left motor mount

Professor Fate said
273/318 driver's side mounts are wider than 340/360 mounts. Either source a 340/360 driver's mount or just use a 1/2" (actually I think it's 5/8") spacer between the rear engine mount ear and the bracket. It's done all the time.

I did that in about 1973 when I swapped a 340 into my "was" 440-6 '70RR and there was no internet to look it up, either!

From what I've seen of the spool mounts, you could bend the bracket a little bit