How much antifreeze for a big block.
If I pull the engines drain plugs, do i still need to fill w/ anitfreeze?

W/ my 454 I would warm it up real well and change the oil and drive oil, then warm it up again and drain the block and risers, then start it up and put in approx. 3 gallons of the pink stuff until it came out the exhaust tips, with about 1/2 a gallon left I would pour mystery oil down the carb until she quit, and then drain the block and risers again.

If level and you pull the drain plugs, the big recirc hose on the front and the hoses around the oil coolers and raw water pump(this layout varies greatly from boat to boat) then it will be empty and antifreeze is not needed. Some add it to help with corrosion if salt use.

There could be some pockets of water left behind, so running Anti-freeze through the entire system is a good idea...

Ditto all above..... After draining motor and putting plugs back in, I have a large bucket I put under the outdrive and fill with pink antifreeze, I put a bilge pump in it and connect it to the ear muffs on the outdrive. I also have a makeshift plastic sheet taped to the transom which flows exhaust fluid antifreeze back into bucket. This allows me to run engine as long as I want on the antifreeze, well until it warms up anyway. Now I know I've got antifreeze everywhere and the engine is ready for the oil change, fogging, lube entire engine down with CRC lubricant. When done, I pull the plugs on the engine again and collect the pink stuff which can be used again. You can test the pink stuff with any antifreeze tester which is a buck or two at any store... My big block holds 5 gallons of antifreeze, so I have about 10 gallons in my bucket to start with.

I'm in PA. and I don't trust leaving any water in the engine with how much cold we get up here....

Good luck!

Ive got the hose fittings (fresh water flush) inside the engine compartment. Is there a way to hook antifreeze up to those to fill the engines?

Same thing with changing all the fluids in motor and drives. I run the engine long enough for the temp to get to operating temp and shut it down. Place a 5 gallon bucket on the swim platform that has a short hose and valve coming out of the bottom that runs down to a set of earmuffs. (The bucket/ valve/ fitting was easy to make and they sell these contraptions complete now) Fill the bucket w/ 4 gallons of pink anti-freeze and re-start the engine letting gravity feed the anit-freeze to the engine. Carberd motors I would fog down w/ fogging oil, but have been told not to do this with EFI's.

For the $2.99/gal the pink stuff costs, does it pay to take a chance?...NO!!!

Yes, you can just use a short hose from the bottle to the fittings, it will suck it right from the bottle. This is much prefered to the flush muffs, they let in some air and can cause overheat in big blocks.

Camco has a winterizing kit with a 5 gallon tank and hose with connectors that will hook right up to your freshwater flush fittings. Can also set up to hook up to a drive muff if no fresh water flush. Can custom mix antifeeze (%) in the tank. Available at West Marine, probably Boat U.S. too.