No doubt if GM made a 90 degree adapter for these engines it will fit right. I would measure and double check any aftermarket adapter to be sure it will position the filter far enough off the face of the block to clear the big pan rail flange that is in the way. Changing the oil in these engines is a messy job. I have a piece of aluminum I bent up to slip under the filter and let the oil run down it to a pan and even then I lay rags on the crossmember. After all that there is still oil to clean off the bottom of the block.
Only one I ever saw that was worse was a V8 Nash that the filter screwed down onto the top of the engine. When Nash folded up shop that guy must have got a job at Chevy!
