Bit of a project on-going I will reveal all later

I want to thread the end of a stainless bar so I can then screw it into a rover v8 block where originally a head bolt went ..

Any advise what thread it is ect would be great

Thanks

UNC (Unified Coarse) would be an educated guess, US and UK Automotive manufacturers standardised on Unified Threads between the Korean War and about 1970 while these are inch threads but they are not Imperial threads. Ironically the old Imperial threads were only completely phased out the same time as the ISO metric threads were being adopted by UK and to an extent US manufacturers.
After about 1970 new engine and car designs changed to using ISO rather the UNF and UNC.

UNC is very close to BSW. ( British Standard Whitworth) thread as has the same pitch in most common diameters but differs in detail ie flank angle so don't mix BSW and UNC on mission critical parts.


[Edited on 29/7/14 by britishtrident]