How many gallons of anti freeze should my 502 block and manifolds hold?

MY 454 held about two.

The 454 mag block holds 4 gallons of liquid total, not counting the manifolds or the hoses that run from the seawater pump, through the coolers and up to the thermostat housing.

DITTO on what Mentalpause said. I always use 6 on a big block and 5 on a small block. If its a 540 or bigger and has a sea strainer and inter cooler lines and big headers I use 8 to 9 gallons.

John S.

I just did my tall deck 540's (engines only not all the accessories) and used 5 gallons per motor. I test the anti freeze as it comes out the exaust just for added comfort level.

just put six gallons in my 502 yesterday. poured it in, didn't suck it in. that includes engine, manifolds, and pouring some through the oil and ps coolers until it came out the outdrive.

block holds alittle less then 3 gals, manifolds hold about 1 gal each and then add for coolers, strainers, ect so have to agree with pwrbt33

Clearly you are getting different opinions here. On my 454 mag I tested it by draining the engine completely, then disconnecting the hose that leads from the thermostat housing to the water pump. I disconnected it from the thermostat housing and started pouring water back in down the hose through the water pump into the block. Right at 4 gallons the water started back flowing out of the thermostat housing where I disconnected the hose from it. That is why I've always believed that block holds 4 gallons.

It would surprise me if a 502 held less - but I have never tested the 502. Maybe the best thing for you to do is drain your block and fill it back up and measure how much you put in.

Why are you guys filling your motors? I have always drained and added a gallon back into the block and 1 gal in each manifold. Am I missing something here?

by filling the block you are protecting the water jackets and making sure no residual water in the subsystems (water pump,coolers, ect) will freeze...if not might as well just drain it