The M II conversion
What's there looks good I would still add heavy filler panels for the shock towers, longer sub frame to extend under the front seats,, and a ladder , one rail under the rockers and another reinforcement to the rear box area. lincoln versailles used an additional frame stiffner down the center of the Left and right floor pan, Mustangs with the hi po" K ' engine used heavier gage rockers and the convertibles used an additional flat sheetmetal piece to box the rockers ..I would probably make it look like an old nascar engine cage, curved tubing from the cowl to firewall seam under the fenders to the front sub rails. and a tube under the arear where you bolt on the fenders and beef up the radiator support with cross tubing braces. ...I remember an early protype car that they put on big sticky tires and ran the road race track ...the Radiator support flexed and bent. things moved. ...They original objective was not how strong can the chassis be.. but a 'boulevard ride'