Poly318 to 360 swap

[mgriffith]

I posed a question close to this a year or more ago, but that deal didn't pan out. And since I have new questions, here is a modified repost.

I've got a 65 Coronet w/ stock poly and the 727 3 speed auto. I've got a new lead on a really good early 70s 360. The engine is ready to bolt in. Headers, Holly 4 barrel, MSD electronic ignition, etc.

I've been told that the 360 is an externally balanced engine, but really don't know what that means! Can I use the 727 tranny that's in my car now with the new engine? If so, what do I need to do to it; new torque converter maybe?

Known problems.
1) engine mounts - Not too worried about this, I can fabricate if needed.
2) water pump exits on the wrong side - sort of a headache. Can I use my old water pump, or do I need to have my lower radiator hose mount relocated? It's a new aluminum radiator, so don't want to scrap it.

Anymore knowledge is great. I can do paint and body all day long, but am STILL an idiot when it comes to engines.

 

[Dako]

Pretty sure engine mount 'ears' on the block are the same. As long as you have the Poly brackets that tie it to the K-frame, it should be a straight bolt-in.

Have you matched up pumps? I won't say they are not interchangable, but I believe the timing covers are interchangable. There would be one 'unused' bolt hole in the Poly's cover. This would enable you to use a Poly water pump (dumping on the correct side for your radiator). Take a look at the below link for some details. It is a reverse comaparison, but you still get the same info. Hope this helps some.

http://www.1962to1965mopar.ornocar.com/poly318_1.html

 

[440roadrunner]

BALANCE

Depending whether this is an LA or Magnum, You can get a 360 balanced flexplate from BM, because (example) a 360 LA normally has weights welded to the torque converter. The prober BM flexplate makes up for these weights, IE you can then use a "neutral" balance converter

PUMP. I would do whatever it takes to stay with the 360 pump, because your pulleys, etc for the 360 follow suit, and the timing marks will be accessible. Heck, I'm just using a big lower hose that crosses over, "lays" in the front of the K memeber

CONVERTER

I'm pretty sure the pilot for the TQ is smaller than the modern engines. There ARE aftermarket bushing rings, or you can make one if you have a lathe. I don't recall the dimensions. It's a simple bushing ring.

 

[69Bee]

BALANCE

Depending whether this is an LA or Magnum, You can get a 360 balanced flexplate from BM, because (example) a 360 LA normally has weights welded to the torque converter. The prober BM flexplate makes up for these weights, IE you can then use a "neutral" balance converter

PUMP. I would do whatever it takes to stay with the 360 pump, because your pulleys, etc for the 360 follow suit, and the timing marks will be accessible. Heck, I'm just using a big lower hose that crosses over, "lays" in the front of the K memeber

CONVERTER

I'm pretty sure the pilot for the TQ is smaller than the modern engines. There ARE aftermarket bushing rings, or you can make one if you have a lathe. I don't recall the dimensions. It's a simple bushing ring.

The adapter rings seem to be discontinuesd. Also, you are fighting an internal converter issue. Prior to 68, if memory servers, the internal are different from the late style converters. I did the same with a 6-225 in a van. I put a 63 slant-6 into a 73 van attached to a 73 trans. I had to have a late style converter opened up, and put the early internals inside, then re-welded, and it worked great. Try to find a custom converter shop that can do the work, and it will be a cinch.

 

[66 coronet]

My cousin did this swap a couple of years ago, Used the 65 pushbutton transmission with a 73 360 engine. He got a flex plate with the balance weights from summitt, don't look in the catalog its not there he called them and they fixed him up.

 

[mgriffith]

Cool. Thanks. It's starting to sound a little simpler than I was making it out to be. It's just a big investment, so I guess I was getting nervous.

Keep the advice, tips, and life stories coming though. As originally stated, I'm an idiot when it comes to engines.

 

[mgriffith]

I know it has been a while since I posted this topic, but I have finally pulled the engine and started on the swap. I'll be sending the transmission off for a build this week. I ordered the B&M weighted flex plate this morning. Anything else I will need to get the tranny and engine mated up and back in the car?

 

[RustyRatRod]

What are you gonna do with the poly? Can I have it?

