348 oil drain back passages in heads?

[slimpick]

Does anyone have a trick for making sure the oil drain back passages in the heads of a 348 are clear? I see the passage way is more/less a 90 degree intersection of two drilled holes. Is there an easy way to verify this is open?

 

[scott hall]

Run a piece of speedo cable on a drill down the hole. If it has blockage it'll knock it lose.

 

[Jim Sullivan]

Talk to Carmine, he had an issue with drain back holes on his engine.

 

[Carmine]

Run a piece of speedo cable on a drill down the hole. If it has blockage it'll knock it lose.

That's exactly what I did. The time to do it of course, would have been when the heads were off and in the machine shop. But, for some reason, that didn't happen. So, I used a drill and speedo cable with the heads on. I recall a lot of sludge/debris coming out of the oil returns. I think the driver side rear took a while to break through. I guess just an accumulation of things over the years, Carmine.

 

[T-P Auto]

Thanks for the info;
Just got a 58 348,
Had one back in the 70s in a 59 chevy .
Going to put this 348 in a S10 frame with a 350 trans.
No pic yet.
T-P Auto
Tim

 

[slimpick]

Thanks a lot! I'll try the speedo cable and drill.