Re: Oval port conversion to D port
Pistons: 11.5 to 1 compression cast will be OK.
Heads: D port with 1.75 inlet, 1.5 exhaust with exhaust seats. A professional port mods.
Inlet manifold: D port with port matching and internal port mods.
Camshaft: duration of 245 degrees at 0.050 with lift of 0.350 inch.
Rocker rollers: 1.5 or 1.6 ratio that will provide valve lift of 0.500 inch.
Valve springs: Duel 100lb on seat and 250lb open.
Ignition: Recurved dissy with electronic ignition.
Carby: a 40dfav will achieve the 180 HP you are requiring.