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55 Chevy V-8 install help!!!!!!!!

Discussion in 'The Hokey Ass Message Board' started by Leadsled51, May 27, 2006.

  1. Leadsled51
    Joined: Dec 21, 2001
    Posts: 333

    Leadsled51
    Member

    I am putting a 350 in a 55 chevy for someone and he wanted to keep the powerglide in it. It is an original 55 tranny. It had a 6cyl in it. Is the adapter that goes between the engine and tranny different? I thought that all the early chevy trannys bolted up to any v-8? I didn't know that the bolt patterns were different. Or am I overlooking something? Help
     
  2. propwash
    Joined: Jul 25, 2005
    Posts: 3,858

    propwash
    Member
    from Las Vegas

    bellhousing on a 55 p/glide should bolt right up to the V8...you'll need it to, as that is where the rear engine mounts are located. This swap has only been done about a gazillion times in the past fifty years...no adaptors needed. If the 55 was a six, you'll need front motor mounts for the V8 and you really should move the radiator to behind the front radiator crossmember, or it won't cool properly - although the modern solve is a nice electric fan.

    "is four on the floor a double-date at the drive-in movie?"

    dj
     
  3. dchapmansr
    Joined: Oct 30, 2005
    Posts: 39

    dchapmansr
    Member
    from Katy, TX

    To the best of my knowledge the 6 cyl. bell in 55 was different than the v8 bell. You need a V8 trans for this swap. I don't think the splade trans mount surface on the back of the V8 engine started on 6 cylinder engines until 62. I know my 59 6 cyl has no way to mount a v8 trans with out some type of ataptor.
     
  4. jonski und29
    Joined: Oct 13, 2005
    Posts: 134

    jonski und29
    Member

    I mess alot with 55-57 chevy's, and if its got the original cast-iron powerglide, the factory v-8's had a thin adapter about 2-inches wide. powerglides came out before v8's, so the trans was designed for the longer 6. they needed a connecter for the short v8. I know thats the case with a '56
     

  5. squirrel
    Joined: Sep 23, 2004
    Posts: 47,100

    squirrel
    Member

    The 6 cyl pg is different from the V8 pg, the bellhousing is different, and if you try to just pull off the bellhousing you'll get a quick lesson in how the cast iron PG is put together...which you'll probably regret.

    bottom line, you need a different trans. You can't just use a 6 cyl PG with a V8 adapter ring, the starter hole is in the wrong place, etc.
     
  6. Why wouldn't the guy spring for a TH350 or a 700R4???

    Sam.
     
  7. Larry T
    Joined: Nov 24, 2004
    Posts: 7,660

    Larry T
    Member

    It would end up a better combination, but besides the transmission you'd have to have engine sidemounts and install a transmission crossmember. Not exactly a R&R.
    Larry T
     
  8. Actually, you can use the stock front mounts and then Danchuck sells an a-dapter kit to bolt to the belhousing bolts that uses the stock "ear" mounts. Then they also sell a kit that you can use the stock column shifter too.

    Sam.
     
  9. Leadsled51
    Joined: Dec 21, 2001
    Posts: 333

    Leadsled51
    Member

     
  10. Leadsled51
    Joined: Dec 21, 2001
    Posts: 333

    Leadsled51
    Member

    Sam, do you mean the adapter kit you mention above is for a TH350 or 400 trans?
     
  11. squirrel
    Joined: Sep 23, 2004
    Posts: 47,100

    squirrel
    Member

    yeah, the kit uses the trans to block bolts to mount "ears" that connect to the original style bellhousing area motor mounts. This lets you mount any modern trans, such as a th350 or 400 in the 55-57 cars using the stock front and rear motor mounts, instead of the modern side mounts.

    It's a kluge....and looks like crap....
     
  12. ... and they can bend easily if the bolts loosen up... and yea, I wouldn't mount one that way... but, if you're not wanting to mess with doing the side mounts and the tail shaft mount, it's an easy way out.

    Sam.
     
  13. propwash
    Joined: Jul 25, 2005
    Posts: 3,858

    propwash
    Member
    from Las Vegas

    I retract my "gazillion times" comment - I've actually done it twice, but do not recall a problem with the oem p/g bolting to a V8 swap...perhaps they were later trannies?

    dj
     
  14. squirrel
    Joined: Sep 23, 2004
    Posts: 47,100

    squirrel
    Member

    The 63-up 230/250/292 6 cyl will bolt up to a V8 tranny and vice-versa, but the old 235 is a different story.
     
