On December 21, 1970, my wife and I bought a tired, 82,000-mile, 1962 fuel-injected Corvette. It ran OK, but it wasn't totally original. It sold new in Redding, California. We bought it in Fresno. The fuel injection was missing, the Borg-Warner four-speed transmission and shifter were 1957 issue and the heads were Power Pack 283s.
The trunk lock was inoperative, but when we got it open we found the original 461-X heads (date-coded three weeks ahead of the block) laying in the spare tire well. One had a small crack. The original, wheezing, 327 short-block had a small cast-iron intake manifold. The carb was an AFB mated to an adapter plate. We paid $600. In all, the car was like a pretty girl with a dirty face. It was a car that had been driven, but not serviced.
You can almost "see" the high...
You can almost "see" the high nickel in this 159-pound, 1962 Corvette 327 block. The cylinders got a 0.030-inch overbore, the bumpy decks needed 0.030-inch milled off and the crankshaft align-bore needed a few passes.
Inside of a week, we cleaned all the corroded electrical wiring, replaced the chattering clutch assembly, tightened the pinion nut and adjusted the steering box free-play. In top shape back then this car was worth $2,000.
We then replaced the tired engine with an almost new, 1967 350hp 327 Corvette long-block that had set us back a whopping $150. The rest of the '62 remained mint and original, including the interior (less carpets), front and rear bumpers, emblems and body chrome. We put the original 327 short-block on a stand and the 461-X heads in GM head boxes.
In mid-1976, we returned to California and I entered the car magazine business at Popular Hot Rodding and Super Chevy. Both happily consumed most of my waking hours for the next 19-3/4 years. From mid-1976 all the way to today, the '62 was mostly garaged. We did buy a 1962 fuel injection unit that had previously been on Marv Ripes' 1968 Stock Eliminator world champion '57 Corvette, but its nozzle lines kept plugging up from sitting.
Valley Head Service machinist...
Valley Head Service machinist Alex Pulido put our replacement crankshaft through its paces. After weighing each piston, connecting rod, piston ring set and bearings, he installed identical weight "bob weights" to the crankshaft to check its balance. This is a time-consuming process.
Fast forward to 1984, when the Vette was featured in Super Chevy as "Patti's Daily Driver." We hopped up the '67 327, added Schiefer 5.13 gears, a huge cam, S&S slapper bars off my old '66 L79 Nova and Firestone Drag 500 slicks and ran high 11s at 112 mph. It was too radical to drive around town so it was parked. Again. Its chassis, unbelievably, has never been washed-not to this very day. Except for a corroded battery tray, everything throughout is rust-free and original.
When lead additive was taken out of pump gas in 1972, I began thinking how I was going to one day rebuild the car's original 327 fuel-injected engine. I drag raced in Stock and Modified Eliminator, winning 107 of 121 final rounds, but in the mid-1970s, we were also members of the NCRS (National Corvette Restorers Society). So, we were mentally caught in a perplexing dilemma. Do we rebuild to "factory-stock" with an outdated, low lift, Duntov solid lifter cam and 11.25:1 compression ratio, and keep all of our purist friends and octane booster folks happy? Or, do we lower the compression for today's pump gas and increase the camshaft profile in order to hopefully increase performance?
For your review, here's a...
For your review, here's a close-up of a bob weight. A bubble balancer is used to correctly position each assembly.
After many years of contemplation, and mental finger-tapping, we finally decided on the latter. Here's why: Hoping to keep the 327's power output near its advertised rating of 360 at 6,200 rpm, we bought a set of 0.030-inch oversize, 10.0:1 compression Speed-Pro hypereutectic pistons (#H660CP) over the Internet. For a camshaft, we special-ordered a grind that Zora Arkus-Duntov casually talked about over dinner in 1986. We thought it would be a nice tribute to him if we used a cam with "his" specs (0.480-inch lift, 280 duration and a 106 or 108 lobe separation angle). He did not specify hydraulic or mechanical lifters. But Zora was a mechanical lifter sort of guy. No wimpy hydraulics for him.
Enter Joe Sherman Racing EnginesNow the plot thickens. Long time friend Joe Sherman stepped right into the mix when we asked for his advice. He thought that if Zora were standing here today he'd much rather approve the new Comp Cams "Thumper" roller camshaft with Comp Cams "Beehive" valve springs (0.510 intake/0.490 exhaust, 280 duration, 107 lobe separation angle). Gee, we thought, Zora's words to us were 20 years ago. We thought Sherman was right. After all, he is one of today's best engine power-makers. So, the $65 "Zora" cam we special-ordered is now headed for our hot '70 383, four-speed Malibu.
At the beginning, our crankshaft...
At the beginning, our crankshaft was 12 grams out of balance (22 grams equals one ounce). When Alex Pulido was done, the crankshaft was 1/2-gram from being perfect. When you get down to a few grams or less, the engine never "feels" it or reacts negatively to it.
Larry Ofria at Valley Head Service gladly agreed to spec out the original 327 bare block and also repair and rebuild the 461-X heads. Every blueprinting engine spec was performed. Minimal crankshaft web align-boring was needed. The block's decks were described as "lumpy," so 0.030-inch was milled off-including much of the stamped numbers. But we wrote them down and will re-stamp them deeper into the block some day.
Ironically, the milling still left 0.020-inch above piston top dead center. The eight cylinders were bored 0.027-inch and then finish-honed the remaining 0.003-inch. This left a Speed-Pro-recommended 0.015-inch piston-to-wall clearance. We like Speed-Pro hypereutectic pistons (they first engineered them in the early 1980s) because they are said to be as strong as a forged piston and have the expansion rate of a cast piston (very little). So, the piston rings will seal better and there will be no piston slap noise.