Petcock Size? Mercruiser 7.4L

[12guns]

When winterizing my friends Arriva 2452, one of the petcocks stripped out from under the block. It took a lot of work and a pair of vice grips to get it out of the block. I guess it's pretty standard, but didn't know what threads it was or if there's a better replacement than the brass plug w/ the "crimped" wing nut. Any help would be great! Where can I buy them online?

 

[Bondo]

Re: Petcock Size? Mercruiser 7.4L

Ayuh,... The block drains in all the Chevy motors are 1/4" pipe....
I prefer just plain ole brass pipe plugs,...
They take a 9/16" wrench to remove...

 

[12guns]

Re: Petcock Size? Mercruiser 7.4L

That's what I found online, but the plug that I took out is bigger. Closer to 9/16" or 1/2"?? The small inside plug you loosen to drain is about 1/4", but I had to take the whole thing out. Make sense? Any ideas?

 

[Bondo]

Re: Petcock Size? Mercruiser 7.4L

Ayuh,... 1/4" pipe thread is about 3/8", 1/2", Outside OD...

If yer lookin' at a cast iron threaded hole in the bottom of the block rail, it's 1/4" Pipe thread...

 

[12guns]

Re: Petcock Size? Mercruiser 7.4L

Ayuh,... 1/4" pipe thread is about 3/8", 1/2", Outside OD...

If yer lookin' at a cast iron threaded hole in the bottom of the block rail, it's 1/4" Pipe thread...

Thanks for clearing that up, makes more sense now. I'll order a couple online so I have a spare!