With a stock 91 303 TBI which would be the better choice??

 

The MSD 6A and the MSD 6AL are the same with the exception that the 6AL has a built-in "Rev Limiter". The rev is adjustable to either 3K, 6K, 7K, and 8K with plug-in modules.
So as far as performance gain difference between the two there is none.
Take your pick.

 

hmm (that was strange)... n/m

 

Those aren't the only speeds available. Modules are available in 200 RPM increments from 3000 to 10800 RPM.

 

The Chips are actually available from 3000-13,900 in 100 RPM increments. The 3000, 6000, 7000, and 8000 are the most common chips used so we supply them. The output of both units are the same the limiter feature is the difference

Thanks,

Joe
MSD tech

 

What I'm really asking is what function do the chips serve? Do they act as some sort of govenor?

 

They determine what RPM the rev-limiter is activated, this will prevent the motor from accelerating past the chip that you have plugged in. If you blow the tires away, break a drive shaft etc. where the motor is accelerating hard this will catch it and prevent engine damage.

Thanks,

Joe
MSD tech