Re: 1990 OMC Cobra 5.8
plasma cutter? i feel your pain same engine and i cant even replace the plugs with out pulling the manafolds. what i am thinking is a 1/2 or better a 3/4 inch socket and ratchet and maybe a 5-8 foot pipe if you have room 1 guy holds ratchet in place and the 2nd pulls on the pipe. call me stupid but it works.
if you use air or power your only going to hurt yourself and/or bust the bolt. niether of which you want to do. at least if the bolt busts you can torch it and use vice grips, or use an easy out, depending where it breaks.