When figuring out which springs
to buy, knowing your installed height dimension is critical.
Especially if you want to avoid cutting your spring seats. most
shops will tell you it's standard procedure to cut the spring
seats. We have found that there are many different springs available,
which quite often allows us to avoid cutting the spring seats.
if your heads are ported, the roof of the port is directly under
the spring seat. you'll want to be careful selecting your springs.
AS YOU CAN SEE THE INDUSTRY STANDARD
DIMENSION KNOWN AS THE "INSTALLED HEIGHT DIMENSION"
IS MEASURED FROM THE SPOT FACE ON THE HEAD WHERE THE SPRING SITS,
TO THE UNDERSIDE OF THE RETAINER WHERE THE OUTER SPRING TOUCHES.
YOU CAN MAKE THIS MEASUREMENT WITH A SIX INCH METAL MACHINIST
SCALE THAT'S gRADUATED IN TENTHS. YOU CAN SEE IT WELL ENOUGH.
MAKE SURE THE SCALE IS STANDING STRAIGHT SO YOUR MEASUREMENT
WE CAN ALSO AFFECT THE I/H DIMENSION
WITHOUT CUTTING THE SPRING SEAT BY USING DIFFERENT VALVE LENGTHS,
AND OR CUSTOM RETAINERS. WHICH WE CARRY IN STOCK. YOU CANNOT
MAKE THIS MEASUREMENT WITH A PAIR OF STOCK CALIPERS.