Flathead Water pump question

Hi,

there are two truck waterpumps at speedy bill´s Store, 1937-48 and 1949-51,
As i got a french block and the original French waterpumps lead to a much higher position of the engine in the frame i wanna exchange them, but by which?
What exactly is the difference between these two?

thank you
Jan

 

I don't have that answer,but I would call Skip Haney in Florida.

 

For your needs, the main dif is the pulley position...there are many internal differences, too.
The '37-48 (two flavors, double pulley ball bearing truck, single pulley bushing car and pickup) and the '49-52 truck pumps have very similar mount height.
Which you use depends on the distributor and front of engine pulleys used. There is a mismatched bypass water hole, too, which can be plugged as needed.
'48 and back had the pulley very close to block and matching crank and gen pulley...late moved the pulley out to clear the sideways distributor.
The late arrangement makes engine unnecessarily long for use in early rods, but engine needs to be built around the early cam to use the shorter arrangement.

 

Bruce, thank you that was the info i needed..

 

The front of my French block is designed to use the 49/53 pump. If you use the early style pump there will be a hole partially exposed at the top of the pump which was a bypass on the late pump. When I was at Chrisman cars a few years ago he pluged the by pass hole and smoothed the block in a effort to make it look like an early block. If your using the side mount late style distributor I would use the 49/53 truck pumps.

 

thanks krylon, thats what i´m gonna do!

 

What is engine going into? If short, like Model A, build engine with early front end and save several inches. If long, choose whatever.

 

Model A..hm that´s kind of an argument Bruce..