![]() ![]() ![]() You'll still need the roller lifters, intake, carb (we used the dyno's higher priced 650-cfm Race Demon), ignition, timing gear, and water pump-figure about $1,250 for pieces comparable to the ZZ4's-and you've realized a net savings of about $1,300 over the turnkey ZZ4. If you are considering a new ZZ4, you might want to consider a partial engine assembly, which leaves off the heads, intake, timing cover, water pump, HEI, camshaft, lifters, and carb. The five stages seen here are great for the ZZ4 owner who's ready for that next step, as well as someone considering a new motor. As we've demonstrated, there's a lot more potential lurking in the ZZ4. The strategy of being built for longevity and reliability has worked well for GM, however the ZZ4 is far from being "on the edge" of maximum performance. They build the ZZ4 for durability, and at a standard you'd expect of a production car engine. 474/.510-inch lift), and HEI distributor. In turnkey crate form, it features a four-bolt block, forged steel crank, 10:1 compression hypereutectic pistons, powdered-metal connecting rods, aluminum D-port cylinder heads, dual-plane intake, Holley 770-cfm vacuum-secondary carb, hydraulic roller cam (208/221 degrees duration at. Thumpr Series camshafts is a line of cutting-edge hydraulic roller camshafts for engines originally equipped with flat tappet cams. ![]() The ZZ4 StoryWhen GM Performance Parts decided to create the archetypical crate motor, they didn't undertake the job lightly. A change to the carburetor's power valve may also be necessary if idle vacuum is at or below 7 inches. 570/.554-inch lift), there's only 7 inches of vacuum at idle at 900 rpm, but it has manual brakes. On Hunkins' 496-inch big-block Chevelle, which has the Big Mutha Thumpr (same duration specs as the SBC, but with. Remember that these camshafts will not pull as much vacuum as stock-style camshafts, so if you are running power brakes, check that you have a minimum of 16 inches of vacuum at idle, or the power assist may not function properly-a rude awakening if they fail when you need them most. With the basic Thumpr Cam (PN 12-600-8), a 2,500-plus rpm stall converter is a good idea. When using the Thumpr camshafts, especially the larger Mutha Thumpr (PN 12-601-8), it's recommended that a 3.55:1 ratio rear gearing and 2,800-plus rpm stall converter be employed to help off-the-line acceleration. See what we ranked below 10 Best Thumpr Cam 350: Editor Recommended No products found. The best Thumpr Cam 350 of 2023 is found after hours of research and using all the current models. But there are a few more things worth considering for your specific vehicle combination. In order to be able to offer you the best Thumpr Cam 350 available on the market today, we have compiled a comprehensive Thumpr Cam 350 list. Thumpr Cam ConsiderationsThe Thumpr hydraulic roller cam series from COMP represents state-of-the-art technology with regard to camshaft lobe design and overall timing. ![]()
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