I have an opportunity to purchase an OEM Dual Quad Set-Up for my 66 Skylark GS. I'm told that this is a complete set-up including rebuilt front (without mixture adjustment screws)and rear carbs, intake and chrome air cleaner and knurled hold down nut. The car is an automatic and I'm told that there is a bracket required in order to mount the transmission downshift switch. I do not know if this bracket is included. If not, is it available. What, if any, is the "down-side" to installing this on a completely stock GS? Will there be fuel octane problems with this set-up? The car currently runs quite well on 92-93 octane pump gas.