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318LA / 318 Poly / 904 transmission?

Discussion in 'The Hokey Ass Message Board' started by Revhead, Jun 22, 2010.

  1. Revhead
    Joined: Mar 19, 2001
    Posts: 3,027

    Revhead
    Member
    from Dallas, TX

    So I working on updating the drivetrain in my '55 dodge and Here's what I have picked up so far...

    318LA and 904 trans out of a running and driving '87 pickup.
    NOS 1960 318A poly block and pistons
    '58 318A poly heads

    and soon, a '66 318A (poly) complete motor.

    Now I seached the hamb and rest of the internet and found that the 727 from the 318LA should bolt right up to a post '62 318A. The differences between the early and late 318A bellhousing pattern was mentioned to be very minor and only one bolt and/or dowel pin location.

    I held up the sheet metal torque converter cover from the 904 to my early 318A bellhousing and it doesn't look anywhere close to matching up... even a little.

    I hope I didn't just fall into the trap of believeing anything written on the internet, but there seems to be quite a few people who have mated up a later trans to the earlier polys.

    I assume that the 904 had the same bellhousing pattern as the SB 727, am I right?

    Is the early 318 poly bellhousing that much different from the latr one and not just a bolt or two?
     
  2. 73RR
    Joined: Jan 29, 2007
    Posts: 7,299

    73RR
    Member

    The pre-62 A-series (277-303-313-318-326) have the same bellhousing bolt pattern as the Hemi series. There are four bolts that are common from early to late but dowels and other bolts are off. If you want a late TF and an early A engine then buy/use a Hemi to TF adapter.
    The v-8 904 (small block only) has the same bolt pattern as the small block 727, but there is a /6 904 that is different. Also, the starter on a 904 sits about ½" higher than on the 727 and is an issue for Hemi swaps.

    .
     
  3. Revhead
    Joined: Mar 19, 2001
    Posts: 3,027

    Revhead
    Member
    from Dallas, TX

    ok, well My budget is limited so a trans adapter is not really an option, but If I understand right the '66 318 poly and my 904 should bolt right up correct? will the started be a problem with this combination?Do I use the same flexplate from the 318LA?
     
  4. George
    Joined: Jan 1, 2005
    Posts: 7,802

    George
    Member

    The '66 & 904 should bolt right up & flex plate should too. On a hemi there is a clearance problem with the starter, not sure about the A block.
     
  5. flatoz
    Joined: May 11, 2003
    Posts: 3,237

    flatoz
    Member

    pm swifty as he has done this recently he can tell you what was needed, I know there was some massaging of the block? to get the starter to fit. send him a pm he probably even has photos.
     
  6. Abomination
    Joined: Oct 5, 2006
    Posts: 6,774

    Abomination
    Member

    He WOULD keep porn like that around... ;)

    ~Jason

     
  7. Hippy Dave
    Joined: Jul 23, 2013
    Posts: 1

    Hippy Dave
    Member
    from Australia

    Hi Flatoz
    I am fell member from Oz based in Sydney and I am having problems with my 1964 318A bolt up to 904 transmission. Yes there is a corner on the block that fouls the starter installation.

    I would like to make contact with the guy that may have made this work before.
    Searching the site there are several members with "swifty" in the name. Is it the member in melbourne?
    regards
    Dave
     
  8. George
    Joined: Jan 1, 2005
    Posts: 7,802

    George
    Member

    Might have to get a small block 727
     
  9. flatoz
    Joined: May 11, 2003
    Posts: 3,237

    flatoz
    Member

    Dave Pm him his name is just plain 'swifty' the motors in a 32 coupe
     
  10. The LA should bolt up to your 904 just fine. The poly is not going to bolt up without an adapter.
    Unless of course like @73RR said you got a 6 cylinder 904 transmission.

    Most people don't want a 904 so if you have the wrong transmission they are plentiful and fairly cheap.
     
  11. Big Swede
    Joined: Sep 21, 2015
    Posts: 48

    Big Swede
    Member

    Found this during a search, were you ever successful in your mating of the poly and your 904? I'm doing something similar in my '55 Savoy. Only problem I'm having is where the starter bolts up and that seems to be an easy fix. All but one (the top center bolt) of the bolt holes and dowels lined up perfect. My poly is a 63 model and the trans is out of a '72 if that makes a difference.


    Sent from my iPhone using The H.A.M.B. mobile app
     
  12. 73RR
    Joined: Jan 29, 2007
    Posts: 7,299

    73RR
    Member

    The 63 Poly block has the exact same bolt pattern as the LA so you are good to go.

    .
     
    Big Swede likes this.
  13. Big Swede
    Joined: Sep 21, 2015
    Posts: 48

    Big Swede
    Member

    Thanks. Time for some clearance-ing on that tab to fit the starter.


    Sent from my iPhone using The H.A.M.B. mobile app
     
  14. gene-koning
    Joined: Oct 28, 2016
    Posts: 4,556

    gene-koning
    Member

    Some of the issue may be that a small block (or any) 727 uses a different flex plate then a 904. The 904 flex plate is smaller, as is the torque converter. You have to use a 904 converter and flex plate with the 904 trans. All of the 904 flex plates I've seen are for 6 bolt crank flanges, that's not saying someone doesn't make an 8 bolt 904 flex plate, it means I've never seen one.

    A 904 trans case is either a slant 6 bell pattern, or the small block V8 bell pattern. You have to use the 904's V8 trans case to bolt to a V8 motor. The starter notch in the bell is higher on the trans for the slant 6 bell then it is on the small block V8 bell. You may have to grind clearance for the starter to bolt up when the 904 V8 trans is used with the Poly motor, and the older poly motors may require an adapter.

    The 904 started life as a slant 6 transmission only. Then around 68 or so, Chrysler added an extra clutch to the forward clutch pack and changed the bell to add it to the 273 and 318 in the A body cars. Later it was beefed up more to put behind the 340 and the 360 motors. The smaller rotating mass then a 727 can improve standing start acceleration and make faster shifts. The 904 can be built up to withstand some pretty high power. There have been racing teams that have cut off the bell and added a big block bell and have successfully ran the 904 behind big block Mopar motors, but I'm not sure how that was accomplished. Gene
     
  15. Big Swede
    Joined: Sep 21, 2015
    Posts: 48

    Big Swede
    Member

    Thanks Gene. I have a small block 904. A quick search on the interwebs shows 8 bolt flex plates for 727/904 applications.


    Sent from my iPhone using The H.A.M.B. mobile app
     

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