I recently purchased my first V Drive a 70 Stevens with BBC Tunnel Ram with 660 Holley carbs. I`m going over the boat this winter & will be rebuilding the carbs. Before I tear this down I discovered that the slots on the carb shafts for the secondarys have been modified. I believe this was done for a drag car application & not for marine. I believe this was done to make the Car more managable in the pits. The problem is one carb is not opening the secondary at the same time as the other. The first picture shows both carbs at idle. Second-Third picture shows the slots alittle better. Forth-Fifth picture shows at 1/8 throttle opening & the differance in secondary opening. My thought is they should both be opening at the same time. Should the slots be reworked so both open at the same time? Is this delayed secondary a good thing to use in a Flat bottom?