Does anyone know what size the threads are on a oil pan drain plug for a 500 EFI motor are?
Are they 1/2-20? Summit racing offers an oil drain pet cock that looks like it would work for me but I'm not sure of the thread size of the one that's in there.
Cardshark

If the 500 efi is a gen VI pan like all the other big blocks, then no, it is not 1/2-20. I tried it.

Late model pans are 12mm X 1.75 I believe.

Craig

Craig is right. they're 12mm X 1.75

it is the 12x 1.75mm
I just ordered two drain hoses from Overtons
Tired of pumping out the oil from top
Now I will just be able to let gravity do the work like in all my old boats
Merc got smart when they added this hose to the new 496's

I'm just jealous that you guys can get to the oil pan drain at all...

SUCK IT OUT !!!!!!!!

rick32

MNfastboat... I have seen these drain hoses used a cool way.. searay does it.. They have the end of that drain hose attached to a fine 1/16 wire cable that is attached to back of the drain plug, when you pull the plug you can pull the hose right out the drain hole, undo the cover and drain it right in a pan.. It might be harder with twins..

Dyno prefers to blow 'em up before he needs to change the oil. Doesn't need to winterize that way either.

I just installed the Merc drain kit on my HP500EFI. Merc makes two kits, and I am 99% sure I used the metric one. It is a slick set up, but you still need to warm up the motor to drain the oil, as that hose is still pretty small to fit through the bilge drain hole. When you are installing these, have the tongue wheel on your trailer all the way up, maybe resting on a cinder block. There is still almost at full quart left in the pan when you suck it out the dipstick. When you pull the plug, you want to contain this slick at the back of your bilge. A nice idea I found out about (after I did mine), was slice a flat anti-freeze jug in half, and lay it under your pan, when you pull that original drain plug out. It will help contain the oil left in the pan.

Brian