Use extreme cautioun with any modifications to the divider. We have recorded some significant LOSSES in power taking out the divider or even modifying them. A small notch or divit between the secondary throttle plates is fine, or use an open gasket.
The effectiveness of a spacer can only be measured with dyno and/or track testing. I've done a lot of this here, and the only spacer I've tested which showed some improvments at the track was a semi-open spacer.
4 hole, fully open, and fully divider spacers ran SLOWER at the track on my 455 than no spacer at all.
The semi-open spacer still ran .02 seconds slower, but almost 2mph faster......Cliff
