Original Thread:
https://www.vintagefordforum.com/for...omatic-advance
FSI offers the so-called 'Zipper" dizzy as well as the 'FSI' dizzy. The Zipper looks nearly identical to the stock A dizzy, but has a fixed advance total of 28°. The springs can be changed to alter the shape of the curve, but the total cannot be changed. It is most suited, IMO, for a stock motor with a 4.2 head. In actuality, if you are running a stock 4.2 head you will not have to change anything at all.
For a higher compression motor, such as the 5.5 or 6.0, the FSI dizzy is able to have the springs changed and the total advance reduced to between 20-23°, by use of a 'shim'. The supplied shim will get you back to about 25°, but I have developed a way to reduce further than that.
If you run a HC head at 28° you WILL do damage.
FSI has the different springs and the shim available.
Personally, I feel this more sophisticated dizzy best suits those owners with an inherent understanding of what timing is all about
You would need access to a timing light to properly set up a modified FSI.
In my opinion FSI makes a quality product
https://www.vintagefordforum.com/for...omatic-advance
FSI offers the so-called 'Zipper" dizzy as well as the 'FSI' dizzy. The Zipper looks nearly identical to the stock A dizzy, but has a fixed advance total of 28°. The springs can be changed to alter the shape of the curve, but the total cannot be changed. It is most suited, IMO, for a stock motor with a 4.2 head. In actuality, if you are running a stock 4.2 head you will not have to change anything at all.
For a higher compression motor, such as the 5.5 or 6.0, the FSI dizzy is able to have the springs changed and the total advance reduced to between 20-23°, by use of a 'shim'. The supplied shim will get you back to about 25°, but I have developed a way to reduce further than that.
If you run a HC head at 28° you WILL do damage.
FSI has the different springs and the shim available.
Personally, I feel this more sophisticated dizzy best suits those owners with an inherent understanding of what timing is all about
You would need access to a timing light to properly set up a modified FSI.
In my opinion FSI makes a quality product
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