  15. Model A Vette
    Joined: Mar 8, 2002
    Posts: 1,070

    Model A Vette
    Member

    As mentioned above the cast iron PG pre-dates the V8. To allow use of the same trans for a 55-57 V8 Chevy used a thin adapter (also mentioned above). The ears to mount the trans (in the bellhousing area) were on the trans NOT the thin adapter. I still have one of these thin adapters which I use to stand a V8 on end even if the crank is installed. Cars with stick trannies used different bells for V8 and straight 6 engines. These bells had the side ears to mount support the bellhousing/trans assemblies.
     
  16. Didn't they have that thin one... and a thick one on the manual transmissions? But the PG used the thin one and the integrated bell on the trans itself?

    Sam.
     
  17. Leadsled51
    Joined: Dec 21, 2001
    Posts: 333

    Leadsled51
    Member

    Ok, I am going to take some pics of the two different adapters that I have and maybe this will help clear things up. The guy I am doing this for, happened to have a reproduction assembly manual for 55. In the engine to transmission section, It actually listed two different part numbers for transmissions, one had a pic of a 6, and the other an 8. I think someone earlier stated there were two different trannys, and I am beginning to think they were right. Man this sucks, I thought this would be one of the easier jobs. Yea right.
     
  18. Model A Vette
    Joined: Mar 8, 2002
    Posts: 1,070

    Model A Vette
    Member

    There were two different bellhousings for 55-57 trans: one for the 6 cyl and another for the 8 cyl.
    It was cheaper for Chevrolet to make two bellhousings rather than one bellhousing and TWO adapters.
    It was cheaper to make one 6 cyl PG case and an adapter to mate it to the 8 cyl.
     
  19. squirrel
    Joined: Sep 23, 2004
    Posts: 47,100

    squirrel
    Member

    The 235 6 cyl cast iron powerglide uses a DIFFERENT BELLHOUSING than the 265 V8 cast iron powerglide. It ALSO uses a different adapter.

    The 235 powerglide WILL NOT FIT the v8 engine.
     
  20. Model A Vette
    Joined: Mar 8, 2002
    Posts: 1,070

    Model A Vette
    Member

    I stand corrected! I must admit that I've never been exposed to the 6 cyl PG setup in a car.
    I don't understand why Chevy would make a different trans AND a different adapter for the two engines with PG. I can see them making one trans and an adapter for each of the engines. Perhaps they were trying to adapt the '54 and earlier design?
     
  21. squirrel
    Joined: Sep 23, 2004
    Posts: 47,100

    squirrel
    Member

    The 6 cyl powerglide was designed only to fit a 6 cyl engine, there was no V8 at the time it was designed. So, there are some design "features" that make it inconvenient to use as-is with the V8 engine (such as the ear for the starter nose).

    And they both use an adapter because the design of the transmission requires the bellhousing to be a fully round piece, which requires an adapter to be able to bolt it to the engine, which does not have a round back on it.
     
  22. Model A Vette
    Joined: Mar 8, 2002
    Posts: 1,070

    Model A Vette
    Member

    Squirrel- Thanks for the explaination. The starter use makes sense.
    I still don't understand why the PG case would be different for the two engines if they are both using adapters. I can understand that the internals may be different for strength, shift point, etc. between the 6 and 8 versions.
     
  23. Leadsled51
    Joined: Dec 21, 2001
    Posts: 333

    Leadsled51
    Member

    Thanks to everyone who responded, yes, there are two different bell housings and two different adapters. I think the position of the starter is the main reason for the different bellhousing, the v-8 being in a lower position than the 6. Oh well, looks like I need a v-8 powerglide, here I come want ads!!! By the way, is the rear mount tranny only up to 57? I don't think I want to have to put a crossmember in it!
     
  24. squirrel
    Joined: Sep 23, 2004
    Posts: 47,100

    squirrel
    Member

    55-57 cars used the bellhousing mounts and very front engine mounts, 58-up cars had side engine mounts and rear trans mount.

    You might decide that going to the newer mounting setup is the best way to go, I don't know of too many people who are happy driving one of those cars with the old PG for very long.
     

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