Has anyone performed a V8 swap into a 1981 J body ?

[Navajas]

I was just wanting to convert my 225 slant 6 to a more substantial V8. Either a 318 or a 360, Since the J bodies have the transverse cross member, would I have to procure a V8 K member ? And what else would I have to swap ? What should I go with the 5.9 or the 5.2 ? I'm kind of partial to the cubes of the 5.9 but have never owned anything but a 225 and a 440 ci. Any help or advice would be much obliged.

[270SE]

Either one would work. The 318 can get 2-3 or so better mpg than a 360 all else equal. The 360s all came with better heads and carbs. Some 318s from the '80s also had those same better heads and carbs though.

You don't have to get a V8 K member but they are easy to find since F and M bodies use the same K member. Later M bodies only came with 318s.

You'll need the trans with the motor, doesn't matter if you want to use a 904-based or 727, stick, or overdrive auto. The slant six trans won't bolt to a small block. The rear may or may not hold up well if it's stock, they did put 7-1/4s behind 318s but they didn't always do well, if you just drive it you can be okay for longer. You'll also need the right trans linkage for the carb you plan to run, 2 or 4 barrel. You should be able to get everything you need from a V8 equipped F, J, or M body car.

[CudaZappa]

if you don't want to swap k-frames, Schumacher Creative Services will have what you need. But if you need to rebuild your front end, then the K-swap is the way to go.

[Navajas]

Either one would work. The 318 can get 2-3 or so better mpg than a 360 all else equal. The 360s all came with better heads and carbs. Some 318s from the '80s also had those same better heads and carbs though.

You don't have to get a V8 K member but they are easy to find since F and M bodies use the same K member. Later M bodies only came with 318s.

You'll need the trans with the motor, doesn't matter if you want to use a 904-based or 727, stick, or overdrive auto. The slant six trans won't bolt to a small block. The rear may or may not hold up well if it's stock, they did put 7-1/4s behind 318s but they didn't always do well, if you just drive it you can be okay for longer. You'll also need the right trans linkage for the carb you plan to run, 2 or 4 barrel. You should be able to get everything you need from a V8 equipped F, J, or M body car.

I thought the A904 would bolt up to the 273,318 and the 360 ? And I'm not familiar with J Bodies, I've only owned a 74 A body and a 73 B body....When I read the stats on Wikipedia, it said tt the 225 was standard ad the 5.2 was optional and so was the 5.9 although those are rare. I noticed the only trans mentioned was the A904 so I figured they were compatible, not necessary survivable under strenuous conditions, but compatible for compatibilities sake, I fiured the rear end has to go since it is a pretty low gear since I can crawl up any hill here in Az and the gas mileage is pretty terrible,all are telltale signs that it is a torquer, I have no idea what ratio, do all 8 3/4 Mopar rears have the Suregrip ? I had a friend tell me that if it didn't , It wouldn't be hard to do. I didn't buy the car, my parents did, So I wanna swap the dead block for something with teeth since the 225 a a pain in the @$$ to work on and if it's not friendlier on gas than a V8, then out it's gonna go. It's only 2 redeeming features is that it's black and a 2 door, I just wanna do a LS grille and blacked out Aftermarket rims like 15's on all 4 sides, and make it a sleeper like my 74 Dart with a 440. Thanx

---------- Post added at 07:16 PM ---------- Previous post was at 07:07 PM ----------

if you don't want to swap k-frames, Schumacher Creative Services will have what you need. But if you need to rebuild your front end, then the K-swap is the way to go.

Thanx for the link, I've heard of Schumacher, but since the loss of my 440 74 Dart, I've lost interest in the Mopar Community since it just made me envious to see other people indulging in the hobby and I couldn' because of my self-inflicted circumstances. Th Cordoba has been sitting dead for 5 years and I wanna mod it out to suit my visceral yet practical tastes, No NOS, No dual quad intakes, no stinkbug stances and no gaudy Mexican mods (I live in Az where the Mexicans have rims that poke out 8 inches past the fenders and dual exhausts with 4 tips on each tailpipe!) Just pure sleeper appeal since it was a grocery getter.

