Car crafters love competition, and there's nothing like a good shootout to dump fuel on the Chevy versus Ford versus Mopar fire. So it is with the Battle of the Titans comparison of three street-ready small-blocks. The plan was to see which engine could generate the best overall power curve. By now you should be familiar with the rules, but if not, the Cliff's Notes are that the engines couldn't be bigger than 365 ci, they had to run on pump gas, and they had to stick to a budget of $2,500. This was difficult for the Ford and Mopar guys, mainly because these engines cost more to build than a small-block Chevy. But that's the reality of the performance world.
The first man up to the plate was CC's Mopar man Marko Radielovic, who laid down the gauntlet by choosing a "damn the idle vacuum-full speed ahead" Crane cam measuring 242/252 degrees at 0.050-inch tappet lift with a 108 degree lobe separation angle. That friends, falls relatively far from the daily-driver category, but since there were no rules concerning idle vacuum, Marko went for the jugular.
Henry De Los Santos, our resident Ford guy, built a very similar 351W-based small-block using GT-40P iron heads. He splurged on a set of 1.7:1 Crane roller rockers, but when it came time for the cam, Henry chose a more conservative route with a Crane Power Max hydraulic flat-tappet stick with 234/238 degrees at 0.050-inch tappet lift with a similar lobe separation angle of 108 degrees. While the 8-degree-shorter duration at 0.050 on the intake doesn't sound like much, it proved to be the smallest of the three cams and may have hurt the Ford's chances for a stronger finish.
Terry McGean got the nod to construct the Bow Tie engine, and he followed the now-familiar path for the short-block with production-based components and a set of Vortec heads modified by Scoggin-Dickey to accommodate the additional lift of a big Crane PowerMax hydraulic flat-tappet cam. McGean also pumped up the cam with a similar grind to the Mopar with a 244/252 degrees at 0.050-inch tappet lift selection and an even tighter 106-degree lobe separation angle.
All three engines used Edelbrock Performer RPM dual-plane intakes, a Barry Grant Demon 750-cfm carburetor, and similar Hooker chassis headers. All three engines were machined, assembled, and tested at JMS Racing Engines so we didn't have to worry about variations between different dynos.
The classic line is that the combination is what determines the power curve, so we decided to look a little closer at the camshaft numbers relative to the cylinder-head flow data. We couldn't find flow data on the Mopar head, but some info on the GT-40P head indicates that the exhaust side is a little weak (typical of many production Ford small-block heads) and probably could have used a greater exhaust duration to help evacuate the cylinders, especially at higher rpm levels.
Conversely, the Chevy Vortec heads, offer a slightly better exhaust port but really benefit from excellent intake flow numbers in the 0.300- and 0.400-inch valve-lift areas. While max cam lift for the Chevy was more than 0.525 inch, it is the cylinder head's flow potential at the mid-valve lifts that generally contribute to a strong power curve throughout the entire rpm band. This is the case with the Vortec heads. In fact, comparisons of the Vortec heads to the top-10 aftermarket aluminum small-block heads consistently places the Vortec head in the top five category in these mid-lift flow areas. This cannot be emphasized enough, and no doubt it was the cylinder heads that contributed more to the Chevy's success than any other single component.