Since I am running a G-Force 101A transmission behind the 4 cylinder Atlas motor I needed an adapter between the block and the transmission. I considered making one but decided age wise I'm running low on time and need to buy some things for the car and not try and make them all.
So I bought an adapter plate ....
.... from Marc in Canada who is on the salt with the Black Opel. He sells them mainly to people with Atlas 4200 motors (motor was in the TrailBlazer) that want to run GM transmissions behind the motor in other vehicles. One thing common to the back of the block on the Atlas motors and other GM motors is that the locating dowels for the bellhousing are in the same place in relation to the center of the crank and transmission input shaft. This does simplify the task if you want to make your own and I explain how on the following page on the site about the adapter plate.......
http://purplesagetradingpost.com/sumner/bvillecar-4/construction%20page-136.html... and you can find more pictures and info there as always.
There was a small problem in using Marc's adapter on the 2900 engine and it would also hold true for the 5 cylinder motor. That is...
... they have a balance shaft on each side of the motor where the 6 cylinder 4200 has none. The balance shafts have covers on them at the back of the block and the cover on the left side was contacting the adapter....
... at the cover and the two bolts as shown above. The bolts were exchanged ...
..... for allen head screws and that helped a lot.
Some time in the mill and boring into the adapter slightly from the block side where the lower screw was, took care of it all. The mill work could of been done with a grinder also
...So now that the adapter is clearanced and mounted I could move onto the SFI bellhousing and mounting it. That is next.
More info on the above here....
http://purplesagetradingpost.com/sumner/bvillecar-4/construction%20page-136.htmlI sent Marc a pattern of the cutout and future adapters for the 4 and 5 cylinder engines should be pre-clearanced. Marc's adapter is a precision made piece that I highly recommend getting and the price is very reasonable. I have a link to his site on the build page above,
Sum