't put big bucks in it trying to make it a hot rod because it's still a tractor motor. I'm a big fan of the 258's but still accept them for what they are. A good long running easy to work on, cheap to get parts for reliable tractor motor.

[Geminiroq]

Joe,

How can I find out what gear ratio this truck has?

Thank you,

Ronnie

[joe]

Originally Posted by Geminiroq

Joe,

How can I find out what gear ratio this truck has?

Thank you,

Ronnie

Ronnie,
On the rear axle theres a flat boss that's part of the cast iron differential casting where the right side axle tube presses in. On it and next to the big dowel pin hole will be stamped a letter code. It's facing toward the rear of the rig and you may have to scrape/sand some crud to see it. "D" will be 2.73 gears and "B" will be 3.31's. Those were the only two options in the 80+ era. If you have the 3.31's and depending on how heavy your boat is you may be able to live with it but you won't like the 2.73's for towing.

edit: check this diagram out. http://www.ifsja.org/tech/axle/axleid.html it should help locate the stamped area but "ignore the chart...it's wrong" Those codes are for little jeeps not FJS's.

[Geminiroq]

Joe,

Thanks again for your expertise!!

If it is the lower gear set....what is the cost of upgrading to the higher number gear set?

Thanks again!

Ronnie

[tgreese]

The stock Carter BBD carburetor is troublesome, but you can buy a fuel injection kit from Howell that will pass a CA smog check (has a CARB number). Not cheap though, about $1000 for the kit.

The GM distributor would not be allowed (if they noticed), but you can do the TFI upgrade on your existing Motorcraft Duraspark system.

[joe]

Originally Posted by Geminiroq

If it is the lower gear set....what is the cost of upgrading to the higher number gear set?

Ronnie

If you had a "qualified" drive line shop do it(DO NOT GO TO THE DEALER) realistically prolly $1500 for the front and rear out the door. You could do it for prolly 1/2 that but it's not a job for a brand new mechanic and there are a couple $$$ tools involved.
If you go that route go at least 3.73 gears. Lower(higher numerically) if your boat is huge or you decide on big tires. I personally like 3.73's for a good do-all tow/trail/hwy compromise ratio again unless running really big tires.

[Geminiroq]

Joe,

The boat is only a couple thousand pounds...and could I just swap out the axles from a boneyard?

Thank you,

Ronnie

[joe]

Originally Posted by Geminiroq

Joe,

The boat is only a couple thousand pounds...and could I just swap out the axles from a boneyard?

Thank you,

Ronnie

Yeah you could find a set of 3.31's from an 80+ Wag or Chero in a yard. Anything other than that you'd have to move up to a 80+ J20 donor w/3.73's but now you're talking suspension/body mods to get them under a Wag. The 80+ Wag/Chero axles only came in the two ratios mentioned. If you went to pre-80 era rigs the differentials would be in the wrong location and now we're into trans and transfer case swaps too. Lot less time/grief just regearing your present axles unless you're building a badazz trail/tow rig. If you can live with 3.31's though you should be able to find a complete pair for $300 or less for both from a donor rig. Include shipping into that though.
On the other hand if you haven't yet bought this rig you may just want to keep shopping for a Wag w/3.31's? Lotsa Wags around for sale especially with gaso over $3/gal.

[Geminiroq]

Joe,

Your awsome!!!

Thanks for the advise!!

Ronnie

[Kali]

I have 4.10s in my truck with a somewhat tired 258 but you'd never know it was tired! If youre going to tow, I think 4.10s would be the way to go, unless you are going with a short tire. Id say 3.73 with 31s or smaller, and 4.10s with 32s and up.