 

[pistol_grip_polara]

The motor mounts from the poly will work. on the drivers side, the ears will be backwards. If i remember correctly the poly has 1 bolt in front and 2 in rear, while the 360 has 2 in front and 1 in rear. I bolted it in place, welded a small piece of strap, drilled a hole, and works perfectly. Motor sits where it needs to, and hedders even cleared.

Havent dealt with the torque converter issue, im running a 4-speed. However, I have heard from a couple of guys the balanced flexplate from summit is about the easiest.

 

[kb67mopar]

If that timing cover from the poly doesn't pan out a 273 or 318 from the later 60's should also be a swap if you don't feel like playing with the radiator. Otherwise an even cheaper option is to just buy an aftermarket radiator with them on the proper sides. I have seen some inexpensive aluminum radiators out there for $100 to $150 (Northern Radiator).

I also recall an issue with the timing marks being in a different location on the newer 360's vs the old timing covers...so you will have to look into that, I can't recall how that worked but i think they were on different sides of the cover making the old marks useless for the later 360 engine.

 

[pistol_grip_polara]

not sure about coronet bolt locations, but I bolted in a radiator from a 72 dart with a 318 that i parted out. Bolted into factory holes on my 64 polara, and the hoses that i got from the parts store, just asked for some for a 72 dart... fit together like it was made to go in there.

 

[kb67mopar]

not sure about coronet bolt locations, but I bolted in a radiator from a 72 dart with a 318 that i parted out. Bolted into factory holes on my 64 polara, and the hoses that i got from the parts store, just asked for some for a 72 dart... fit together like it was made to go in there.

You may be right with this one. The 67 coronet I am parting has a radiator that the prev owner claims came from a Dart...mounting holes are the same.

 

[Powerflite]

The motor mounts from the poly will work. on the drivers side, the ears will be backwards. If i remember correctly the poly has 1 bolt in front and 2 in rear, while the 360 has 2 in front and 1 in rear. I bolted it in place, welded a small piece of strap, drilled a hole, and works perfectly. Motor sits where it needs to, and hedders even cleared.

Havent dealt with the torque converter issue, im running a 4-speed. However, I have heard from a couple of guys the balanced flexplate from summit is about the easiest.

Could you elaborate about your strap and hole for the motor mounts? I have a 277 poly in a '56 Plymouth and I found the mounts are much wider apart (mount to mount distance) than the small block mounts. My poly mounts are the same as the 392 hemi mounts so I just dropped one of those in instead. But the small block mounts are closer together. I'm just trying to figure out if the 318 poly mounts were moved inward at some point, or if you did something with your strap to move them out.

 

[pistol_grip_polara]

i welded it inline.. i will take a pic tonight. I have the motor out and can snap a quick one when i get home.

It was fairly simple.. lots of people told me it wouldn't fit and would need to buy special mounts....

 

[pistol_grip_polara]

totally spaced getting pics... i will try and do it in the next day or 2, got too excited about finding a new jet boat... sorry powerflite

 

[mgriffith]

Ok, I've got this thing close to ready to put in. One problem I've run into is that the water pump pulley doesn;t fit. it isn't deep enough to lineup with the rear groove on the crank pulley. The engine has a long neck water pump on it. Is my problem due to the pulley simply being wrong for the engine, or was it intended for a short neck pump? If so, did they even produce short neck pumps for this engine?
Anybody got the correct pulley???

 

[mgriffith]

More frustrations. The brand new, aluminum high rise intake that my engine came with is not going to clear my hood. Too damn tall. Sucks, it looks so good sitting up there.

 

[RustyRatRod]

Hood scoop.

 

[kb67mopar]

probably going to have to research that pully a little bit. I am not even sure which setup you are running. Are you trying to put the poly perfipherals on the 360? Are you putting an early style LA cover and pump on to correct for the radiator? You will have to give some details and then see what fits. There are a number of different pulley's out there.

 

[mgriffith]

Rusty, gimme some ideas of a good scoop. My car is more a low down cruiser cruiser than muscle car; so it has to fit the look corectly. Otherwise I'll have to sell/trade the intake for something lower rise.
KB67, I am using all 360 pulleys, brackets, etc on the engine. I think I found the correct pulley from Bouchillon, but its pretty pricey and with nothing working out as expected on this swap, funds are being sucked up fast! But anyways, I think the pulley that came w the engine was just the wrong one for the long neck water pump.