thanks John.

I have several AA type blocks around the shop that have been drilled for the extra stud and bolt. I also have a 1275 GT block with the additional threaded holes. How do I know it is a 1275 GT, the guy I got it from told me so. It also had the correct con rods and crank. It is also one of the few closed back blocks I have run across that does not have a hole above the center main. Almost all AA ( known to be AA ) blocks I have had over the years have the hole as well as Spridget 1275 blocks. Shame thsi 1275 GT block was worn out at 73.5 mm and the crank was 20/40 and needing help. While the rods look like AA rods somewhat they are different and I only use A+ Metro type big journal rods. I sold them on to someone needing that type rod. Steve (CTR)

A quick Google turns up this: 

12G1279

1275GT/1275 no tappet chest pre A plus

Most likely a thick flange block as well. Sounds like a great lump to build up.

Possibly an Austin America block that's been drilled for an 11 hole head or also could be from an MG1300.  Notes about this in the Vizard Yellow Bible in the section on blocks. 

Far as I know no 'S' had solid blocks only covers, early GT or or very early ADO16?

I didn't say it was drilled by someone. It's got 11 holes. 


MK 3 S


1275 GT?


something else?

Do you have any idea how hard it is to drill and tap for two studs? 

is this the block #?   12G 1279.  no tappet cover 1300 drilled for 11 studs.

GT lump?

Did the MK 3 S have tappet covers?