BSA A-7 & A-10 Dual Port Heads/Manifolds
& Single Port Heads
David Comeau
2 Dec 2001- revised 25 Feb 2007

Please note-I have used the casting pn and not the BSA assigned assembly pn 
Please visit fellow BSA enthusiast Myles Raymond's website for additional information on A-10 dual port heads.






67-1102 for A-7

This is the original 1954/55 BSA dual port A-7 (66mm) head. This was in production when a BSA A-7 won the 1954 Daytona 200 race. The valves were intake #67-531-1.30", exhaust #67-532-1.30". The ports are 24mm in diameter. Additional porting work is needed to make them flow.
The production A-7s  came, as shown below, with the 67-1112 single carb manifold.

67-1102/6 for A-10
This head is a head originally conceived for the 66mm bore A-7, but at BSA it was finish manufactured for the 1954-1955 A-10 Road Rocket, bore size 70mm, additionally it was metal stamped with a "6"  to obliterate the original cast  "2".  Note the positioning of the earlier "AM" casting marker. Still with 24mm ports.
The valves would have been the same as the later  67-1106 head, 1958/59 super rocket, intake #67-968-1.41", exhaust #67-967-1.38".
I will be putting in the RGS/competion intake valves #67-961 1.5" into this head. The billet manifolds (see below) I designed were to allow 30mm concentrics to used on this head.

67-1106 for A-10

Below is probably the last version of the dual port A-10 head,  67-1106. It has a "K54 AM" casting.   Also shown are the factory dual carb manifolds. Probably works better on the computer screen than it does on the dyno....

The valves were 1958/59 super rocket, intake #67-968-1.41", exhaust #67-967-1.38".

The right manifold to head  stud holes had to be welded and redrilled since the port matching was very  bad. The port matching on the left one was as original. The carb bolt hole mounting angle on the right manifold is cocked a little. Only partially the result of the mount hole repair, they were off angle before the repair also.