Quality costs money! So does performance. But when you weigh the cost compared to the improvement, there's often a point of diminishing return. For example, can you really harness an extra 300 hp for what it would cost to make it?
Last month we provided you with an economical engine buildup that would satisfy most of us as a street-only performer. For less than $2,300 we showed you an engine package that produced a real-world 318 hp and 365 lb-ft of torque-great numbers for a solid street cruiser. And when you add in that the engine idled perfectly and created 17 inches of vacuum, who could ask for more? Well, there are those out there who wouldn't gripe at adding a few more ponies. So we decided to go back to Vrbancic Brother's Racing to see if we could up the ante without emptying our wallet.
What Bob and George proposed was a simple swap of the heads, intake, and rocker arms to see what the results would be. And it just so happened they had a set of Holley aluminum castings and a corresponding intake manifold sitting idle while they rebuilt one of their mule motors. This presented us with the perfect chance to see how much of a difference these simple upgrades would yield.
To set the stage, the heads on our "econo" 350 from last month were completely refurbished cast-iron models featuring 2.02-inch intake and 1.60-inch exhaust valves. The intake manifold was a standard dual-plane aluminum high rise, and the package included factory-style stamped-steel rocker arms. For the sake of keeping costs down, we limited it to those three items. (We could have changed the cam for a more aggressive design and probably picked up more power, but that would have meant taking the pan and timing cover off, which effectively would have added to the cost. If you were taking this build approach from the start, though, you could simply decide on a different cam and the cost would probably be the same.) All other factors such as timing, carb, and fuel used remained the same. That way we could zero in on just how much those extra ponies were realistically going to cost.
After an hour or so of removing the iron heads and swapping on the Holley castings, Holley intake and roller-tipped aluminum rocker arms, it was on to the DTS dyno for a testdrive.
Since the engine was basically in the same condition as when we signed off last month, it sparked to life with little effort. And after a valve readjustment, George put it through its paces for a handful of pulls. The result of our swap was an impressive 57 hp and 42 pounds of torque, giving us a bona fide 375-horse, 400-plus-lb-ft, 355-inch small-block complete for less than $3,000! (We figured this total by subtracting the cost of the heads and intake from the original package Wayne's sells for less than $1,800 and then adding in the price of the Holley parts, plus the carb and distributor.) And they say bargains are hard to find.