727 W/ 904 internals

[GTX JOHN]

727 come in both small block and big block bolt patterns.......easiest way to ID
on shelf is small block is above starter the block bolt hole and starter bolt hole are directly above each other and big block starter hole is at 45 degree angle
from block bolt. Also if you measure two top bell housing holes there is a inch and a quarter width difference between big and small blocks. 904 is physically
much smaller and quite a bit shorter as well as imput shaft is smaller. There are currently available adaptor housings to mate a big block to a 904 and that
is what I use on my Bracket Cars. I do not believe that they are accepted for
stock or SS and I wish they were as it would save mucho money.

This should be way more information than anybody probably wanted......Sorry

[Todd Boyer]

Chrysler made 727s for both big blocks and small blocks but built 904s for small blocks only, and I think Mark runs a big block.

[Mark Maez]

Yeah, were running a 383 W/ a light weight 727 a really super trick piece by Automatic Performance Transmissions. I dont think I could get a tenth with a 904 but would still try it, I would like to build the unit myself but it was still unclear if the whole geartrain is used or just a few components. My bracket car did'nt go faster with a 904 but it did pick up MPH.

[Knocky]

Originally Posted by GTX JOHN

727 come in both small block and big block bolt patterns.......easiest way to ID
on shelf is small block is above starter the block bolt hole and starter bolt hole are directly above each other and big block starter hole is at 45 degree angle
from block bolt. Also if you measure two top bell housing holes there is a inch and a quarter width difference between big and small blocks. 904 is physically
much smaller and quite a bit shorter as well as imput shaft is smaller. There are currently available adaptor housings to mate a big block to a 904 and that
is what I use on my Bracket Cars. I do not believe that they are accepted for
stock or SS and I wish they were as it would save mucho money.

This should be way more information than anybody probably wanted......Sorry

Not at all John! Love those details. Good to hear those positive results. I'm investing in a 727/904 currently being built!
MWNorris

[Phillip marvetz]

Where do you get an adapter John?

[Myron Piatek]

Originally Posted by Phillip marvetz

Where do you get an adapter John?

If I may........J. W. Transmissions in Rockledge, FL makes the "Ultrabell" as one option. It's basically an SFI certified flywheel shield as well as an adapter available in quite a few configurations.
I couldn't help but wonder if NHRA could be petitioned for its acceptance in Stock and/or SS based on its safety qualities, as long as a corporate trans is used. (If it hasn't been tried already.) GM and Ford appear to have the luxury of interchangability of their big and small transmissions between big & small blocks. It would save some money over 727 cases with 904 internals.

[bdixon]

Been there done that!!!!!!!!!!! First asked div. passed me on to national both said not yet ...wanted to use 904 with ultra bell for stock in my big block combo,, I do think if more people would call and ask it would help,, it would be a safety issue also the ultra bell is sfi approved..bryan d stk5010

[Mark Maez]

The rules regarding the case being OEM would have to be changed I dont think that should happen in stock, maybe Superstock.

[GTX JOHN]

When we bought the White 73 Roadrunner 6 or 7 years ago it

had the 904 with adapter mating it to the 440. It had been raced

for several years in stock with it and apparently never had a problem.

I did not ask anyone or say anything about it ................ I just removed it!

Phillip: I will go over to shop tomorrow and let you know

who manufactured the unit. It has the trans bell housing machined

off and replaced with a bolt on bell housing with big bolt pattern

adapter and requires no spacers or special flexplate but uses

904 converter of course.

[Mark Maez]

Originally Posted by Myron Piatek

If I may........J. W. Transmissions in Rockledge, FL makes the "Ultrabell" as one option. It's basically an SFI certified flywheel shield as well as an adapter available in quite a few configurations.
I couldn't help but wonder if NHRA could be petitioned for its acceptance in Stock and/or SS based on its safety qualities, as long as a corporate trans is used. (If it hasn't been tried already.) GM and Ford appear to have the luxury of interchangability of their big and small transmissions between big & small blocks. It would save some money over 727 cases with 904 internals.

Lighter torque converter also, how do you petition for something like that?