To put the Offy 2x1 and Fentons on my 261 I had to grind the Offy to get it to clear the Fentons. I plumbed the Offy for water heat using one of Langdon's plates and some brake line and also had the two zinc plugs heliarced.

I've still got what I'll call a weepy leak- It isn't much of a leak but after the engine's been running for a while there are a few drops of anti-freeze on the front bottom of the Offy.

The water isn't coming from the heli-arced plug and it's definately not coming from the lines or the plate bolted to the bottom. I think I might have ground into the water jacket on the bottom but can't see any cracks. If I could find the crack I'm sure it could be repaired, but I can't seem to find it. Is there anything I can do short of replacing the manifold?

Next time I would definately have the mounting surface of the fentons milled at an angle so they tilt inwards toward the engine rather than grinding the Offy. I would also buy the Offy from Stovebolt rather than Patricks or elsewhere 'cause Tom Langdon heliarcs the plugs on all the manifolds he sells and those other guys don't.

'51 Chevy 1/2 ton w/'62 261, HEI, offy, fentons, dual carter/webbers, t-5 & 12 bolt posi