6 replies to this topic

[Java_Green]

I just started converting my A+ block to 11 studs when I paused and started thinking. At a start I was convinced that the conversion was the way to go (mainly based what I been told during the years) then I paused as I just entered the 2 holes, studied the block, and started analyzing it. Even though the extra stud at the waterpump is free from closest bolt hole for the pump by a small margin, I am not convinced that bolt 10 and 11 will do anything good. In fact, I must say that I am leaning towards the conclusion that mentioned bolt (I think the bolt outside cylinder 4 is fine) might even make the block less reliable, and that without improving the gas tightness of the cylinders.

 

What is your thoughts and experience?

Edited by Java_Green, 07 November 2022 - 08:54 PM.

[nicklouse]

They were never added to the Metro Turbo.

[Steam]

If nine studs and nuts cannot hold compression, then 1 extra stud and a low torqued holding bolt will not make any difference. Been running a HC 1275 for years with the nine studs and nuts with no problems at all.

[Gaz66]

Ive seen quite a few racing engines with the 5/16 bolt hole tapped out to 3/8 and a stud put in.
Two more studs has got to better surely?

[burchy35]

I also only use 9 bolts, I have never had a head gasket go and I have forced induction 73.5 offset bored with plenty of poke. I put it down to using quality parts and machining and also been very well set up on the rollers.
I have only used A+ blocks though, I woukd be interested if it woukd of been different using an older A series block.

[Ethel]

They spent a fortune developing the A+. Revised the head studs, but didn't add any extra: even though they'd experience of doing it previously.

[Steve220]

Depends on your application really. a mildly boosted A series (13psi+) i'd definitely consider it. However most fast road NA applications, unless revving to the moon, don't need it.