Confusion - a12/a15 heads

[twin120ys]

Hi guys

on my a12, it has an unusual bolt pattern for the carb manifold (pictured). I think this is an a15 head as ive see this on some before.

All of my other manifolds have a whole in the center to bolt to head whereas this has two either side?

Any thoughts on what/why my a12 would have this head on it?

Cheers

[classicdat]

Oval port heads as fitted to most A14-15 engines had the 2 upper studs on the inlet manifold. This is an upgrade which allows better 'flow' with having the bigger ports.

[Bartman]

I'm sure there was a round port head which didn't have the center bolt.
I don't know where it came from, but I once had to drill and tap that center hole to fit my round port manifold to a round port head.

[twin120ys]

Interesting.

It is round port. Not sure whether to keep this one and try find a dellorto manifold to fit it, or to go back to a normal head?

Bartman, did you have any trouble re tapping?

[Bartman]

Not much.
Head was off the car though. I just measured three times, and drilled once. From memory, the hole for the stud was right over a head bolt hole. So I couldn't drill too deep.

[twin120ys]

Good to know, cheers

So from what i believe, a a15 dellorto manifold would match up to this head?

[Naki-Fisher]

Yea A15 Manifold will fit, although the ports will be a miss match oval vs round.
I think some of the late model engines changed to this pattern. most of the mini stock boys re drill them so no to much of a drama.