Need input...rebuild 318 poly or build 360LA

[threewood]

This has probably been beat to death so if anyone has a link or two I would appreciate it.

1962 Ply Belv 4 door with original 318 2 bbl and pushbutton torqueflite, 8 3/4 741 rear end.

I'm pretty sure the valve seals need replacing as the car is smoking. I haven't ran a leakdown or compression test but figure the engine is due for a refreshing. This will never be a race car but I would like a bit more power for the street. I was thinking about getting the heads done with new valves and hardware, block bored .030 to .060, new bushings the whole 9 yards.

I like the poly design and it is original to the car but the rub is that for basic upgrades the price is much more than a 360 la. Heck, 4 bbl intake and headers alone put me at $1500. Simpler but more expensive.

Now the 360 would be neat. Intakes, headers, and replacement parts are less expensive. I have seen complete motors in the $500 to $700 range. What is needed for the swap? I want to stay with a carb. Engine mounts the same? Flywheel? Torque converter for the 360 but hook it to an early 727 with different input splines?

What to do, what to do?

 

[69Bee]

The 360 would be better in the long run (40 extra inches), but you will need the later 727/904 for an easier install. The late engine will not easily (cheaply) adapt to the early tranny. A floor shifter will make the adaption easier too. As far as I know, the engine mounts from the poly should also work on the 360, but you might need to shim one bolt with washers to fill a gap between the mount and mounting ear.

It isn't too hard to find a 360 and tranny for a few hundred, but expect to spend up to $2500 to $3000 to rebuild it. This would be if you do everything, and that is the best time to do it. I would swap the rear end for a later "non-tapered" axle, as they are easier to work on. You also will need to modify the driveshaft more than likely, but is easy enough at any driveline shop like Tucson Driveline.

 

[threewood]

The 360 would be better in the long run (40 extra inches), but you will need the later 727/904 for an easier install. The late engine will not easily (cheaply) adapt to the early tranny. A floor shifter will make the adaption easier too. As far as I know, the engine mounts from the poly should also work on the 360, but you might need to shim one bolt with washers to fill a gap between the mount and mounting ear.

It isn't too hard to find a 360 and tranny for a few hundred, but expect to spend up to $2500 to $3000 to rebuild it. This would be if you do everything, and that is the best time to do it. I would swap the rear end for a later "non-tapered" axle, as they are easier to work on. You also will need to modify the driveshaft more than likely, but is easy enough at any driveline shop like Tucson Driveline.

On my transmission, is it possible to swap the input shaft for a later one? I don't know why but I like the tapered axles. Unique nowadays I guess. Good info on the motor mounts, could probably fab a spacer. Hmm, I guess rebuilding the poly would be less of a headache. How well do the stock poly exhaust manifolds flow? If I were to get the 4 bbl intake, mild cam, 500ish carb, and run dual exhaust would the restriction be too much?

 

[mopar 3 B]

Run 2 1/4 or 2 1/2" doule exhaust and it should run ok. Was running the 290 HP setup on a 66 poly without any problems with exhaust. Check the casting date on your poly as I believe 62 and older blocks where different then 63-66. The newer blocks used the same transmission bolt pattern as LA blocks. The tans input shaft will swap. Use the proper converter for the engine. Would be advisable to replace the front pump when doing the input shaft swap. There are poly sites with more accurate info just google poly block.

 

[66 coronet]

keep it original stay with the poly all the poly engines from 62 to 66 are the same, you will be suprised how good they will run. Clean up the ports and mill the heads .060" A mild cam pull the flapper out of the right side exhaust manifold and put duel exhaust stay with a two barrel to keep it looking stock, maybe a two barrel of a 360. I had so much fun with mine I had to spring for a four barrel and some headers.

 

[hemi#1]

stay with the poly you can take that poly to a 396c.u. stroker on pump gas pushing 450+ h.p. that's what I want to do with my 65 satellite parts are out there I found a 3 duce manifold for mine but haven't gone stroker yet. I want to drive and show it when I'm done with it TX. weather I can do almost year round. no sitting in a garage or trailer queen.

 

[SublimeSixpack]

I'd stay with the Poly.

 

[Dako]

The short of it...you can build your Poly to an impressive 'seat-of-the-pants' attention getter for less.

