what size?

what size is the header bolt on a 327. someone told me it is a 3/8". I need 1 friggen header bolt thats it. im putting my new alternator bracket on and i noticed one of the header bolts is missing.

sounds right to me

3/8 diameter 16 threads per inch... 3/8 16 and about 1.5" long...make sure it is grade 8

thanks

ok well....i put in my alt bracket. but as i was doing so, i noticed that the header bolt i was missing was laying on the frame way on the bottom lol. it must have been there a while cause i bought the car like that. anyway. it broke off instead of falling off. so now i cant put a new bolt in. my alt bracket is a header mount. so now i only have one header bolt holding that part of the bracket on. it seems really sturdy and i fired it up and it didnt move at all. do you think i can run it how it is? im planning on getting new heads in a while anyway.