Got this '71 350 Rocket and when I was putting a new waterpump on it one of the lower bolts that goes into the front cover on the engine, not into the block itself, stripped the threads in the hole I think. I was wratcheting it on and when it got to where it almost seemed like it should be getting tight it started spinning freely.
So I think it's a 1/4" bolt with a 20 thread pitch. The holes in the front cover don't have much meat around them but I'm wondering if anybody else has done this and knows if I could get away with upping the size up to I think 9/16"? I don't know much about tapping a hole either, do I just drill into it with a 9/16" drill and tap it with a 9/16" tap? Or is there a better solution? Maybe this bolt could be left off being that it's just 1 of many and isn't going into the block anyhow?

 

I don't think you want to be drilling into the cover since that would send metal shavings into your oil pan. I think the best solution is to get a different cover or weld a nut onto the back of your cover.

 

EVERYBODY has done this at least once. The small bolts on the water pump are self tapping and only screw into the sheet metal front cover. You need to be VERY careful not to overtorque them - that's what torque wrenches are for. Do not simply drill this out, since the cover is formed on the backside to provide a little more bite for the screws. The best way is to remove the front cover and either weld a nut on the backside or use a hammer and punch to squeeze the formed metal smaller so the screw will bite again. Of course, with the cover off, you MIGHTASWELL put in a new timing set...

 

Thanks fellas, ended up taking off the front cover, cutting off stripped insert and welding a new bolt on. Worked perfect! This motor is going in my '81 this weekend for sure now!

 

FYI... NEW front covers are still available through your local GM dealer.

John