There is no better time. Couple hours with someone that knows what they are doing. A day or two for someone who does not but still could be done easy enough.
That motor is screaming to be unleashed with just a couple simple upgrades.

These are the 330 engines right?

Exhaust was replaced last season. All brand new. Honestly right now I want to stay as stock as possible. I have had zero motor problems and don't want to open a can of worms by opening them up. I would lik to upgrade the interior and dash before I get into he motors.

Yes sir 330's

One thing you might want to do while the motors are sitting on floor is remove all the freeze plugs on the block and replace them. Easy job. When they are out you can flush block really good and see all the crud and sand that needs to get out of nooks and crannies. Should only take an hour or two per motor. You'll be surprised how much chit is in there.

Air chisel? Screw driver and hammer? How do your flush them? Fire the motors and let the water run through there.

I'd replace bilge pumps and float switch while you are in the neighborhood. Cant get to them without pulling a motor.

That stuff will be replaced for sure.

No, don't run with the freeze plugs out

Take the front mounted water pump off and put a hose in there with the plugs out, if you decide to go that far.

U can also just flush the block with a hose with that same pump off, plug the thermo hole and water will run through Everythjng and back out the other side. With good hose pressure u might be surprised what comes out

DONT TOUCH FREEZEPLUGS !!!!!!!!!!!!!! ANOTHER BIG CAN OF WORMS !!!!!!!!!! Good Luck Josh !!! Call me .....You know I got the good stuff for motors !! hahaha