i rarely get a chance toplay on the computer,i am taking my stock twincam motor 1/8 overbore-10.5:1 comp 250 degrees dur.&possibly a 45mm mikuni. i used to build automotive race engines and trying to use some of the same concepts.i would like to here from u folks w/your opinions & wonder what i should expect from these upgrades. vinny
The main thing you left over was the head work. A 250 duration cam will do nothing with stock heads. The twin cam heads are the most restrictive part of the motor and you have to improve the flow and upgrade the stock springs with that much lift. (the lift is a presumption on my part based upon the high duration). That combination with the right ignition and head work can yield over 100 HP and torque if done properly.
i have had significant gains w/ porting cast iron automotive heads,i also know one wrong move can destroy the flow figures.iwas thinking of going to .050" larger severe duty s.s.valves and giving the heads a bowlblend,however i dont know if the tc heads will respond to this.