Engine swap should I go 360 or 383

Big_John said:
I understand completely. Some guys think this stuff is made of gold.

Just for the sake of discussion with anyone else contemplating swapping, here is a decent list of interchangeable parts with the LA and the Poly. Poly 318 Polyspherical Parts Interchange - Poly318.com
Click to expand...
A VERY interesting and informative link! Many differences, like I remember reading about ages ago, but not quite as simple as some (as UTG) seem to make them out to be. More differences than I ever suspected! As some design "hard points" still live on today in Gen III Hemi architecture.

Bad thing is that with all of the "way over-engineered" rear of the crankshaft things Chrysler did back then, it seems that almost NONE of the early blocks can easily accept modern transmission behind them, unlike the Chevy V-8 competition can, which is a shame, to me. Some of the same mis-steps could have saved the corp money while making their non-Hemi engines more attractive in the process. Oh well . . .

Enjoy!
CBODY67
 
Most people think backwards on automotive development.

Instead think forward. Pick a year to start, like 1955. Now this will show you they didn't have a 727 yet and didn't know how great they would be. So they were stuck with powerflights and cast iron torqueflight.
 
Another place to look for poly parts that aren't expensive is on CL in the boat parts section.
 
Imo I'd find a cheap 360 to pep it up and then focus on Grandpa's roadrunner sitting there!
I also have a red 72, though it's a clone with the correct grill and such
 
furious70 said:
Imo I'd find a cheap 360 to pep it up and then focus on Grandpa's roadrunner sitting there!
I also have a red 72, though it's a clone with the correct grill and such
Click to expand...
Yea we've been working on the road runner rebuilt a 440 and trans dropped it in after it got back from paint we are just buttoning up the engine bay then we start redoing the interior. But yea I'm trying to bring some life to my fury as well we rebuilt and sold a 72 duster so I'm trying to put some time into the fury to get it where I want it
 
I don't know anything about the poly.
I have had a lot of stock 360 two-barrel motors in big 74 and later Mopar products. They worked very well. Plenty of usable torque. I never modified a 360.

The 318 and 360 Magnum motors made from 1991 forward have been even better. Both make "a lot more power" than the earlier two-barrel motors. I have run them to 300k plus miles and never have the valve cover off of one, and never put less than 175k miles on one. The 318 Magnum doesn't get up on the cam until 3200 rpm. Both like 3.55 rear gear, and the 3.91 with the overdrive trans.

My 360 Magnum 1997 b2500 conversion van with 3.55 rear gets 14 to 18 mpg and accelerates better than my late 60s 383 two-barrel C bodies did. My 98 B3500 with the 360 Magnum motor has "much" more pulling power with a 4.10 rear gear. 12 to 16 mpg.

My 3800 pound plus driver and gas 93 Dakota 318 Magnum with 3.91 rear accelerates faster than my 68 383 Road Runner with the same rear did. It gets 15 to 18 mpg.

I would NOT ditch the Magnum simple direct injection fuel system and convert a Magnum to carburetor.
I would definitely try to use the big 518 (it's a 727 plus added on overdrive tail housing) that was an early (91 to 95 ?) standalone all hydraulic (no computer) 4 speed auto overdrive trans, along with a 3.91 or 4.10 rear gear in a C body if I went with the 360 Magnum.
Don't know if the Mopar shorty stainless headers fit.
 
CBODY67 said:
Explained in the Poly318 link @Big_John supplied above. There were "Marine" versions with an "M" cast into the cyl heads or whatever.

CBODY67
Click to expand...
Understood I will look into what I can get out of the poly more in depth while I search for a 360 la, so I can see which route I'll take but Im thinking about doing a stroked 360 and just holding on to the 383 I have till a later date or a different project but time will.
 
There is a
bigfury3 said:
Understood I will look into what I can get out of the poly more in depth while I search for a 360 la, so I can see which route I'll take but Im thinking about doing a stroked 360 and just holding on to the 383 I have till a later date or a different project but time will.
Click to expand...

The 360 LA is probably not hard to come by. I purchased a good 360 four barrel for $300 a few months ago. I think it's from a 1980 Plymouth Volare cop car.
Didn't want it, somebody needed a little money, so. Anyway, looking for a 70s Dart/Valiant to put it in. Because of fond 69 GTS memories.
 
I'd stick with a small block, less hassle, minimal to no modifications required. Even better would be a late model Magnum small block with trans and computer/wiring harness from a pickup truck, keep the EFI stock for minimal hassles. That way you get power, torque AND gas mileage, not to mention cleaner emissions to save the planet, even without a cat convertor.

