water obstruction

[models916]

Talking to a guy at a local show who told me the 348/409 overheating problem was because of a casting obstruction inside the openings for the water pump. Just grind them out and everything is fine. Hmmm..... didn't know there was a problem so to speak? Anybody heard of this? I can't look at my block as it is at the engine shop.

[fatride]

Yes I've heard about the casting "flash" obstucting the flow on some 348/409 blocks. All the blocks I have looked at that were "stock" had some form of casting flash, some more than others. I have removed the flash from the engine blocks that I have used. Unless the flash is excessive I don't think it will cure a hot condition. Removing the casting flash from the water ports behind the water pump is part of my routine that includes grinding the flash from the entire block.

[jim_ss409]

I also ground the flash off the block but even with the flash left in, the holes in the block are much bigger that the coresponding hole in the water pump.

[models916]

But more to the point. Was there a problem with overheating in W engines in general? Does a modern 1" two tube radiator cure the old problem if there was one? I did buy one of those Flow Cooler anti-cavitation plates for my water pump inpelller only to see the original impeller already has it on from the factory. Unlike most small blocks. Maybe modern rebuilt water pumps use the small block impeller and would cause some problems with flow.

[jim_ss409]

If you go to the C. H. Enterpizes site and look at the frequently asked questions there's a section about overheating that's worth reading. ( there's a link on the links page of this site ) Curt doesn't think these engines are any more prone to overheating than any other engine of this size. I'm running a repro 4 core rad from Showcars in front of my 476ci stroker and I've yet to see the gauge go past 195 deg. I did have an overheating problem with my last 409 that turned out to be a worn out, or leaked out :dunno thermatic fan clutch.