425 question

[Gearheadbill]

I'm new to this board. I'm putting together a 65 425 GS engine, which will power a 1932 Ford coupe. I have all the machine work done, engine is assembled etc. My question is: centered, at the top of the timing cover, is a cast-in round relief/recess, about 1.250/1.500" in dia.This recessed area has a small passage way which connects it to the water passages around the water pump. What goes here? I bought the motor in a completely torn down state, so I have no reference. HELP!!

[Dr. Frankenbuick]

That is for the water manifold between the heads and water pump. An O-ring fits on the manifold and seats in the passage you described. The thermostat housing is on top of the water manifold. Below is a picture of the front of my 425:

[Gearheadbill]

Dr.,

Thanks for the reply. As I was further assembling the externals of the engine yesterday, 2 other things popped up. #1. I am using a spreadbore (Q-jet) intake. The manifold sits the carb at quite a downward angle (front to back) as compared to the squarebore intake. My coupe has some nose down rake anyway; this just adds to the issue of fuel to the rear float bowl (I'm using a Holley spread bore carb). Am I going to be OK or should I place a wedge spacer to flatten out the carb?

#2. Are the upper fan belt pulleys for a 425 interchangeable with other make i.e. Chevy (other)
I do NOT have an upper pulley. Perhaps GM designed interchangeability will help me out here?

Thanks for your time helping out a Buick rookie.

PS. The fuel pump I got with the motor has REALLY small inlet/outlet port size. Can this big motor (mine is modified somewhat) get by with this, or should I go to an electric pump and block off the stocker?

[Dr. Frankenbuick]

Bill,

You will be OK with no spacer under the carb. That is a Quadrajet on mine, and it sat fine in the 66 GS. There was no significant level change when going from the square-bore to the spread-bore intake in that car.

I think you need a Buick specific pulley for the water pump. I have never heard that anything else will fit. I would place an add in the classifieds here, and I bet you can pick one up cheap.

The Nailhead operates in a lower RPM range requiring less air and fuel at the low RPM of the upper RPM limit. In stock form it does not require more than a stock fuel pump. That being said, I am going with a Holley blue pump or Mallory 140 for mine. It has some head porting, a larger cam, a CD ignition system and headers. It will spin a little faster then stock, and move more air/fuel mixture through the engine at the same RPM. I am also using a ½” pick-up and line to the regulator.

Hope that helps. [img]smile.gif[/img]