Yes, you can put a used, running, 360 (and its trans) in place of the Poly for less than what it costs to rebuild the current motor. But add to it the costs of any 'do-dads' or a rebuild of the used 360 and you quickly exceed the Poly mod/ rebuild costs. Mods needed (later trans, linkage change, exhaust...and the list will grow) to make the 360 work, can nickel and dime you.

Use the search option on this site and contact Gary Pavlovich. He is a member. He has done extensive 'experimenting' with these motors and can walk you through several options to achieve a build that fits your budget...no charge, he just has a passion for these motors and enjoys helping others. I priced out parts between him, Eggy, and the machine shop I used. He was the best deal, and he not only answered any technical questions, but talked with the machine shop I used to ensure they were working the ports properly. We talked via phone while I assembled the motor and he followed up with email & phone calls later to ensre I was satisfied and all was working. I don't think you will be disappointed. I know I wasn't!

 

[threewood]

Stuck with the 318A and I am happy I did. Special thanks to GRC Performance and Gary Pavlovich for getting it done! It was already at .030" over and they took it to .040" over to clean up some scuffing. Some head work, new exhaust valves, springs, keepers and the rocker arm assembly rebuilt and spec'd to a true 1to5. Schneider .450 at 264* cam. Eagle I beam rods, polished crank with Egge 9.0 to 1 pistons, block decked and heads milled. Stock 4 bbl intake port matched to heads, crossover blocked off, plenum opended up for new Edelbrock 600cfm. TTI headers out through dual 2 1/2" exhaust and Dynomax Ultra Flow mufflers. Timing set at 17* initial / 33* total

 

[Schober Motorsports]

Did you have your original cam reground or did you buy new? I have had a hard time finding people who cuts cams for this motor.

Also looks awesome! Well done.

 

[threewood]

Did you have your original cam reground or did you buy new? I have had a hard time finding people who cuts cams for this motor.

Also looks awesome! Well done.

New cam from Schneider Racing Cams, solid tappet. Their website says they are out of new ones until further notice so it might be worth a call to see when they will be available again. I really like mine, power band from 2500 to 5500. Got some lumpiness but very streetable.

 

[miller]

My eye! My eye!!!

 

[Dako]

Schneider reground my original. No complaints, and it was half price of a new one.

Looks great! I have heard all kinds of comments on mine at shows:
"What engine is that?"
"Is that a big block?"
"Ha! It says 318 on the placard."
"Where do you find parts for a Poly?"
"Why keep the Poly?"
"That does NOT sound like a small block."
"What is it, really."

Have fun my friend!

 

[Homstead]

That looks awesome! Glad you stuck to the poly. It just looks at home in that car!

 

[KarNut46]

Poly to LA conversion. The bellhousing mount on the 62 up poly 318 is same as later LA engines as well as the crank flange. Breakover year is 62, 61 and older had same bell and crank flange as the older gen 1 hemis and polys. Changing input shafts: remember reading an article in MA about that some time back (had the same problem w/ my 65 trans at the time) and it's a bit more complicated than one would think. 66 up trans input shaft different than 65 and older. 360 engines are externally balanced and have a counterweight welded to the torque converter. You could remove the weight from a 360 converter and have it welded to your 62 converter. Would have to be precisely located tho. Remember that accessories on the 360 will bolt on differently than they do on your poly engine. Engine mounts same, or very similar. Slight mod necessary. 318 poly ex manifolds quite restrictive. I might be able to locate the info on input shaft swap from MA if you really want it.

 

[KENTON]

My eye! My eye!!!

What happened to your eye ? Do we need to cal 911 for you ?

P.S. keep your poly.

 

[miller]

Naw...only got one eye! Almost got blinded by all that shiny brightness.

 

[dvw]

I can see keeping the Poly for the "old look". However from a power standpoint a junkyard 5.9 magnum with a cam (reuse stock roller lifters) and a 4 barrel intake will exceed the power of 95% of the Poly builds for far less dollars. Your engine looks great by the way.
Doug

 

[Blackheart]

stay with the poly you can take that poly to a 396c.u. stroker on pump gas pushing 450+ h.p. that's what I want to do with my 65 satellite parts are out there I found a 3 duce manifold for mine but haven't gone stroker yet. I want to drive and show it when I'm done with it TX. weather I can do almost year round. no sitting in a garage or trailer queen.

My 396 CI Poly