Hi guys, does anyone know the size of the drain plug on a f54 block.

Thanks Rex

The head is 22mm. but I'm guessing you mean the thread size. Let me get one and check. My guess is 1/2 inch BSPT.

I know it's the same size as the elbow in the back of the head that feeds the heater core.  I've swapped them.  

Yup, 1/2 BSPT. 14 TPI. Tapered pipe thread.

Now, since 1/2 NPT is also 14 TPI, I'll say the likely un-popular thing and suggest you could use the NPT equivalent in its place with little consequence. Happy threading and plugging.

BTW, this was checked on an N42 block. I don't think this varied across the various L6 blocks.

Remind me to put that thing back in....

Edited November 17, 201510 yr by zKars

jim, thank you for the info.. Much appreciated !