Chevy Small Block Build - Mildly Amusing

How to build a recession-proof 365 hp small-block.

Richard Holdener Oct 1, 2012 0 Comment(s)
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The small-block Chevy has enjoyed a long, happy life. Sure, the current LS derivatives are quite far removed from the original, but millions of Gen I Mouse motors continue to provide the motivation to everything from stationary irrigation pumps to 8-second drag cars to LeMans-winning Corvettes. Naturally, this list also includes all manner of boulevard bruisers, street stompers, and resto rockets. Heck, we've even seen little Chevy's under the hood of brand-X machinery. The continued popularity of the small-block is not surprising. Take a look at the combination of power potential and parts availability, then multiply that by the cost quotient, and you have the makings of a real success story. Add in the countless millions of potential project engines just sitting around at junkyards throughout the world, and it is easy to see why enthusiasts continue to embrace it. In today's economy, the traditional SBC just makes great sense.

True enthusiasts, especially those raised on performance during the heyday of the muscle car-era, may look at this story's subhead and immediately think of the 365hp L76 327. An excellent choice of a small-block to be sure. But alas, this is not an article on how to restore your L76. This one's 350-based, and with cast-iron factory heads and a hydraulic cam, might well be a step up in performance thanks to the broader torque curve. Unlike the high-strung performers of yesteryear, the elevated power offered by this mild mannered combination comes with no penalty in idle quality, drivability, or the need to run over to the local speed emporium or track for gallons of expensive race fuel to achieve maximum performance. No, it'll run all day long on regular unleaded.

Like most rebuild stories, our 365hp mill started out life as something much less extraordinary. The 350 was found rusting away in the bowels of a local wrecking yard. The mid '70s 3/4-ton pickup that housed it was well past its prime, but lurking within was a diamond in the rough. Purchased for a mere $90 (wrecking yard special), the complete engine turned out to be the more-desirable four-bolt main block, though a two-bolt block would certainly suffice for this particular build. The high-mileage motor was disassembled, and found to be in quite good shape. Hardly exotic or even desirable by enthusiast standards, the 882 (common SBC smog era castings) heads featured both small valves (1.94/1.50) and large 76cc combustion chambers. The heads showed all the classic signs of high mileage, but we weren't concerned, since the heads would be subjected to a complete rebuild (including larger stainless steel valves, in addition to performance porting). Upon final disassembly, we were pleasantly surprised to see the rod and bearings (and therefore the stock cast crank) in decent shape, and cylinder walls free of major scuffing. Basically, it looked like we had a good rebuild candidate for our 365hp build up.

The first step in the was to build a solid foundation. Our four-bolt 350 was taken to L&R Automotive in Sante Fe Springs, California, for the necessary machine work. The block was bored and honed to accept a set of 0.030-over forged JE replacement pistons. The flat-tops featured valve reliefs to accept cams up to 0.525 lift, more than we planned for this adventure. The piston design worked with our 75cc chamber heads (deck surface milled slightly) to produce an 89-octane friendly static compression ratio of 9.1:1. Note this was a far cry from the 11.0:1-plus compression ratios run on the original 365hp motors. L&R Automotive also took the liberty of hot-tanking the block and installing new cam bearings.

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