First, if one is available for your need then BUY it. At the time these two examples were done there were none on the market---there is now.
First is a straight eight Buick to the 1963 and newer Chevy bell housing bolt pattern and second is a 4 cam Ford Modular engine to an AOD overdrive transmission.
The 37 Buick with a/t came about when wife said she would like to drive it. She had failed miserably on attempts to drive other manual shift rides so it was off to the drawing board.
Back of Buick looks very similar to Stovebolt Chevy's of that era:
[img]https://i.postimg.cc/t7ZBMv9G/Rueben-s-65-Buick-engine-adapter-008.jpg[/img]Had an old driveshaft that the OD was EXACTLY the same as the main bearing bore in a Buick block:
[img]https://i.postimg.cc/pm6wjhZD/Rueben-s-65-Buick-engine-adapter-011.jpg[/img]Used wood for first template as it's much cheaper to scrap out mistakes. The flat plywood on block can be oversized and trimmed later but the plug that fits into the transmission bearing retainer pilot hole in the bell housing must be exact.
[img]https://i.postimg.cc/HcFXR7M4/Rueben-s-65-Buick-engine-adapter-010.jpg[/img]With the mandrel (driveshaft) holding the trans center line true to the crank c/l bolt holes and alignment dowls can be transfer punched through the bell housing bolt holes.
[img]https://i.postimg.cc/CRJvtmxG/Rueben-s-65-Buick-engine-adapter-012.jpg[/img]Flat adapter plate is trimmed to fit. Auto trans flexplate is fitted to Buick crank flange and torque converter spacers made if necessary.
On the Ford the rear flywheel flange is already machined so template just has to have a tight fit hole to center on the flange:
[img]https://i.postimg.cc/47hvP10Q/4-6-to-C4-adaptor-001.jpg[/img]Countersunk holes are made in the plate to give studs for starter mount:
[img]https://i.postimg.cc/bGQ8X74G/4-6-to-C4-adaptor-002.jpg[/img]Starter mounted on studs:
[img]https://i.postimg.cc/SJT60sMP/4-6-to-C4-adaptor-005.jpg[/img]Long alignment pins replaced stock factory dowls to exactly align bell housing, holes drilled, and adapter plate trimmed:
[img]https://i.postimg.cc/681xGdGh/4-6-to-C4-adaptor-006.jpg[/img]The above is just rough templates with final ones made of aluminum plate and exact hole locations being measured onto adapter.
To repeat first line BUY one if available but it looks like the routine will have to be repeated on the 4200 Atlas I6 as I have not found one being made.
