Projects Late Ford Flathead engine mounts

I'm just about to go to a hardware store to get bolts to mount my Mercury 255 flathead into my 53 Customline and was wondering if anyone knew the bolt size of the bolts that go from the engine mount into the engine? If not I guess I will get a couple pairs of bolts from about what I think the size is and hope that it works.

 

3/8th-16 about 3/4 long..Probably too late now, don't know why I didn't see this sooner..

 

I really appreciate it. I went and bought 3/8th-24 and it was wrong. Only got those because that's what my mount bolts are. I will be heading back tomorrow to get the ones you mentioned. I have the others but it's always good to have extra hardware.