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241 HEMI to 904 questions

Discussion in 'The Hokey Ass Message Board' started by 29EHV8, Mar 31, 2009.

  1. Eh guys, weve put a lil Red Ram in a T RPU and well we didn't have enough room to run a stick in it so we switched it to a 904. Well were having troubles finding a flexplate to work. Also wondering about the starter, looks like we can cut the block and bolt a starter to the trans. Not a big deal, just want to see if anyone else out there has run this setup and what you did. Before we go out and get a 727 and try that.

  2. d2_willys
    Joined: Sep 8, 2007
    Posts: 4,165

    from Kansas

    would check the hemi tech section for previous posts. Wouldn't cut a block for a mil!
  3. swifty
    Joined: Dec 25, 2005
    Posts: 1,829


    Guy I know runs a 904 behind the 318 poly (A block) in his Buick custom and does lots of miles. He had to cut the block to do it same as you would. I think I'd run the 2 support bars from the block to the bottom of the trans bell housing just to be sure.

  4. llonning
    Joined: Nov 17, 2007
    Posts: 679


    The 904 is a 6 cyl and SBM trans, 727 is HD 6 cyl, HD SBM, and BBM trans. The bolt patterns are different of course. I am assuming you are using the SBM pattern. No difference in bolt up. It would take the same to bolt up either one. I AM NOT a Hemi expert though, by any stretch. Like d2 willys said check the Hemi tech, loads of good info there.

  5. 73RR
    Joined: Jan 29, 2007
    Posts: 6,586


    Be very careful !!!
    'Cutting' the block to clear the starter will likely include the removal of the locating dowel. Use a 727 and put up with the additional internal drag.
    As for the flexplate, what was provided with your adapter package? Or, are you saying that you simply bolted the trans to the block? You know of course that this will not work well, if at all, if you do not have the alignment dowels in position. Additionally, the block adapter is required to correct the difference in the distance that the crank flange extends compared to the late engine that the trans came from. The thickness of the block adapter and the thickness of the crank flange adapter must be designed as a working pair to maintain the proper dimensions. The crank flange adapter must also provide some means by which to register the flexplate. The Torqueflight front shaft seal and front pump assembly are very sensitive to parallel mis-alignment, 0.007" TIR is about the max recommended.
    Without an adapter, there is not only insufficient space for the converter, there is no way to drive the converter.

  6. Hot Heads ( a Hemi site) has the adapter to put the 904 behind the baby Hemi. They have the spcer for the trans and the flexplate.

  7. ...As does Wilcap...
  8. hemipickup
    Joined: Apr 18, 2008
    Posts: 16

    from australia

    i have done this conversion, you have to grind quite a bit of material off the back of the block to clear starter, almost down to dowel, left 1/16th inch around dowel, also had to grind a lot off starter motor, also that was mini starter, it does fit but very tight. better with 727.
  9. What did you use for a flexplate? Any other insight/ advice?

    I'm lookin into this for a good buddy. He got the trans adapter from a knowledgable old guy, its really nicely made. But didn't have a flexplate as he got a 4 speed setup with the HEMI. We couldn't fit it into the car as there was no room for 3 pedals:mad: so gotta run fluid drive instead:rolleyes:

    Thanks for all the info and some of the advice:D I'll look into the HEMI tech too.

  10. George
    Joined: Jan 1, 2005
    Posts: 7,442


    The 8 bolt 426 Hemi flex plate should work.

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