318/904 to 383/727

I know there is tons of info on here. I hate asking questions that have been answered a million times, but working 7 days a week I just dont have time to search for hours on end. Can someone please link some posts that can help answer some questions about this swap. 1970 Plymouth Satellite. I just bought a 1970 383 out if a Dodge Monaco, and am now trying to decide whether to go big block in my Satellite or stay small block to save a bunch of money. I just want a little more grunt out of my big old car. The fact I'm running 2.71 gears doesnt help.I know the tranny has to be changed, along with heavier torsion bars, transmission cross member, exhaust modifications, etc. But I'm not sure what else. Starter? I have a new 3 core large tube rad in it, but is that enough for a 325-350hp 383? Or just go non-period correct on a 360, and keep everything else the exact same. Any thoughts, advice, or links would be much appreciated. Ok, back to work. Thanks all. Car painted yesterday. Will cruise as is for a year before starting engine project.

Get yourself a stout small block and enjoy!
Maybe a poly 318 . You change those gears and you will be extremely impressed.
Put a shift kit in the trans . Make your the small block can breathe air flow in and out ignition system .
You'll be surprised .
Going big block is not going to be cheap
Not sure about that year k frame but ether a mount kit or k frame . Trans, drive shaft, front suspension needs to be beefed up , wiring harness needs replaced or modified to reach bb dist. You'll definitely need upgraded cooling system.
Parts cost more!

As you can tell I'm a small block fan I've had a big bad *** 440 4 speed it was fun but my god gas cost just to feed it!!!! My 340 4 speed setup is only shy about 100 hp
Or so and was much cheaper to build . And gets better mpg .my car also isn't noise heavy! The bb car wasn't as agile !

I like playing with my toys straight line is fun and all but a car that can hit a turn at 90mph and not make you mess your pants ! That's kinda fun too!

That’s a sweet car! I’m in The NWT doing the same exact thing to a ‘70 Coronet. Was 318/904 with 2.93 gears, now 440/727 with 3.23.

As said before, the biggest bang for the buck is to change the rear gears. 3.55-3.73 are good for both street and hi-way. A small block crate motor would probably be the most economical in the long run as opposed to building a used 360. New parts and a proven power combo on good crate motors.

We have done it like many. Starters are the same. It's nice to have the big torsion bars but not entirely necessary...you can give them a turn to compensate for the big block. It will sit lower even after giving it a crank...Aluminum engine parts, like intake and water pump housing will help. Chassis motor mounts should be the same and tranny crossmember is the same. A BB 727 has a longer tail shaft than a SB 904...you will need a shorter drive shaft or shorten yours. If you get a 727 and you want a center console make sure it has the two bolts on the tailshaft to mount the shifter rod. For a column shift either tailshaft should work. Exhaust manifolds or headers are both affordable and available, most exhaust manifolds work even off a BB truck. Radiator is easy to try...switch it later if it doesn't get the job done. I think a 383 polara water pump housing will work. They did make 2 different styles.
We had a 318 in our 72 satellite probably very similar to yours. We installed 4 barrel, headers and cam changed to 3.23. It ran pretty good. We then put a Switzer single turbocharger on it...this was 25 years ago. We tried running 2 much boost and kept blowing head gaskets and had terrible detonation problems. But when it didn't ping it screamed. They have lots of parts available now for turbo kits. However on our car we got sick of working on it and put a 440 in it. No regrets! Even though we are slower with our mild 440 vs our turbocharged 318 I love big blocks. I will have to dig through our photo album and find pictures of our 318 turbo pictures and pictures of our 72 satellite which we still have.
If you do a 360 you will still need a different torque converter then a 318..360 is balanced differently.

of course you can do it
Satellites came with both SBM and Both B and RB BBM's
Do you have disc brakes already and the largest torsion bars available stock are not really big enough for today's wide wheels with radial tires
rear sway from a Cordoba will work once you get the front end straightened out
so I'd do that B4 moving on motor if yours is running
gears are fine if you do mostly freeway crazing or stop and go or daily driver
lower for towing or "street" ride
408 sbm is much easier
on BBm you have a choice of water pumps left and right to match your radiator or you can have a rad shop switch the inlet if necessary
SBM will handle curves easier than BBM for same or less $$$ if you do curves
I forget if crossmember change is necessary
but all the swap info should be online
can you find a "donor" BBM B body? if you decide to go that direction
Donor would have to be 72 or earlier down to say 67-68 - check

Thanks all. Great info. Was doing some pricing, and right now it seems like the small block option is best. I will keep the 383 I have as I got it for cheap. It can sit on a stand. Regarding the 360's, what about the newer magnums 5.9's? Will they fit any different than the old 360's? I think a set of gears, like 3.55's would make a big difference. I have the smaller carrier on my 8 1/4, and would need to replace the unit in order to go steeper gears. 8 3/4 units around here are almost impossible to find, and are incredibly expensive. I'm only talking 325-350 horse anyway, and dont abuse my vehicles. Anyway, a couple more pics below. Thanks again.

The magnums are a more efficient engine. The head flow are a pretty big improvement over the old LA's stock port flow and make good hp..the hydraulic roller cam is also a nice addition. It's very likely you will have to purchase a aftermarket intake to adapt it back to a carb and buy a kit to change the serpentine belt back to the v belts. You also need a distributer with a mechanical advance but the old style will drop in. The flex plate and converter will need to be changed. Those parts add up. Someone could chime in too help you with the most economical way to do a magnum swap without buying a bunch of new parts.

