Thread size of water drain plug on block

['S'-type]

Could anyone tell me what thread the water jacket drain hole is on the rear of most A series blocks? And if possible a source of a 2" long bolt to suit.

[Spider]

They are 1/4" BSP. Depending on what you need the bolt to do, you might be able to get away with a 1/2" UNF Set Screw.

['S'-type]

Thanks for that.
My engine stand plate attaches to the back of the engine. It uses the petrol pump studs. But that doesn't look like it is strong enough on its own. So I was looking for another attachment point on the back and thought the drain plug hole might give it more stability.
I'm trying to avoid buying the 'proper' front mounting adapter plate for now.

[Spider]

Ha ! I was wondering if that's what you wanted it for ! I attached my Engine Stand between the Pump holes and the Drain, been doing them this way longer than I care to remember. I find I can get the engine and gearbox complete, with all the ancillaries this way, save for the pump (or blanking plate), drain plug and exhaust manifold.

I use a 1/2" UNF x 2" Set Screw here with some spacers.

['S'-type]

Great, that gives me some reassurance! Thanks for your help.