Originally Posted by Shawnb
I bought a complete running Chev 355 that was built for drag racing and raced for 1 year. I want to use it for a 69 Camaro im going to buy. The motor is 13.1 compression. Are there octane modifires or boostres that can be added to 93 oct fuel that my motor can run on. I plan to buy a good set of aluminum heads. Im dont want to buy $8.00 per gallon gas for 110. I know I can swap to E-85 but I want to do that as a lats resort. Are there other options? I dont plan to race the car. Just street drive. Thanks in advance.
There's 13 to 1 and there's 13 to 1; which is to say you've got to get at the Dynamic Compression Ratio. 13 to 1 as a static is used in race enignes as a means of improving off idle to torque peak performance that is otherwise lost when very long duration which brings a late to close intake valve. This usually needs to also be combined with a lot of gear ratio to essentially prevent the engine from lugging on the bottom end and going into detonation as a result. The lugging period of a drag enging runninng through the gears as it transits the lights may be momentary but it is significant this is where probably half the engines blow up Typically mid strip in the upshifts not form over revving but form detonation either blowing the piston or rod, or wiping the oil film from the rod bearing to journal spinning the bearing with explosive result. So one of the first things you need to know is in crankshaft degrees when does this cam put the intake valve on the seat in the compression cycle. Later begets more SCR to drive an operational DCR range of 8 thru 9 to 1. 8 being street gearing and pump octane friendly and 9 being race gears and gas. You also need the connecting rod length for this calculation, DCR calculators are all over the web when GOOGLED.
Off the top of my head I'd say you'll have to give on compression for the street and maybe even have to calm the cam. A 13:1 the pistons are probably pop-up so figure on their replacement as well.