Any tips on cutting on new transom for the steering arm

[panamacitymustang]

Need some help on cutting for the steering arm on the new transom. The boat is a 1991 regal velocity with 454 and bravo 1. Not really sure how much to cut out.
Any help would be appreciated.

 

[alldodge]

It's best done with the drill jig. You would use a whole saw to cut the top and a reciprocating saw to finish. Without the jig I would suggest putting the transom on and moving the arm to each side to ensure it has clearance. The "d" holes are drilled at around a 30 sum degree angle., don't know for sure the angle



The rest for setup

 

[panamacitymustang]

Thanks. I just put the outdrive backing plate on and marked the opening. I used a jig saw a Chisel and hammer and a Dremel to smooth it out. Came out decent. Thank you.