How to Build a Stroker Small-Block Chevy For $1,950

Hydraulic Roller Secrets
The main reason Moore went looking for a one-piece rear main seal small-block Chevy in the first place was because he knew that a hydraulic roller lifter cam would generate a bit more power than the more traditional flat-tappet hydraulic version. By using a one-piece rear main seal engine set up for factory hydraulic roller lifters, he also knew he could find used lifters for next to nothing. We outlined the details of this idea in the Oct. '07 issue in "Secrets of the Cheap Hydraulic Roller Cams." The essential element in this story is that used hydraulic roller lifters can be safely run on either new or used hydraulic roller camshafts. Combine this concept with the fact that used factory small-block hydraulic roller lifters are extremely plentiful in junkyards and you have several of the main ingredients for a budget small-block performance engine. It doesn't get much easier.

A Question Of Balance
One of the confusing things about the one-piece rear main seal small-block Chevys is internal versus external balance. All production two-piece rear main seal, internally balanced small-block Chevys employ a small offset weight on the flywheel end of the crankshaft. When GM converted to the one-piece rear main seal (still internally balanced), it was not possible to add that small eccentric weight on the aft end of the crank. So it was added to the flywheel or flexplate. However, the harmonic balancer still remained an internally balanced component, meaning that it has no external eccentric weight.

Now add an externally balanced stroker 385 crank to a one-piece rear main seal block, and it gets a little more complicated. Some stroker crank assemblies are offered as internally balanced, but they still require the standard one-piece rear main seal eccentric weight. In Moore's case, this engine was equipped with an externally balanced Scat one-piece rear main seal crank. This means this engine required a standard 400-style harmonic balancer in the front while retaining the standard one-piece rear main seal flywheel/flexplate. Scat actually recommends adding a 1-inch-diameter slug of Mallory metal in the first counterweight and "internally" balancing this stroker crank, which would allow the use of a standard noncounterweighted harmonic balancer. Either path is acceptable, so Moore stuck with his original balancer but did have the whole rotating assembly balanced with the new pistons.

Testing Ironclad
After Moore had carefully assembled the 385, we trundled it out to Westech Performance Group for a chance to abuse it on the SuperFlow dyno. Compared to a few of the massive parts comparison tests we've subjected Steve Brul to recently, this test was really more of a fun day since all we wanted to do was see how much power we could squeeze out of old Ironclad.

With the used dual-plane and the relic Holley carburetor sitting on top of an obvious pair of plain-Jane iron heads, the engine struck a not-too-imposing figure on Westech's dyno, which has been witness to 2,000hp, turbocharged, 540ci Rat boat motors. Another minor advantage of a hydraulic roller cam is that we didn't have to sweat breaking in the cam or bother with extra zinc-enhanced additives. We just dumped in 5 quarts of Pennzoil and ran the engine through a complete warmup until we had sufficient heat in the oil to ensure everything was up to temperature.

The first few pulls established that the engine liked 36 degrees of ignition timing, and we messed around with jetting the Holley carb and ascertaining that the vacuum-secondary throttle blades were fully opened under power. Moore had placed the jetting slightly richer than stock, and we went a couple of sizes leaner in search of more power, but stopped when it became apparent that leaning the jetting at the lower end of the rpm scale only hurt the peak power. This demanded an overall jetting compromise that is also typical of street-type carburetors. We felt it was beyond the scope of this engine's budget nature to dive too deeply into the carburetor.

Our best pull out of over 20 runs on the engine netted an impressive peak torque of 439 lb-ft at a very streetable 3,900 rpm, while best power occurred at a conservative 5,300 rpm with a 383hp number. While we were hoping for slightly more power, the payoff is both a strong small-block that's easily capable of low-13- to high-12-second dragstrip passes but also excellent boulevard manners as a result of the conservative hydraulic roller cam. This motor could easily make more power with a better set of heads, but on the cash-strapped street-hero scale, this is an Ironclad winner.

Stock lift at 1.5:1 rocker ratio is 0.502 inch. This cam is listed with higher lift because of the 1.6:1 rocker ratio used on the exhaust side only.

By Jeff Smith

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