A GMC 248 is, potentially, a much more powerful engine -- especially in low- to mid-range torque -- than a Chevrolet 235. Indeed, if you succeed with the plan you have proposed, you will after much labor exceed the capacity of a Chevrolet 261. Yet a 248 is not exactly a direct replacement for a 235 or 261. It shares the heft, in length and weight, if its "big brothers," but not their potential displacement or power. You may succeed in extracting as much power from a 248 as anyone ever has, but you will not exceed what you could do with a 302 or even a 270, almost certainly with less time, effort, and money.
In another time we used to say, "They ain't no substitute for cubic inches." That may not be as true as it once was: witness Tom Lowe's continuing experiments with the "late model" 250 and 292. We expect that the 250 will exceed the 292 in peak horsepower at maximum rpm, simply because the 250, for several reasons, is not as rev-limited as the 292. i'll be interested in the comparative torque numbers, which is where the most "power" that we perceive in a street engine is derived. Every engine design and configuration has its limitations, and every attempt to modify an engine is a compromise that attempts to overcome those limitations. Those who work with the 235 Chevrolet and the 228-248 GMC are struggling with more limitations than most. We can always hope that those struggles will teach us something that we can apply elsewhere.
God's Peace to you.
d
Inliner #1450
