How to do new distributor timing on Mercruiser 7.4 Gen V?

[CLi87]

Your 454 doesn't have thunderbolt 5, it's a 4 that has no base timing mode. Someone referenced an mpi style which no 454 came with.

Just set the base timing to 8 btdc and you're set. And do check total advance, not a huge deal with the 454. It can handle up to 43ish naturally aspirated with no consequences

My distributor and ignition coil wires all go into that module mounted on the exhaust elbow. So I don't need to worry about putting it in base timing mode, just run it at ~700rpm (in the water I'm assuming?) then set it to 8 BTDC?

 

[dubs283]

My distributor and ignition coil wires all go into that module mounted on the exhaust elbow. So I don't need to worry about putting it in base timing mode, just run it at ~700rpm (in the water I'm assuming?) then set it to 8 BTDC?

Yes, if you look close at the casting on the riser mounted module you'll see thunderbolt iv

No base setting required.

But again.....check total advance to ensure 1. It works 2. It's not beyond 43 degrees at 2500-3000 rpm......