As the heading states I want to swap an unused high volume oil pump for a standard oil pump as I have just replaced the camshaft and the pump no longer fits. I only bought the high volume unit as I couldn't find a standard one anywhere. The pump needs to fit an Engle camshaft.
Barry

You can make it fit Barry by adjusting the depth of the drive shaft in the gear. Make sure you do a trial fit to check for clearance as sometimes you may need to grind some clearance into the back of the pump for the 4 rivet cam.
My preference is a 26 mm pump anyway.

as Matt mentioned, Sound like you have interference with the cam gear bolts, switching to Allen heads or clearancing both bolt head and pump gear backside should solve your issue

Matt, it's the body that's interfering not the gear shaft. I wanted a standard pump just don't ask what happened to the old one!! It's a 3 bolt cam and the fit is way out by about 5 mm!.....very slight exaggeration there, it's 3.5mm

Barry, all 3 rivet cams are the same, as far as the pump is concerned. Maybe the cam gear bolts are wrong, ie. too large in the head.
You can take material off the pump body but obviously only a limited amount, and it depends on where.

I've got a couple of good used standard ones here northside brissy if it helps.

Matt, I'll give it a go there, cheers and pfillery I'll keep you in mind.