On a recent trip to Vrbancic Brothers Racing to witness a dyno pull, we had the chance to chat with Bob and George about the various project engines in their shop. One of their customers brought in an all-stock engine. He wanted to really punch out the ponies with this engine, but didn't want to get rid of the OEM heads. Not for any numbers-matching, auction house reasons, he just wanted a stock appearing engine.
Although an attempt was made to dissuade him from this path for the simple sake of economics and flow numbers, he still insisted that the OEM heads be rebuilt. Admittedly, most of us can probably identify with this situation. Sometimes it's just downright cool to see an old set of double hump heads on top of an engine.
Looking old school cool does come at a price, though. Unless you own a machine shop, there's a good chance that the costs will easily cross the $1,000 mark with upgrades such as cleaning an old set of double hump heads, adding hardened seats, grinding the seats, porting and polishing, fitting new guides, and installing screw-in rocker arms, studs, seals, springs, valves, etc.
It used to be that this was the only way to have higher flowing heads. Most early racers had a secret scientist locked away in a tower where he worked night and day getting those asthmatic heads to breathe. A majority of those old racers were pretty tight lipped about the performance of their heads. Well, the secret is out of the bag-and has been for several years now. The performance of yesteryear's racers is now standard operating procedure for various aftermarket cylinder head companies.
We called all the cylinder head manufacturers we could think of and asked them what their most popular off-the-shelf performance cylinder head is. We also told them that we wanted to present our readers with performance heads available on a realistic budget (given that "realistic" budgets tend to range quite a bit). Judging by the responses we received, it seems the majority of today's bang-for-the-buck performance cylinder heads are the out-of-the-box, pre-assembled type. In no particular order, here's that list we compiled. Stay tuned for next month's big-block cylinder head list.
GM Performance Parts
Vortec 170cc Cast-iron SBC Cylinder head
One of America's favorite high-performance, cast-iron, small-block cylinder heads offers big power at an incredible value. The modified combustion chambers and high-velocity port technology offer impressive power gains at an affordable price. The Vortec head significantly outflows their non-Vortec service replacement head and offers a 20-40 hp increase over earlier cast-iron heads. They will fit 1955-and-later small-blocks, except for the LT1/LT4 and LS family of engines. (These heads do require Vortec-specific intake manifolds).