Mopar Big/Small block swap question

Assume you've got a B-Body Mopar from the early 60's with a carbureted 383. You have a choice of upgrading to a "current" big block or a small block. I'm not aware Chrysler has offered a full (with current electronics) EFI big block in a long, long time. I think the introduction of the Ram p/u in 2003 ended the big block, but I could be wrong.

What donor would you look at for a spirited daily driver? Truck Hemi? Charger?

How much weight difference between the old iron BIG block/iron head 383 and the current SMALL block, which I assume has iron block/aluminum heads?

I don't think Mother Mopar ever sold an EFI big block. It was one reason why the LA-based V10 was created. 360's and the Cummins were the highest power truck engines for a long time.

The B (361/383/400) and RB (413/426/440) big blocks were out in '78 as a condition of the government bailout. They were never produced with fuel injection or hooked up to an overdrive transmission except the 833 in cars.

Everything since is based on, shares a tranny bolt pattern with, and would be considered a small block.

Swapping anything except another B or RB will require engine, trans, exhaust, and cooling changes at a minimum, so an LS motor is about the same difficulty as anything Mopar.

stroker wrote: Assume you've got a B-Body Mopar from the early 60's with a carbureted 383. You have a choice of upgrading to a "current" big block or a small block. I'm not aware Chrysler has offered a full (with current electronics) EFI big block in a long, long time. I think the introduction of the Ram p/u in 2003 ended the big block, but I could be wrong.

Big blocks ended a good bit earlier than that - 2003 was the end of the road for the LA smallblock. Chrysler only offered a factory EFI option for the big block in one year: 1958. Not a typo.

The LA based Magnum smallblocks in the '90s are pretty cheap and not too difficult to find.

What donor would you look at for a spirited daily driver? Truck Hemi? Charger? How much weight difference between the old iron BIG block/iron head 383 and the current SMALL block, which I assume has iron block/aluminum heads?

Allpar has a good listing of the different varieties of the New Hemi. They also give its weight at 485 lbs without accessories. I've seen one estimate of a 383's weight at 625 lbs, but I'm not sure what was included.

Is there a car in this or just an engine? I thought he had an early-60's 383 on a stand.

pres589 wrote: Is there a car in this or just an engine? I thought he had an early-60's 383 on a stand.

The question supposes a car equipped with a early 60's big block 383 which you want to change to a "modern" engine.

How old of a '60's car are you thinking? Early, mid, or late? There were several changes that will bring up different challenges.

As covered earlier, other than the extremely rare '58 Bendix system, going EFI on a 383 is going to be an aftermarket conversion.

The most popular Mopar swap now is a 5.7 or 6.1L Hemi into the earlier cars.

Herb McCandless' 300 is a good example:

You'll need either the modern trans to go behind the Hemi, or a small block trans to bolt up behind it. The big block trans will not bolt up.

Following up on my previous 1960 Saratoga thread. I've got a couple of candidates and I'm trying to do my legwork. Dunno if it would be easier to simply run the original 383, swap to a 440 or look for a rolled Ram/Charger.

What are you wanting out of this thing? Parade / show, daily, something else? What's your budget for spending in the engine room on the car?

In reply to stroker:

Simplest would be to run the 383 if everything is there. They are very nice motors.

440 swap will mostly be straight forward. There are several things that don't carry over from the B to the RB, but not insurmountable. I need to brush up on some of the areas that might cause a problem for your swap.

A rolled Ram/Durango/Charger could be a nice donor. Don't expect to use the factory ECU. They don't adapt well to other vehicles. There are some folks making harnesses, but I think it would be easier to use an aftermarket controller.

Since the conditions for the '78 bailout, and the '58 EFI were both covered, as well as just about everything else, I''ll just leave an anecdote. Not only did Chrysler have to stop making big-blocks, but they had to destroy the tooling. The new RB-based Hemis that Mopar Performance has made are on all-new tooling, which is a lot of why they're so expensive.

Another anecdote: Chrysler sold factory space in Pennsylvania to Volkswagen, for the price of VW giving them drivetrains for three years. Thus you have a whole lot of Omni/Horizons made with 1.7l VW engines and a weirdball version of the 020 four-speed. And a very rare, very sought-after, VW bellhousing pattern version of the front-drive Torqueflite.

Knurled wrote: And a very rare, very sought-after, VW bellhousing pattern version of the front-drive Torqueflite.

I'll hijack my own thread. WTF was THAT used in?

Very early Omnis, useful for tdi k-car and minivan swaps.

I would keep the 383 and use any of the new EFI setups (throttle body style - not GM TBI though) and put in an overdrive trans or Gear Vendors. Enjoy the heck out of it.

Second choice would be Viper V10.

The bits apparently do exist to combine a Gear Vendor's O/D with the existing pushbutton TorqueFlite but it will take some pieces from later transmissions. 383 with the long cross-ram intake that was available around that same time period would look pretty killer. Not sure how much fun and cost would be involved in getting such a setup going and balanced, carbs or TBI.

I prefer the presmog 383 to the smogged 440. The latter has better torque, but the smaller engine runs more freely and produces better power unmodified.

I run two 383s - a 4 bbl version and a sixpack conversion, both 10.25 compression.

In reply to wspohn:

What do you do about the valve seats designed for leaded gas?

The Mopar castings had a higher nickle content than some of the other domestics of the time. They tend to tolerate low/no lead better. There are some lead additives out there, and some substitutes like what Redline offers.

If the engine needs a valve job, you can have hardened exhaust seats installed. The heads on your 383 should be the early ones with the 4 bolt valve covers and smaller ports & valves. You could swap the heads out to the unleaded '73-up 400/440 head. They are open chamber heads. You'll loose some compression, but it will still be a usable ratio. Not the optimistic 8.2:1 the '70's motors had.

oldopelguy wrote: Very early Omnis, useful for tdi k-car and minivan swaps.

Postal Jeeps, too, IIRC

One other thing I haven't seen mentioned here- If you go from big to small block, you will likely have to change or seiously modify the K-member.

I did some more research and it looks like the Saratoga may have drum brakes on all four corners. Would the '78 Magnum be a possible donor for a replacement engine (if necessary) and front spindles?

oldopelguy wrote: Very early Omnis, useful for tdi k-car and minivan swaps.

Forget that, it's useful for 4-cylinder VW drag racers who get tired of breaking the oh-too-fragile transverse manual transmissions.

stroker wrote: I did some more research and it looks like the Saratoga may have drum brakes on all four corners. Would the '78 Magnum be a possible donor for a replacement engine (if necessary) and front spindles?

I'll do a little checking, but I think they might work. I'll see if I can scare up some info. I think guys have used the lowering spindles designed for the FMJ spindle (that Magnum uses the same spindle as the F-M-J bodies) on the early cars.

Please tell me the Magnum is rotted away in a junkyard, not a rust-free vehicle.

Rob_Mopar wrote:

stroker wrote: I did some more research and it looks like the Saratoga may have drum brakes on all four corners. Would the '78 Magnum be a possible donor for a replacement engine (if necessary) and front spindles?

I'll do a little checking, but I think they might work. I'll see if I can scare up some info. I think guys have used the lowering spindles designed for the FMJ spindle (that Magnum uses the same spindle as the F-M-J bodies) on the early cars. Please tell me the Magnum is rotted away in a junkyard, not a rust-free vehicle.

Let's assume the Magnum is a no-go. What later B-bodies might be potential spindle donors?

Me I'd keep the 383 or use a 440 but you'll likely need different exhaust manifolds for the 440 to avoid the steering column interference and depending on if its power steer or not you might need the connector section to avoid baking the slip joint. So keep the 383.