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My 1275 (12G1279 block) build is nearing completion but I cannot find a water pump that fits.

The impeller of all the pumps I have bought so far always fouls on either the edge of the outer block casing or the No1 cylinder jacket.

Is there a pump available with the impeller set back into the pump rather than sticking out between 9-17mm into the block space.

To make matters worse, all the spare 12G1279 blocks I have around the place seem to accept all the pumps I have purchased so far....but, ironically, I chose the only block that doesn't to be my donor!

Just grind it out to clear...........

but what went there in the first place?

A pump with a smaller impeller

The early 1300 blocks used what was at the time the standard "Mini" pump. This was a small impeller pump. Shortly after its introduction they went over to using the longer impeller "S" specification pump on everything. As has already been suggested simply grind your block out a bit until you have the clearance you need. It was a common mod in the late 60's & early 70's.

Needless to say that when the factory went on to using the largwer impeller pump across the range the tooling for the block was modified slightly.

The actual problem was the extra head stud fouling the impeller. I just couldn't see it in the poor lighting in here. Ground off the end and it fits fine now.
Thanks for your helpful information, Mark.

YMJ wrote:The actual problem was the extra head stud fouling the impeller.

Never had that problem before. Is the block decked somehow or is the bolt a non-original too long item

I overdid the stud length!