They are designed to increase horsepower and. Fix that first, then a bigger cam will have what it needs to build power higher up in the RPM range.ĪFR 180s (64cc chamber to maintain compression) + GMPP LT4 Hotcam would probably be well over 400HP, and still have very docile street manners. These LT4 Hot Cams from Chevrolet Performance are direct replacements for your stock LT4 hydraulic roller cam. But the basic restriction in the motor is the heads, no matter how you slice it. As for fuel requirements, with the HotCam degreed in on a 110 ICL, and your aluminum heads, you should be fine running 87 octane with 9.6- 9.8:1. Itll peak HP around 5,300, and be great for towing. A real 400HP with just a head swap? Maybe not- the stock ZZ4 cam is probably just too small to hit that number. In a 383ci, this 273/281 duration cam will have the same power band as a 264/272 seat duration cam in a 350ci engine. A small set of AFRs should blow them into the weeds. its a 1987 Corvette,355 Hypereutectic flat tops,zz4 cam and lt4 springs,3.07 gears,TH700R4 with a B&M Transkit (Raybestos Stage I friction and clutches) + Street/Strip mode Shift kit,B&M Holeshot 2400 RPM Torque Converter. And the Fastburn heads are nothing special in the world of aftermarket heads. GM's 'Fastburn 385' crate motor is the ZZ4 with the factory Fastburn Vortec-style heads bolted on top, generating 30 more HP with NO other changes. After you upgrade the heads THEN do a cam swap and you get the big payoff. 500 LiftRunning on a carb intake for first start up.Switched to EFI in the truck.See this engine in. A swap to a set of mild AFRs like the littlest 180s should be worth a much bigger bump in power than any cam swap. 5.7L Vortec Crate EngineGM LT4 Hot Cam 218/228.

525' lift on both sides (with 1.6 rockers) 112 LSA. The core problem is that the heads just don't flow that well. As far as cam specs go, here are the lt4 hot cam specs 218/228. GM tested that motor with the Hotcam and it picked up just a few HP at the cost of a few ft-lbs of torque. The heads and cam are dialed in to eachother to the point you can't really get much from a cam swap. The ZZ4 is a well-matched combo from the factory.

Lt4 hot cam vortec 350