Spark Advance Engine POWER!

[Markus Strobl]

>   Also, for peak power and
> performance, the vacuum and centrifugal advances should be in good working
> order and should advance the spark under load or RPMs.  However, in
> American cars, the vacuum advance is (and has been since about 1972) a
> vacuum *retard*.  This does reduce NOX emissions but it is detrimental to
> power and mpg.  Now, I noticed on my '78 Toyota FJ40, that the spark
> 'advance' assembly has two ports. 

[big snip]

> John Brewer

I wouldn't dream of understanding a Toyota (they are weird), but I DO 
understand the workings of the GM HEI distributor (all GMs 75-80 something)
and they have vacuum advance, not retard. 

Markus Strobl      96 Z28 6M Black.   Borla, !CAGS, 1LE shaft, B&M Shifter
Dallas, Texas      1.6 rockers, ported heads, Swaybars, SFC, Crane Springs
F-member 9/93      No times since latest mods               27.5mpg @85mph