The Fresh SD-455 On The Dyno
With the Super-Duty engine completely apart, Schappaugh took the opportunity to freshen it up and measure its output on the dyno. The block had been bored 0.030 inch during a previous rebuild, and Willard said it needed only minor boring and honing. It now measures 4.185 inches. The nodular iron crankshaft's stroke remains at 4.21 inches, and total displacement measures just over 463 ci.
A set of forged-aluminum JE pistons ride on the original forged-steel Super-Duty connecting rods, and the pistons and crankshaft's polished journals were treated to new rings and bearings. The No. 16 Super-Duty cylinder heads were milled minimally, and received a complete valve job, but are otherwise untouched. A Comp Cams No. 041 replacement hydraulic flat-tappet cam-shaft was subsituted for a generic replacement with unknown specs.
With the machining complete, and the engine reassembled, Willard placed the Super-Duty engine onto his Land & Sea DYNOmite engine dyno, and proceeded to break in the flat-tappet camshaft and perform a series of full-throttle pulls. The relatively stock Super-Duty 455 cranked out a maximum of 405 hp and 478 lb-ft breathing through its original intake and exhaust manifolds, and 2.25-inch compression-bent head pipes.
Conclusion
What began as a simple task ultimately turned into a major ordeal for Schappaugh. It might seem that since the engine ran suitably prior to this, we could have simply reassembled it without repair. Rather than run the risk of the incident reoccurring in the future, he chose to properly repair the block while the opportunity was present.
Though this particular story ended happily, it's just one example of the many situations hobbyists encounter when dealing with vintage vehicles. When matching-numbers isn't a concern, it might be easier to simply start with another block, but that wasn't necessarily an option in this case. Our story exemplifies the ingenuity that's required when attempting to salvage high-dollar original components, and we happened to throw in a Super-Duty 455 rebuild to boot!