I've done a refreshing of my race motor, replaced some consumables, valve locks. Springs, Rings etc... but for some reason it dont want to start & if the plugs are in, it's a slow spin 28rpm, but if the plugs are out, 135 rpm spin off starter motor. I've replaced the main feed with 35mm cable & soldered new connectors. I've replaced the isolator switch, added extra earth leads from the battery to ign earth sources, plus another earth to the motor plate. It's not spinning fast enough for the Grid to fire when under load, but if the plugs are out, but still in the leads, they spark like crazy. I'm stumped. I've run the 35mm jumper leads direct from the batteries, 2x new 800CA 960CCA Calcium, to direct to the starter, plus other locations, but no go. Who's got an idea I haven't tried already. Oh yeah, Starter motor is a new HD unit too.