Test 16-18: GMPP Vortec cylinder heads, Wilson four-into-one carb spacer, COMP Cams 1.6:1 rockers (March 2003).
The final dyno bash we'll review this month had us swapping cams, rockers, and carb spacers like they were going out of style. DM ended up making a maximum 427 hp and 439 lb-ft of torque. Those are fantastic numbers coming from just a 9.25:1 small-block still running a very small hydraulic camshaft (COMP's XE268H). The Vortec heads had made 23 more peak horsepower than the factory heads we tested-the camel humps (compare Tests 12 and 14).
In March '03 we tried a new Wilson carb spacer and gained some extra power at 3,000 rpm (Test 16). Then, we wrestled rocker arm ratios around and saw some torque improvement with no horsepower losses (Test 17). And we finally swapped in the next bigger COMP cam with the results we were expecting (Test 18), more horsepower upstairs and less torque downstairs.
By Test 18 we think we've reached the pinnacle of affordable small-block performance, and to make any more power we'd have to go with ported cylinder heads and/or a set of more-expensive aftermarket aluminum or maybe still some iron castings. Look for these comparisons in upcoming months. Still, if you follow our recipe, any properly blueprinted, pump gas small-block you build could easily duplicate all of our power figures, while costing only around $3,500 and being a kick to drive everyday.
Test 16: A Wilson 1-inch open carb spacer with a Wilson four-into-one tapered spacer were swapped in.Max 440 tq, 414 hpAvg 418 tq, 334 hp