[CudaZappa]

I thought the A904 would bolt up to the 273,318 and the 360 ? And I'm not familiar with J Bodies, I've only owned a 74 A body and a 73 B body....When I read the stats on Wikipedia, it said tt the 225 was standard ad the 5.2 was optional and so was the 5.9 although those are rare. I noticed the only trans mentioned was the A904 so I figured they were compatible, not necessary survivable under strenuous conditions, but compatible for compatibilities sake, I figured the rear end has to go since it is a pretty low gear since I can crawl up any hill here in Az and the gas mileage is pretty terrible,all are telltale signs that it is a torquer, I have no idea what ratio, do all 8 3/4 Mopar rears have the Suregrip ? I had a friend tell me that if it didn't , It wouldn't be hard to do. I didn't buy the car, my parents did, So I wanna swap the dead block for something with teeth since the 225 a a pain in the @$$ to work on and if it's not friendlier on gas than a V8, then out it's gonna go. It's only 2 redeeming features is that it's black and a 2 door, I just wanna do a LS grille and blacked out Aftermarket rims like 15's on all 4 sides, and make it a sleeper like my 74 Dart with a 440. Thanx

the \6 trans has most importantly a different bellhousing than any other engine, so you need a trans to match.

your car probably has a 7.25 rear or (less likely) an 8.25. They stopped making 8.75s in 1974, and yes, not all were suregrip. the 67-70 B-body rear is a pretty easy swap. You'll need the driveshaft from an 8.25 or yours shortened.

the 360 was a 1 year only engine (80) and they are rare indeed.

[270SE]

A V8 904 would bolt up to 273, 318, 340, 360. Along with a few other motors. The small blocks, slant six, and big blocks all had different bell housings. There's two varients of the 904, the 998 and the 999 which

The 360 was '80 only for the J bodies.

8-3/4s don't all have sure-grip and they weren't available in J bodies. The 8-1/4 and 7-1/4 were both offered in the J bodies and both could get sure-grips. The 7-1/4 is basically useless without sure-grip if you are going to run it hard, if you are just commuting with it you may get a decent number of miles out of it.

The easy B rears to swap in are '66-'70. '66-68 8-3/4s were standard in B bodies, '69 and '70 they were optional. (not guaranteed)

[DobaMark]

The 727 was used in the J bodies, at least those rare 1980 ones with the 360-4.

You may need to widen the radiator opening. The slant 6 used a 19" (no AC) or 22" (with AC) radiator. Non-AC V8s used the 22" radiator while those with AC or HD options used a 26" radiator. I'd certainly include an upgrade to the 26" radiator if I was doing the swap.

[270SE]

The 727 was used in the J bodies, at least those rare 1980 ones with the 360-4.

You may need to widen the radiator opening. The slant 6 used a 19" (no AC) or 22" (with AC) radiator. Non-AC V8s used the 22" radiator while those with AC or HD options used a 26" radiator. I'd certainly include an upgrade to the 26" radiator if I was doing the swap.

Forgot about that, only '80 360-4s I've seen were 727 cars.

So they didn't use the 28" radiator like many F and M bodies? (that really wide thin one)

[DobaMark]

So they didn't use the 28" radiator like many F and M bodies? (that really wide thin one)

I suspect the 26" radiator and the 28" one are the same thing, just different ways of measuring it, like core width only vs. mounting width. The part number for the 26" (the way Chrysler measured it) in the aftermarket covers all F/J/M units throughout the production tun from 1976 to 1989 for 318 (with AC) and 360 applications when available.

[270SE]

And that's why I've never heard of a 22". 318 w/o A/C was pretty rare.

I think you may be right. There's a 26" that's typically a shade over an inch or more thick and a 28" that's either thick as crap or around 3/4" thick. That's what I have and have seen. The 26" was really common in B bodies, C bodies and E bodies but I have seen them in '80s trucks. Recently saw one in a '73 Fury 360 A/C- that was a bit of a surprise.

The 19" sounds a lot like the old slant A body radiator, the 22 was the typical V8 A body until '73 or so. The 22 was also used in a lot of non-A/C B and E bodies.

[Bill55AZ]

Where are you in AZ? I am in Peoria right now, spend summers in Utah. I have a v8 Kframe, powder coated in Utah...also a bit of knowledge about the FMJ bodies. I actually wrote some articles for the forum some years back, don't know if they are still available...
heading out of town for a week this afternoon, contact me later, I have a lot of parts to upgrade suspension and brakes, also have a nice looking 80 Diplomat coupe with slant 6 to show off....under 90K miles and pretty.
BTW, if you get a 999 version of the 904, (from a pre overdrive dakota or d150) and have a tranny shop add a few special parts, it is about as good as the 727, as long as you aren't drag racing. Forget about overdrive trannies, you need to do body work to make it fit.


wmemoore1@comcast.net

[Navajas]

