A module-based ignition control limits at whatever value the installed module carries, so the useful rpm points have to be bought as hardware. The odd increment kits sit between the even series values, which is often exactly where a given combination wants its limit. This kit covers the 4,000 rpm range on the odd hundreds.

MSD 87441 4000 Series RPM Module Kit Features:

• Five modules covering 4,100, 4,300, 4,500, 4,700 and 4,900 rpm.
• 200 rpm spacing, offset from the even series kits.
• Plugs into ignition controls that accept rpm limiter modules.
• C.A.R.B. E.O. number D-40-29.