Transmission offset angles

[azhelka]

Greetings
I am looking to repower a 1937 Yellow Coach 743 highway coach.  I have removed the old GM gas 707 engine.  Transversely mounted with an old Yellow Coach angle drive manual transmission.    Offset angle appears to be 57 degrees from engine centerline.
I am hoping to repower with a vintage inline 6-71 which should fit. 
Can anyone confirm the offset angle of a Spicer 7141 transmission?  Or is there a more appropriate transmission that I should be considering?
My goal is to have a coach that is mobile and roadworthy for local use as opposed to a long distance hauler.
Thoughts, comments, advice are all welcome.
Thank you
Adam Zhelka
Toronto  Ontario

[buswarrior]

Toronto? Lovely!

The GM experts will be here momentarily about the line in the sand for swapping and keeping your angles matched.

Happy coaching!
Buswarrior

[TomC]

I realize the 6-71 is unique in it's sound and such, but it is getting harder to fine parts and especially harder to find competent mechanics to work on them.
If you're going to go through all the hassle of changing, why not put a modern engine in? A Cummins ISL can be turned up to 450hp and 1250lb/ft torque and then run an Allison V730 with reverser gear. You'll have TWICE the torque of the 6-71 and better fuel mileage. I doubt anyone but the biggest bus nut wouldn't even notice. Good Luck, TomC

[HB of CJ]

U joint installation angles and slight required offsets come to mind.  It is fun setting up drivelines.  Have you considered the oldie but goodie DD 471TI mill?  It might give you more room to work with plus you can always add that very necessary and fun Jake Brake. 

[chessie4905]

Or a 6V-53. Higher rpm range than the 71 series. Beneficial if you have something like 4:55 rear.

[Utahclaimjumper]

 An early C-8.3 Cummins would also be a good choice prior to mid 1998 so no electronics needed,, it also can be turned up.. The best part would be a smaller sized engine and lighter weight with whatever power you wanted..>>>Dan

[luvrbus]

I don't have any idea what the angle is on the Yellow but GM are 57 degrees,the ZF automatic comes in different angles it turns right handed for engines but changes to left turning for the V drive not a bad set up a lot of RTS buses had that setup 

[chessie4905]

53 to 57° seems about right from measuring a 4104 differential as close as I could, and using a protractor on the differential image in the 4104 shop manual. I couldn't find an official listing. However the 4905 is listed at 63° in the service manual.

[luvrbus]

53 to 57° seems about right from measuring a 4104 differential as close as I could, and using a protractor on the differential image in the 4104 shop manual. I couldn't find an official listing. However the 4905 is listed at 63° in the service manual.

Yea leaving the spacer out changes the angle on the 4905 lol don't ask how I know,but it don't work on the 4106

[Boomer]

The person that would know is Ted Campbell at Coach Maintenance.  And he owns a restored 743.  He can answer all your questions.

[chessie4905]

The exact degree offset may be in earlier coach manuals, such as 4103 or earlier.

[luvrbus]

An early C-8.3 Cummins would also be a good choice prior to mid 1998 so no electronics needed,, it also can be turned up.. The best part would be a smaller sized engine and lighter weight with whatever power you wanted..>>>Dan

A DDEC 6L-71 would be a better choice for him