Like everything else in life, our quest for performance requires that we accept the good with the bad. Case in point: building or improving the performance of your small-block Chevy. The good side of the equation is that the small-block has been around since the mid '50s and, as such, has a tremendous following both in terms of enthusiasts and the performance industry. The benefit of the popularity is that there is an abundance of performance hardware available both directly from Chevrolet in the form of their GMPP catalog as well as from the aftermarket. The availability means that we have a great many choices when it comes time to build or upgrade our existing powerplant.
The downside to the abundance of aftermarket availability means that not only do we have enough choices, but often times we have too many. By this we mean that the vast array of different manufacturers and associated components can be nearly overwhelming. Which heads go with which cams and why can't someone go to the trouble of assembling the various accessory components required to duplicate the advertised test results?
Well, fellow enthusiasts, TFS responded with not one, but with a number of different performance packages that are designed to take the guesswork out of building a small-block Chevy. The TFS small-block Chevy engine kits are available in power ranges from mild to wild. In performance terms, the mild-to-wild designation translates into power numbers ranging from 350 hp to over 500.
Not surprisingly, the power range offered by the various TFS kits covers the vast majority of street machine buildups. Sure, we all want to brag about having 600hp small-blocks, but the reality is that short of forced induction, not many street small-blocks can achieve that power level with any kind of streetability. TFS took this fact into account when designing these engine kits, as they offer 18 degree cylinder heads that will produce a great deal more power, but not many daily drivers will require the kind of flow offered by the race heads. For most of us, all we want (or need) is a good set of performance aluminum heads and matching cam to go with a four-barrel carb and dual-plane intake. Such a combination should produce gobs of horsepower and torque combined with thousands and thousands of trouble-free miles.
We wanted to put one of these kits to the test, so we immediately contacted Trick Flow Specialties. The highlight of the supplied engine kit was naturally the TFS 23 degree aluminum cylinder heads. Right off the bat, the aluminum heads offered a performance gain by reducing the curb weight compared to a set of traditional cast-iron heads. Those few enthusiasts who still cling to the notion that cast-iron heads are somehow stronger or in some way superior to aluminum heads should join the rest of us here in reality. Aluminum heads offer nothing but advantages in weight, reduced detonation and repairability compared to the old-tech iron heads, to say nothing of the superior port and chamber designs that greatly improve power potential. Even the very best fuelie, camel-back or turbo heads are no match for a set of off-the-shelf 23 degree TFS aluminum heads. Cylinder head port design has come a long way since the introduction of the small-block, even since the musclecar era. It should come as no surprise that a modern, computer-designed aluminum head can out-perform a set of the early GM performance castings, to say nothing of a set of the more pedestrian stockers.
According to the TFS literature, the requirements for achieving the desired power results from any of its engine kits required only a few simple items. Naturally one of those requirements was a suitable 350 Chevy (or stroker variant) short-block. The other important items included a Holley (or equivalent) performance four-barrel carburetor and a matching four-barrel intake manifold. The size of the carburetor and specific intake manifold depended on your chosen power output. TFS specified a dual-plane Edelbrock Performer intake and a 600-cfm Holley carb for the lower performance 350hp kit, but stepped up the induction system to a 750 Holley double-pumper and a Performer RPM Air Gap or Victor Jr., depending on the exact power level.
In each case, TFS specified a camshaft tailored to work with the cylinder heads and induction system to produce the desired power level. Remember, it is important to tailor the cam timing, induction system and cylinder head flow (and port volume) to work together to produce optimum power. The wrong choice on just one component can literally ruin a perfectly good buildup. This is why matched systems like the engine kit from TFS make so much sense.
For our needs, we chose the Pro Street Engine Kit designed to produce 445 hp and 405 lb-ft of torque (according to the specs supplied by Trick Flow). As indicated, this included the impressive TFS 23 degree performance aluminum heads. According to TFS, the 23 degree small-block heads flowed over 250 cfm on the intake and nearly 190 cfm on the exhaust. These flow figures jump up by 3 to 6 cfm if you opted for the optional CNC combustion chambers, which we did not. These are pretty impressive figures for intake and exhaust ports that measure 195 cc and 75 cc, respectively. Of course, it is possible to greatly improve the flow rate of the heads with additional porting (TFS now offers CNC versions of the 23 degree heads), but we wanted to check out the results of the as-cast heads as delivered by TFS. Check out the supplied airflow data on page 96 for a complete rundown on the flow specs for the TFS aluminum heads.