Whats different from a .67 silver head mac/ blue head

[Beau Parsons]

I want to know the difference between a .67 silver head mac, and a blue head mac motor.

Thanks Beau

 

[Andy Brown]

I want to know the difference between a .67 silver head mac, and a blue head mac motor.

Thanks Beau

There were two different silver heads. The original silver head had smaller ports in the case, sleeve and drum, and it had a 13mm carb.

The next version had bigger ports and a 14mm carb. The blue head was next with minor port adjustments and the blue waterjacket and head button to match.

The original Silver head, in stock form, set the 67 hydro Oval and SAW record in Huntsville in 1999. We had only had the engines for a week and they were straight off the drawing board. They still have potential if you find one with a good piston & liner.

 

[Duck899]

I want to know the difference between a .67 silver head mac, and a blue head mac motor.

Thanks Beau

There were two different silver heads. The original silver head had smaller ports in the case, sleeve and drum, and it had a 13mm carb.

The next version had bigger ports and a 14mm carb. The blue head was next with minor port adjustments and the blue waterjacket and head button to match.

The original Silver head, in stock form, set the 67 hydro Oval and SAW record in Huntsville in 1999. We had only had the engines for a week and they were straight off the drawing board. They still have potential if you find one with a good piston & liner.

Didn't the original silver head also have the unbushed drum housing? When did the bushed drum housing come out? I ran the original and just ran a little more oil in the fuel for lubrication of the unbushed drum. In any case they were and still are great engines.

 

[Bob Howard]

I bought a silver head awhile back and changed the button and head to the blue one, it does have a bushed drum. I don't think this engine has more than 1 or 2 tanks of fuel thuogh it.

 

[Tom Foley]

I have an unbushed version that i bought when they first came out ...killer motor to this day with no appreciable wear of any kind ...wish we still had them !! Don Ferrette helped me out with a blue cooling head a few years back and John Knight helped me out with a head button ...two great guys ..THANKS !