I helped a friend winterize his raw water cooled, 330hp, 454, alpha 1. We ran about 5 gallons of antifreeze through the system after we warmed it up, and fogged down the motor (2 stroke oil through the carb) We did NOT pull any drain plugs on the engine, I say we should but he has it all buttoned up, is this the essential, or could we just let it be?
Thanks in advance everyone!!

some will say pull them, others will not, i've personally never drained the antifreeze out, my baja with a 454 mpi went to wisconsin last year in jan and everything was good to go for the new owner in the spring

I would...

i also drain it

If you want to be 100% safe, drain it.

If you are going to the trouble of pulling the plugs, I'd done it before hand, then fill with antifreeze, and then leave it full.

If you want to see what protection he has at their point to be absolutely sure, check with an freeze/boil checker. 1 min to check.

If your mixture is 50/50 or stronger and you made sure to run the whole 5 gallons and watched it green out the exhaust, good to go. Many years done here and no probs.

And I agree if you want to do the plugs, pull the thermostat and fill her back up last.

Note: make sure your thermostat opens up before you run the antifreeze.

I live in Canada, so, winterizing is something pretty familiar, lol

A suggestion? If you do
Plan on pulling the drain plugs, replace them with "petcocks" the same thing they install on automotive radiators, then you can just open the petcocks when you want to drain the block, much easier than crawling around in the bilge trying to spin out drain plugs. Some people drain the block, close the petcocks and fill the block with antifreeze/water. I used to just open the petcocks let the water drain and leave them
Open for winter.

Michael

Joe, I've never drained down anti-freezed/winterized engines after they're fogged.

The main question I have is did you drain the block/manifolds down after it was warmed up, then run the antifreeze thru it?

If you ran it on the hose, then switched over to antifreeze without draining it first, I'd be a little worried because you don't get a perfect mixture. I always warm it up fully. Drain the block and manifolds, then run fresh -50 even -60 or -100 thru it.

Panther's right. You should have drained the warm motor and then run AF. Leave the AF in there for corrosion protection.