Richard Holdener tells you what you need to know about cam swapping your 4.3-liter V6 in this video of Speed Secrets.
To find out how well the ever popular 4.3L V6 would respond to a cam swap, they start off with a fresh rebuild of the 4.3L engine and put it on the dyno. Although originally this engine had an EFI system, for testing purposes it was converted to a simple 4 barrel carburetor setup with a matching manifold and distributor, and since Comp Cams offers cams for both versions of the V6, its not an issue that the engine is a later balance shaft version.
At 207 HP @ 4,700 RPM and 287 Lb-Ft @ 2,800 RPM stock, this is definitely an already torquey V6, and now that they’ve got some baseline numbers, it is time for some modifications. Comp provides the 4.3L with a Comp Magnum 280HR with .525 Lift, 224 duration and 110 LSA. Then, it is back to the dyno where the power house puts down some serious numbers; 251 HP @ 5,200 RPM and 298 Lb-Ft @ 3,500 RPM.
Gains of 44 HP and 11 Lb-Ft of torque are definitely impressive, but if thats not enough they throw a little boost at the torquey 4.3L as well. With the TorqStorm supercharger equipped with a blow off valve installed, the dyno calls to the engine one last time. Putting down 459 HP @ 5,800 RPM and 423 Lb-Ft @ 5,400 RPM, this engine has gone from modestly powerful to crazy with just a cam and a little boost. With a more than 200 HP gain, it is safe to conclude that, with the right cam and a little boost, the 4.3L V6 engine has a lot to gain.