But if you are looking for easy...I would keep with the older engine...get a LA 360 or even stay with a 318. If you put in 3.55s a 2200-2500 stall would be fun and be very drivable. Or spend more money and get a high performance converter that flashs high for your launch but is tight for street driving. If finding a good magnum engine gets expensive...I would rather put that money toward a good set of Edelbock heads for a old 318 or 360. Depends on what engine you can find that is a good starter. A stall converter can overcome the heavy car and tall gears and still be drivable....but when it comes to stall converters
..be careful...you usually get what you pay for!
...a 383 would really look good in there!Lol

slantsix64 just swapped an magnum and cam and carb into his A body
He called yesterday and says it runs great
He evidently has a stick valve body because he says burnouts in second gear- sorta like your stock gear (grin)
He is going to write up all the little details of his experience (cam timing- making up for undersized base circle etc)
see 318budge build and give him some encouragement to do the write up
Magnums work great
just drop one in for your use
they do not wear like carb 360's due to no fuel wash at start up
your rear end should take the power
Curious ?why change the serpentine belt?

wyrmrider said:

slantsix64 just swapped an magnum and cam and carb into his A body
He called yesterday and says it runs great
He evidently has a stick valve body because he says burnouts in second gear- sorta like your stock gear (grin)
He is going to write up all the little details of his experience (cam timing- making up for undersized base circle etc)
see 318budge build and give him some encouragement to do the write up
Magnums work great
just drop one in for your use
they do not wear like carb 360's due to no fuel wash at start up
your rear end should take the power
Curious ?why change the serpentine belt?[/QUOT

Click to expand...

I don't really have a opinion on the belts. If it was mine I would I would run the serpentine belts and have a modern ac and accessories.....unless I was trying to run the stock accessories...then v belts can be done...but you likely will have to buy some pulleys.

Mark1971are you looking for your best engine option while trying to avoid rebuilding one?

I’d go 383 and never look back. Rebuilt to stock it’s still 300 plus hp and will bolt right in.

Well, I've decided simply because of time and budget that the 383/727 option will have to wait. It's already been 6 years getting this car to this point, and I'd like to drive and enjoy it for a couple of years before parking it again for another major job. I will more than likely keep the 318/904 for now. The 318 needs some refreshing, and the 904 can be tightened up a bit. I think the gear change will help huge with that. Apparently, there are 2 carriers for the 8 1/4. If you have 2.71 or higher gears, that's the small carrier, which I have. So to go 3.55 for example, I'd need to change the carrier. I'm trying to track one down. The car will have the 383 eventually, just not for a while.

Well if it I could give you some encouragement to tinker with your 318...I will share my experience...

Our 72 satellite was a 318 and had 120,000 miles on it when I got it in high school...put headers dual exhaust on it first with the 2 barrel...noticeable performance gain...Then edelbrock performer and a 600 Holley. From 30 mph and faster it was surprising how good it ran. Beat on the car constantly and had lots of fun. The stock 904 went out first... so we finally pulled the motor apart to freshen it up...there was no babbit left on any of the bearings...they looked like they were bronze...buy it still ran good. 318's with there short strokes are good candidate to hone and rering they usually don't have much ring groove and your era of 318 they had harder blocks then later engines. Timing chain is really the only high wear item they had a crappy nylon gear. When I freshened the 318 up I had my first fail for installing two big of a cam. Advertised at 298 /308 in a stock 318... Lol. With 2.71s it did 75 in first...120 in second....but barely would spin the tires in the rain. Put a 214/224 @.05 cam after we finally spun a rod bearing with the big cam... installed 8 3/4 out of a 69 Polara and 3.23 posi. Ran a 15.6. @89 at the track. The car loved the highway had it to 6200 rpm in drive. It was surprising how quick it got there. The engine and tranny was identical to yours...rerung...stock heads, 340 springs, ,headers,4 barrel, 214/224 cam and 904 with a shift kit.. With a 2500 stall it would have gotten in the 14's...and the engine was just a freshened up version identical to yours. I didn't have any money and focused on what the car was born with...then in college my twin brother and I really got into cars...we ran a 70 cuda that ran mid 10s. Our 69 charger got a 510...and we put a turbocharger on the 318 combo described above. It was a riot. We might have had 500 bucks in our system..but had no way to control the boost. We replaced the felpro head gaskets like underwear. Even rebuilt another 318 and dished the pistons thinking something was warped. Then the last time we pulled the heads we noticed on every single cylinder the gasket was oval shaped and about to blow. Gave up and put a 440 in it.

Hey Curious, I'm not trying to avoid rebuilding an engine, just trying to budget my money and time. Thanks so much for the write up on your 318 experience. Honestly, if I wanted a fast car I wouldn't have bought a 3600 pound Satellite. Not that it cant be fast, but it just isn't my priority for this car. I want to cruise and have reliability, with a bit of fun mixed in. So this year will be the rest of assembly post painting, and just working bugs out of the existing engine/tranny. Possibly, if time allows, a rear carrier/gear change. Then next year see if I can track down a LA360 to build up to maybe 325 horse. Not period correct, but seems like money better spent than the 318.

8 3/4 is a much easier rear end to work with...the housing doesn't necessarily have to be out of a 70 b body you have options. It's easy to find 3.23 or 3.55 out of a pickup...new gears it's nice to do the 8 3/4 in a vice. It sucks to do a rear end out of the back cover like a 8 1/4....8 3/4 and Ford 9" are fun to work on compared to others...time wise 8 3/4 is a time saver...but I think the drive shaft would have to be shortened. Regardless, I would look look really really hard before I put time and resources in a 8 1/4..
I like the LA 360 in your car. I have A body cars...I wouldn't trade one of my B bodies for any of them. But I appreciate them all the same!