I am selling a BOP turbo 400. I have no Idea whether it works or not. The casting number is 42H158505. $200 local pickup only. Call or text me at 1-630-287-0219 or email me at timonator@comcast.net Tim
The number you quote sounds more like a partial VIN number. There is a small tag rivited to the right side of the trans. It will have a set of letters and numbers stamped towards the bottom of the tag that will indicate the application and year.
42H indicates it's from a '72 Buick built at Flint. Is a long tail or short tail? Measure the rear most piece.