Water Pump Pulley Clearance

[emorrison96]

While putting together a mock water pump assembly last night I noticed something that disturbed me a bit.  I'm using a PRW aluminum water pump, C5 FE alternator brackets, and a C5AE-8509-C water pump pulley.  Since I'm using the early alternator brackets where the upper bracket uses the same hole as the upper hole on the lower bracket and an ARP bolt with a slightly taller head than stock the bolt head comes VERY close to the pulley sheave.  I didn't measure but it looks like about 1mm or 1/32.  Is this acceptable clearance or something I should be worried about?  The water pump bearing has zero play in it but it looks like if it gets even a slight wobble it will start to make contact.  I've added some pictures below for reference.  Does anybody have any opinions?

[fastback 427]

I would first check belt alignment, just to be sure. I had a problem like that, at 7000 rpm the fan belt would fly off. The clearance looks to close for me. I'd get a button head bolt or similar fastener.

[emorrison96]

Is it possible I don't have the brackets set up correctly?  I know the later ones used 3 separate holes on the water pump; is it possible the upper bracket mounts to the hole where the later model lower bracket bolts to?  That would eliminate the thickness of one bracket on top of another.  I didn't have an engine to look at as I'm putting this one together from scratch.

By the way - for those using the early lower bracket with one of these pumps you'll have to grind off one of the reinforcing webs on the water pump for clearance since the bevel on the bracket actually faces inward.  I think on the stock cast iron pumps this area is flat.  No biggie, just FYI if you decide to use one of these pumps.  I don't know if the Edelbrock is the same or not.

[turbohunter]

I don't know if the Edelbrock is the same or not.

Had to grind my Ed a bit using an aftermarket bracket set up.
But then again had to grind my T bird replacement pump also on a stock set up.
Seems to be a fact of life with replacements.

[jayb]

+1 on a button head cap screw in that position to solve the problem.

[cjshaker]

I like the ARP engine bolt kits, but that's the one place you can't use their bolt/washer combo. Just too thick of a base, and if you grind the head down it doesn't leave enough to get a bite on. You can just eliminate the washer and problem solved. I just use a regular bolt and washer, or a flanged bolt will work, or the button head as others mentioned.

For the life of me I couldn't figure out how you're engine was sitting when you took those pictures, until I realized it's not actually mounted on the engine...lol

[emorrison96]

I do have one of the aftermarket chrome ones for a small block.  The appear to be the same height but it is about 7/8" smaller diameter.  This may have been discussed on here before, but will small block pulleys work on an FE?  Since some of the 427 used about a 7.25" diameter pulley going to a 6.125" seems quite a bit smaller.  I don't plan on spinning this thing past 6K but will that much size differential make that much difference?