Lots of small block crate motors to choose from for a direct drop-in replacement if you have coin. While a bit more expensive than a junkyard motor you could build up yourself, a crate motor gets it running & back on the road faster, MAY come with a warrantee (if installed by a competent shop) & involve less hassle than a big block conversion.

My '02 Ram 1500 with a 4.7 Magnum/OD trans runs circles around, & gets better mileage (13 town/17 hwy), than my 73 Newport with a built 400 (Project Turd: doggy doo brown & crappy gas mileage, 8 MPG on a GOOD day if I can keep my foot out of it, not an easy thing to do when it sounds so sweet when you stand on it). I have considered a swap but decided against it, I'd loose the character & musclecar sound of that I've fallen in love with. I've decided to save up and spring for a stroker crank & aluminum heads from 440Source and a bolt on GearVendors OD unit with a Holley Stealth 4bbl EFI unit. She was born with a big block between the fenders & I want to keep it that way. Stroked with painted heads & Holley throttle body will retain the stock appearance, & the GearVendors OD won't require massaging or cutting up the floorpan, just a shorter driveshaft. I'm looking at 8 grand for it all, in the last year I've scratched up $3600 so far. Goals.

If I were you, I'd sell the 383 & 318 to finance the 360 or Magnum swap. Your wife/GF/domestic partner wouldn't mind the extra garage space either.
 
My $.02: stay with the small block so you don't have to swap the trans.
Swap the stater support in the trans to use a newer torque converter, a 360 TC won't install in a '66 trans.
Get the different driver's side motor mount isolatior (340s and 360s use a different one) swap exhaust manifolds for the LA motor
Have fun!
I just remembered the 65 has a different drivers motor mount, may throw a wrench in the works.
 
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So i found a 4barrel 360 and 727 trans from a 76 motorhome for $800 question is would the trans fit in my fury so I could just drop them in together?
 
Depends, does that MH trans have the drum brake emergency brake hanging off the back?
 
Yes that doesn't fit in cars. It could also have the short tail housing that won't work for a car
 
How bad is it? My dad had a fury wagon with a poly in it that ran really good. It wasn’t a rocket, but it was smooth and torquey and picked up speed pretty rapidly. It just felt like it made power.

I would make sure the timing is set as good as can be (crank it until it pings and back it off a couple degrees), adjust the valves, and go from there. Maybe give it a compression check and leak down. I think a poly could be made to run better than a similar LA due to the canted valve heads. A 4 barrel intake, some better exhaust manifolds or headers, and maybe a cam and I bet it would be quite the difference.

Don’t get me wrong, I’m a huge fan of 360’s but I’d throw a few dollars at the poly myself. Especially if it’s already a good runner. You’d be dollars and work ahead to make the poly work. Plus you’d have minimal downtime.
Travis..
 
Dads300 said:
How bad is it? My dad had a fury wagon with a poly in it that ran really good. It wasn’t a rocket, but it was smooth and torquey and picked up speed pretty rapidly. It just felt like it made power.

I would make sure the timing is set as good as can be (crank it until it pings and back it off a couple degrees), adjust the valves, and go from there. Maybe give it a compression check and leak down. I think a poly could be made to run better than a similar LA due to the canted valve heads. A 4 barrel intake, some better exhaust manifolds or headers, and maybe a cam and I bet it would be quite the difference.

Don’t get me wrong, I’m a huge fan of 360’s but I’d throw a few dollars at the poly myself. Especially if it’s already a good runner. You’d be dollars and work ahead to make the poly work. Plus you’d have minimal downtime.
Travis..
Click to expand...
If I could find a 4 barrel intake and other go fast parts for the poly I would, but because of the rarity and people thinking the parts the have are worth their weight in gold it would be more work than just getting a 360. I live in socal so it's not like we have very many old cars let alone parts floating around.

If I could I would build the poly trust me but the parts are to hard to find id rather just get a 360 so I can stroke it or do whatever my little heart desires. I respect your opinion but unless anyone on here has a line on some parts for the poly(4barrel/carb etc.) I'm probably do 360
 
SoCal is the birthplace of hot rodding, just because you don’t see old cars every day doesn’t mean there aren’t tons of them around. You need to talk to some old timers and find someone with a manifold in their parts hoard. Marketplace isn’t where you’re going to find one at a reasonable price, that’s where the kid who got it cheap from and old guy is trying to capitalize. Like I said, I’m a huge fan of 360’s but those poly 318’s are sweet running engines. It’s your car though, so you pays your money and take your chances.
Travis..
 
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