How would I spot a 66-68 Suregripped 8 3/4 short of removing the pumkin cover ? I got a 74 360 today for $ 200 from my ex co worker who had no use for it since he had just gotten a 68 Polara w/383 and is swapping the 383 for a 440 w/ tunnel ram and Lunati cam and an A-833. Thank you all for all of your input. Oh and my 225 came with an A/C which means 26 inch radiator ? So that will be one less thing to worry about ?,eh? How tight will the engine bay be w/ the 360, and power steering. I just wanna have room to change spark plugs without removing fenders or drilling holes for my socket and ratchet. It's one of my pet peeves, getting access to spark plugs in tight,cramped bays. My dad has a 72 Mercury Comet w/ 302 and that is a real hemorrhoid to perform tune ups on. Should I just go w/ Mustang II style rack and Pinion setup ?

[CudaZappa]

Good deal on the motor.

As for the rear end, unless it has a SG tag ("use special additive") or if you can lock the pinion in place and try to turn one wheel (if its SG it will be difficult) those are the easiest ways to tell. BTW: don't knock a one legger. It'll get you up and running quicker and much cheaper while you hunt the bargain SG third member or spend time saving up for new.

The radiatior will be fine, and for room you'll have plenty. I've heard 440 swaps are a nightmare for fitting.

As for going to a Mustang 2 setup, don't know why'd you wanna do that? The factory mopar steering is actually quite good unless you're serious about competing against a clock.

[270SE]

Oh, the pumpkin will say SG after the gear ratio. It's right after the P/N. Someone could have swapped an SG into a non-SG pumpkin. It's not really desirable enough to worry about. If you are worried about sure-grip then you probably shouldn't bother with an 8.75". That's where it goes from not much to more $$$ than its worth.

So far what I understand on 440 swaps is mounts which aren't so hard in an M. Power brake booster has to be changed to a smaller one. And the trans has to mate to it. (727 BBs grow on trees) The fenderwell-exhaust manifold clearance is likely to be very tight though. Obviously not ideal for a street car.

'74 360 is a good piece. This is largely similar to the 1973 340 which made an honest 285hp. The intake, cam, carb, and stroke were different.

No clearance issues with the 360 and P/S. 360 fits the same as a 318, you can run headers with P/S, P/B, and A/C no problems. Or stock manifolds, whichever floats your boat.

No reason or benefit to go with a Mustang II setup.

[Navajas]

Good deal on the motor.

As for the rear end, unless it has a SG tag ("use special additive") or if you can lock the pinion in place and try to turn one wheel (if its SG it will be difficult) those are the easiest ways to tell. BTW: don't knock a one legger. It'll get you up and running quicker and much cheaper while you hunt the bargain SG third member or spend time saving up for new.

The radiatior will be fine, and for room you'll have plenty. I've heard 440 swaps are a nightmare for fitting.

As for going to a Mustang 2 setup, don't know why'd you wanna do that? The factory mopar steering is actually quite good unless you're serious about competing against a clock.

Well, for one I was concerned about clearance issues with the p. steering setup, and header clearance as well as sparking plug access. If the reservoir was the easiest way to go to free up some room, and lighten up the front end while also ommiting one more pulley for better fuel economy. Another ? How big of a cam can I run with , I'm assuming are stock heads , without breaking anything or swapping in a higher stall Torque Converter or better heads ? I just wanna get a good carb and intake and a decent performing engine, In the future, I'd like to go with a TBI fuelie setup like Edelbrock or Holly offers, some Mopar Performance Heads and a Purple Cam, and if $ permits, maybe a A 833. I was doing some footwork on Schumacher's Conversion kits and DL'ed the instructions, It seems the /6 motor mount perches are 2 3/8 taller than a V8 equipped perch and requires me to drill a 9/16 hole 1 inch below the perch mount on both sides and cut the upper perch mounts off in a semi-circle. The "Conversion kit" seems to only have motor mounts. So it would be incorrect to advertise as a kit. It should just say /6 to 340-360 conversion motor mounts. The instructions also recommend an upgrade to electronic ignition if not already equipped. My co-worker suggested I run a stock profile 340 cam and despite the resulting low compression, it would run the way I'm shooting for.

---------- Post added at 10:31 PM ---------- Previous post was at 10:20 PM ----------

How hard would that be to accomplish ? The Schumacher /6 con. kit strongly recommends an upgrade i the vehicle is equippe wih 9inch drums. Well, If that's what I have and I have to go bigger...Then why not just go all the way and get discs ? But what year and model would have the ideal setup that I could cannibolize ?