Rebuild Poly 318 or install LA 318 ?

[65GUS]

hi all. ive got a 1965 fury 3, with a worn out poly 318. it was dropping oil pressure the last 2 years , and now its been determined that the cam bearings are totally shot. my question is, do i do a total rebuild on the poly, it will be spendy ( parts wise ) or i may have access to a late 60's ( 67-69) LA 318, which could be freshened up before the re-install. the fury only gets driven about 3000 miles a year so its hard to justify a total rebuild with upgraded parts. i know the 65 fury has a 1 year only LH motor mount, what all would need to be modified to install a LA motor in place of the poly ?? im figuring at least the exhaust pipes to exhaust manifolds. are the inlets on the water pump on the same side ? maybe some body has a good or rebuilt 318 poly to fit my 1965 ?? Im out here in Oregon, so east coast motors probably $$$ to ship, anyways, any info on a motor swap or a good used poly 318 or a good local Oregon Mopar engine builder is all appreciated, thanks

 

[MoPar~Man]

What transmission do you have?

My '67 Canadian Monaco came with a 318 poly, in 1987 I replaced it with a 318- LA. It bolted right up to the 727 transmission and no problems with motor mounts. Your '65 Fury has a different frame mounting setup but on the engine side the poly vs LA should be identical. I would recommend you find a complete LA engine because nothing can be swapped from the poly. I bought a re-man LA318 and had to find intake, exhaust, oil pan, valve covers, I think also timing chain cover. Also throttle bracket. Not sure about the distributor.

 

[Darter6]

I put a 1970 LA 318 in my 63 Belvedere replacing the Poly. I used the 70 904 transmission.
I understand and may be a rumor that the Poly torqueflites only have one bolt hole that is different but bolts right up without using that bolt.
Great looking 65 !!!

 

[CBODY67]

The Poly A engines fathered the LA motors. Should be same bellhousing bolt pattern, even the same timing chain, IIRC. Uncle Tony has a YT video on the history. A title like "The Engine Chrysler Should have Developed", or similar. Plus a few others.

If it were mine, I'd rebuild the Poly with OEM-spec parts, not looking for "upgrade" parts. Maybe a roller timing chain, though.

If going to an LA, why not up the ante and go for a 360? But you'd need a balance-weight torque converter. But the weight kit used to be available from Mopar Perf/the old Direct Connection parts group.

CBODY67

 

[Ripinator]

hi all. ive got a 1965 fury 3, with a worn out poly 318. it was dropping oil pressure the last 2 years , and now its been determined that the cam bearings are totally shot. my question is, do i do a total rebuild on the poly, it will be spendy ( parts wise ) or i may have access to a late 60's ( 67-69) LA 318, which could be freshened up before the re-install. the fury only gets driven about 3000 miles a year so its hard to justify a total rebuild with upgraded parts. i know the 65 fury has a 1 year only LH motor mount, what all would need to be modified to install a LA motor in place of the poly ?? im figuring at least the exhaust pipes to exhaust manifolds. are the inlets on the water pump on the same side ? maybe some body has a good or rebuilt 318 poly to fit my 1965 ?? Im out here in Oregon, so east coast motors probably $$$ to ship, anyways, any info on a motor swap or a good used poly 318 or a good local Oregon Mopar engine builder is all appreciated, thanks

View attachment 685718

View attachment 685719

I would rebuild the Poly. It is truly unique and it makes really good power if you set it up correctly (upgraded cam and either one or two four barrel carburetors. Here is an article describing what is possible at the extreme. However, I would just do the cam, a four barrel carb and a set of headers:

https://www.motortrend.com/how-to/mopp-0110-how-to-give-a-318-poly-engine-more-power/

 

[Davea Lux]

You have a nice '65. I would keep it original. You will also start with about 30 more horsepower as apposed to an LA 318.

Dave

 

[MoPar~Man]

Look here for A - LA interchange:

Poly 318 Polyspherical Parts Interchange - Poly318.com

Poly 318 parts interchangeable polyspherical 277, 301, 303, 313, 326 interchange LA 273, 318, 340, 360, Magnum 5.2 5.9 Plymouth Dodge Chrysler Mopar engines.

poly318.com

Or just look at that site in general to know what's possible for your poly. It would be great if that site had a simple section or page that just told you what parts are still relatively available today and which ones aren't, something to help you decide if rebuilding your A block is a viable option.

 

[carrman]

It IS a nice car, I've had the privilege of being in a few shows with him.

 

[carrman]

Your car, sir.

 

[Darter6]

Screamin' Poly in my buddy's 64 Dodge station wagon .
Stroked and poked to 390 CID. If you didn't open the hood you would swear it's a 440.
I too believe use what you got. Only reason I went with the LA as it and the 904 were free.

 

[65GUS]

thanks to all replies.im thinking rebuild the poly also, as i know it will drop right back into place with no mods. if the motor checks out ok at the machine shop ill go that way, but if not then will probably look to a early LA 318. i know of 1 here in town that i could buy at a reasonable price, i think. remembering a used take out motor is an unknown product. ive been in touch with Gary P. in San Diego, and want to use his upgraded mild performance parts. thanks for pics there carrman. and Dave Lux, i always value your insight .BUT if anyone ( west coast) has a good used poly for a 1965, give me a holler, thanks to all. GUS