Blocking the bypass hose?

[bobcowan]

Originally Posted by madmaxx

By the way 351 blocks have an external hose for the bypass, 302 have the bypass internal to the water pump so from the factory they all have one.

I don't thik that's true. the front cover and water pump are the same on both windsor engines. Might be differant for the 351C or M. But there's no 302C or M, so that still doesn't make sense to me.

Originally Posted by DoneByDoug

HOWEVER, what's up with your gallery pic of the plug on your heater hose connection just below the bypass?

The Windsor water pump has two holes, one next to the other. One is for the bypass, and the other is for the heater. Doesn't matter which one you use.

Drilling a hole in the thrmostat base plate is an old trick that's been around since I was kid (like a century or two ago). It's there to allow you to fill the entire cooling system when cold, as air can escape through the hole and out the filler cap.

Without the hole, water will flow from the filler cap, through the radiater, into the lower hose, the water pump, the block, the heads, up to the back of the thermostat. It will stop somewhere in the block or heads, when air pessure builds up enough to hold the water back.

If you set up the hoses and filler correctly, and drill a 1/8" hole at the 12 o'clock position, you won't have any trouble burping the system. It has no discernable impact on the rate of warm up.