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Speed Secrets: Making Easy 350 SBC Power with Vortec Heads!

Richard Holdener with Speed Secrets has paired up with Comp Cams to showcase some very wild builds over the years. A good portion of which required a fair amount of funding to accomplish, but a decent amount of horsepower gains doesn’t have to break the bank or leave your wallet empty. Starting off with a 350 cubic inch crate engine for a 1973-1985 GM truck application that’s not exactly designed with high performance in mind, Richard and the Comp team demonstrate an inexpensive way to meet your peak performance goals. 

As advertised this 350 cubic inch GM crate engine is rated at a whopping 190 HP and was supplied by GM as a long block, so it did have to be completed with an adequate induction system. With a 4 barrel carburetor, dual plane intake, a distributor, a set of long tube headers, and an electric water pump this engine actually produced 263 HP @ 4,400 RPM and 348 Lb-Ft of torque @ 3,500 RPM on the Dyno, despite GMs original low power rating. While this 4 bolt block with mild cam timing and small valve cylinder heads with 76 cc combustion chambers combination provides good power for a truck application, it definitely could use some more power. 

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First on the list of upgrades is the camshaft. Because the flat tappet design is much less expensive than the typical hydraulic roller camshaft but still offers great performance, Richard replaced the stock cam with Comps XM270H camshaft that features a .480/.490 lift, 226/236 duration, and a 112 LSA. Even though the engine is new, he also upgraded to a set of 812 Comp lifters. With camshaft alone, big power gains are a given but also upgrading the cylinder heads would mean even more power. Vortec heads offer more flow and a smaller combustion chamber, both of which will increase power. To get the heads to cooperate with the camshaft a valve spring upgrade was required in the form of a set of beehive 26915 springs from Comp Cams and Speedmaster supplied a dual plane intake manifold with a bolt pattern designed specifically for Vortec heads.

Retaining the same carb, distributor and long tube headers, the power output jumped all the way up to 353 HP and 391 Lb-Ft of torque for a gain of 90 HP and 40 Lb-Ft of torque. Proving exactly what the right camshaft and cylinder heads has to offer a GM crate engine. However, there is an even cheaper way of going about this. By going to the junkyard and picking up a late model GM Vortec headed truck engine, you basically have everything besides the cam, lifters and valve springs. All of which you can pick up from Comp Cams. With a trip to the junkyard and placing an easy Comp Cams order you’ve got this combination for half the price. 

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