Truck Bellhousing and Muncie M20

Thetransporter2007

Not-quite-so-new-guy
Apr 18, 2021
6
1
Ok guys, I’m new here hoping to get an answer that seems to be plaguing us for some time now in a few ways. I will list the current setup below.

- V6 Malibu converted to a sbc 350 and Muncie M20
- truck bellhousing is attached to the engine (#460486)
- 168 - tooth flywheel
- 11” clutch

Current Fitment issues
————————————
#1 So far there is a problem with the Clutch fork situation and clearance with the floor pan. We then purchased the clutch fork with the bend however it is not reaching the proper angle inside the bellhousing (picture below)

#2 the transmission hole into the truck bellhousing is oversized vs a car. We have purchased the larger transmission bearing retainer only to find that the holes don’t line up vs the other standard retainer.

I am sure we are not the only ones to encounter this issue. Does anyone have any ideas? Or best practices in doing some thing with what we have to make things work?

Thanks in advance guys! 😀

03A2F978-C197-46CF-BB22-FB5614D95667.jpeg
E67FD157-31AF-41E5-863A-08212CA7C80A.jpeg


678A807F-68DB-4FB8-81A7-04EE04975D0C.jpeg
8748F39B-4AED-4756-816C-4700CA5FCDE8.jpeg
 

ssn696

Living in the Past
Supporting Member
Jul 19, 2009
4,970
113
Permanent Temporary
The Gbody bellhousing pivot ball is rotated about 3 degrees counterclockwise. You can see the larger pad cast into the 697 to accept either pivot location. That and the G-body-specific fork with the jog in it are there to clear the floorboard. The typical G-body Chevrolet '606' housing only fits a 153-tooth, 12-3/4" flywheel (right). For 1978 only, I think, there was a '697' casting that fit the 168-tooth 14" flywheel (left). The 697 will fit a 12" clutch. Sorry to say, though, that they are really, really hard to find. However, the overall casting is the same as a standard GM car bellhousing for a 14" flywheel, - you could use the matching straight fork and put a big dent in the floorboard for clearance.

What size flywheel and clutch kit are you running?

If you abandon the approach you are using now, and that curve fork is not useful...let me know. I might buy it from you...
 

Attachments

  • DSCN4037.JPG
    DSCN4037.JPG
    294.6 KB · Views: 24
  • DSCN4041.JPG
    DSCN4041.JPG
    172.5 KB · Views: 26
  • DSCN4042.JPG
    DSCN4042.JPG
    200.1 KB · Views: 19
  • DSCN4462.JPG
    DSCN4462.JPG
    193.5 KB · Views: 22
Last edited:

Thetransporter2007

Not-quite-so-new-guy
Thread starter
Apr 18, 2021
6
1
The Gbody bellhousing pivot ball is rotated about 3 degrees counterclockwise. You can see the larger pad cast into the 697 to accept either pivot location. That and the G-body-specific fork with the jog in it are there to clear the floorboard. The typical G-body Chevrolet '606' housing only fits a 153-tooth, 12-3/4" flywheel (right). For 1978 only, I think, there was a '697' casting that fit the 168-tooth 14" flywheel (left). The 697 will fit a 12" clutch. Sorry to say, though, that they are really, really hard to find. However, the overall casting is the same as a standard GM car bellhousing for a 14" flywheel, - you could use the matching straight fork and put a big dent in the floorboard for clearance.

What size flywheel and clutch kit are you running?

If you abandon the approach you are using now, and that curve fork is not useful...let me know. I might buy it from you...
Thanks SSN, We are using a 14" flywheel and an 11" clutch. It seems like we have a mix of parts here and are trying to find the best way possible to work things out with what we have or the lowest cost solution to resolve our fitment woes but not make it difficult should we do work in this area in the future.

Question possibly about this clutch fork. We could do a few things based on what you are saying:
#1 - find a 697 bell housing and used the curved clutch fork
#2 - use the existing bellhousing, with the "straight" clutch fork and dent the floorboard.
#3 - modify our existing "straight" clutch fork by putting a curve in it, and putting it into the truck bellhousing. (not sure how feel would be)
 

ssn696

Living in the Past
Supporting Member
Jul 19, 2009
4,970
113
Permanent Temporary

Thetransporter2007

Not-quite-so-new-guy
Thread starter
Apr 18, 2021
6
1
The stock GM 14" car bellhousing is a '421' casting. That will solve the input shaft bearing retainer problem. I bet one of these could be had a Craigslist.
Wow this is something I haven't heard of as of yet trying to understand this large selection of bellhousings. Looks like it fits an M20 and the larger flywheel and all. I see that the clutch fork hole is actually in a similar spot to what I have but the hole must be a little different. If it sits in a similar spot, clearance for the curved clutch fork won't be an issue. I will be taking a look at this when I get home from work to check fitment.
 

Thetransporter2007

Not-quite-so-new-guy
Thread starter
Apr 18, 2021
6
1
The stock GM 14" car bellhousing is a '421' casting. That will solve the input shaft bearing retainer problem. I bet one of these could be had a Craigslist.
One more question, do you have the 421 full casting number in case the summit one is not proper? Seems like people are confused about proper fitment of this one when reading the reviews.
 

Similar threads

G-Body Performance Upgrades

GBodyForum is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to amazon.com. Amazon, the Amazon logo, AmazonSupply, and the AmazonSupply logo are trademarks of Amazon.com, Inc. or its affiliates.

Please support GBodyForum Sponsors

Classic Truck ConsolesDixie Restoration DepotMike's MontesP-S-TSouthside Machine PerformanceUMI Performance

ContactAdmin@GBodyForum.comfor info on becoming a sponsor