Posted By: AtomicDog
1963 Poly 318 - will later model 727 bolt-up to it? - 08/20/13 11:09 PM
I have a friend that is using a 1963 poly 318. Does anyone know if any small block 727 transmission from the mid 1970's will bolt-up to it and operate?
Posted By: therocks
Re: 1963 Poly 318 - will later model 727 bolt-up to it? - 08/21/13 12:03 AM
The trans will bolt up but convertors are different.I think you can use the late convertor on the poly but not the poly on the later crank.The difference is the register diamiater on the crank.We put a LA in the 66 Charger after the poly locked up.One bolt wont line up IIRC but it works.You can not swap convertors from late to new either.I believe 66 was the last year for different splines on the convertor.Rocky
Posted By: Supercuda
Re: 1963 Poly 318 - will later model 727 bolt-up to it? - 08/21/13 12:36 AM
early converter snout is smaller than the later, so you can't swap late to early, but you can have a converter made to fit the later trans and the early crank. Years ago I got a quote from a local trans shop that was reasonable and they knew what I was talking about, so call around.
Posted By: Andrewh
Re: 1963 Poly 318 - will later model 727 bolt-up to it? - 08/21/13 02:39 AM
there must be something that can be done on the crank as well.
the old trick to get a forged crank was to steal one out of a poly and rebalance for a 340.
Posted By: slantzilla
Re: 1963 Poly 318 - will later model 727 bolt-up to it? - 08/21/13 07:48 AM
Most any converter company will make a small pilot converter.
Edge or Continental used to do them for less than $200.
Posted By: dogdays
Re: 1963 Poly 318 - will later model 727 bolt-up to it? - 08/21/13 07:54 AM
I am putting a 86 318 in my '64Dog. I know for a fact that the bolt below the driver side dowel is in a different location vertically. You should be able to drill from the newer trans into the Poly flange and install a 3/8 or 7/16 bolt.
As far as the torque converter nose I'll have to check if there's enough material to bore it out.
Keep in mind that 340s were usually mated to 4-speeds back in the day, at least among those who may have swapped in a forged 318 crank.
R.
Posted By: slantzilla
Re: 1963 Poly 318 - will later model 727 bolt-up to it? - 08/21/13 09:54 AM
When you mate a post '67 motor to a pre '68 trans you can get a spacer ring for the crank register that will let it accept the small converter pilot.
Posted By: dogdays
Re: 1963 Poly 318 - will later model 727 bolt-up to it? - 08/21/13 05:41 PM
I am using the original NP420 so I personally care nothing for the torque converter ring problem. I said I'd check it out for the OP, who is using an automatic transmission.
R.
Posted By: John_Kunkel
Re: 1963 Poly 318 - will later model 727 bolt-up to it? - 08/21/13 06:17 PM
The converter hub diameter difference only relates to the 904, all 727 converter hubs are the same diameter.
All '62-later poly cranks had the large register, only the early /6 and 273 had the small register.
The only problem encountered when mating a later 727 to a poly is the bellhousing bolt pattern, there is one bolt hole that won't align.
Posted By: dogdays
Re: 1963 Poly 318 - will later model 727 bolt-up to it? - 08/21/13 07:14 PM
Thanks, you answered my question, though I didn't ask it!
So the late pilot bearing will work in my Poly crank, if I ever decide to rebuild it.
Also, the hole that doesn't line up is drivers side below the dowel, with enough material to be able to drill and tap a hole that will work.
R.
