Assume you are using side motor mounts. Show us what you are using and what you are calling towers. Probably what I call V8 perches. On the trans you would use a universal tubular crossmember cut to fit. Please read the questions asked.. you did not answer what trans you are using. TH350?
The whole process is all about mocking up until it's all good. Motor should nest between frame. Carb mounting surfice needs to be level. The motor with trans is designed to give a 4 deg down pinion angle.
THIS guy has a bunch of videos on V8 to 61 truck. This video I linked shows the motor mounts he used.
There are other blogs doing V8 swap to early 60's trucks.
Members here have done V8 to 60-66 and will join in. The basics are all the same. Mock up, decide how to mount and check all clearances.
