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Here are a few options to install a late model dist on an early block and accessory drive.
1. Use a regular late model hold down bracket and the existing 1/4-20 bolt on top of the accessory drive. This works, but since the ¼-20 hole is slightly closer to the distributor than the 5/16” hold down bracket bolt hole in the late model “block flange”, the hold down bracket will tip up somewhat against the distributor and looks unprofessional.
2. Install a modified late model hold down bracket as described above. You can modify the holder yourself or purchase one sold by MMI. This is a cleaner job, and for you DYIers, it really only involves elongating the hole slightly with a round file until the bracket lays flat.
3. Drill and tap a 5/16” coarse threaded bolt hole near the center of the " block flange" (approximately ½” from the rear face of the flange) and use a regular late model hold down bracket with a 5/16” bolt. CAUTON: If you take this route, please be careful to not allow any debris from the drilling and tapping to fall through the opening in the center of the “block flange” and into the crankcase.
A few options to install an early dist on a late model engine.
1. If your late model engine has a ¼-20 bolt on top of the acc drive you can install the early model distributor using the hole in top of the accessory drive in the very same way as you would on your early model engine. You can view the bolt location on the MMI panorama on the home page.
2. If you have a very late model Atomic 4 (circa 1977 and later) it probably does NOT have a ¼ -20 hole in the top of the accessory drive. In those cases you can remove the standard early style hold down bracket from the early model distributor and use the standard late model hold down bracket and 5/16 hole that would have been standard on any late model engine.
A big thanks to Don for patiently walking me thru all this over several E-mails and I hope I did not mess anything up in this synopsis. Dan S/V Marian Claire
1. Use a regular late model hold down bracket and the existing 1/4-20 bolt on top of the accessory drive. This works, but since the ¼-20 hole is slightly closer to the distributor than the 5/16” hold down bracket bolt hole in the late model “block flange”, the hold down bracket will tip up somewhat against the distributor and looks unprofessional.
2. Install a modified late model hold down bracket as described above. You can modify the holder yourself or purchase one sold by MMI. This is a cleaner job, and for you DYIers, it really only involves elongating the hole slightly with a round file until the bracket lays flat.
3. Drill and tap a 5/16” coarse threaded bolt hole near the center of the " block flange" (approximately ½” from the rear face of the flange) and use a regular late model hold down bracket with a 5/16” bolt. CAUTON: If you take this route, please be careful to not allow any debris from the drilling and tapping to fall through the opening in the center of the “block flange” and into the crankcase.
A few options to install an early dist on a late model engine.
1. If your late model engine has a ¼-20 bolt on top of the acc drive you can install the early model distributor using the hole in top of the accessory drive in the very same way as you would on your early model engine. You can view the bolt location on the MMI panorama on the home page.
2. If you have a very late model Atomic 4 (circa 1977 and later) it probably does NOT have a ¼ -20 hole in the top of the accessory drive. In those cases you can remove the standard early style hold down bracket from the early model distributor and use the standard late model hold down bracket and 5/16 hole that would have been standard on any late model engine.
A big thanks to Don for patiently walking me thru all this over several E-mails and I hope I did not mess anything up in this synopsis. Dan S/V Marian Claire
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