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Camaro Race Engine - Horsepower!

How do you get big power out of a small-block? Spin it to the moon, Alice.

Photography by Campbell Auto Restoration

302CI Chevy Z/28
Chad Raynal, San Jose, CA
If you haven't noticed, we really dig the late '60s Trans-Am cars, so when we ran across Chad Raynal's '69 Camaro, we had to show you the engine compartment. Chad owns an original '69 Z/28 Camaro that is a documented veteran of the SCCA Trans-Am circuit in May and June 1972, originally raced by Richard Sterbins and later campaigned by William MacFarlane. The car finished 13th in the Lime Rock race in May and then suffered a DNF (did not finish) at Watkins Glen in June 1972. Chad now races the car in the Historic Trans-Am (HTA) series that will be racing in 2009 at Infineon Raceway in Sonoma, California, May 29-31 and the excellent Coronado Classic that is part of Fleet Week in San Diego September 25-27. The HTA series requires all the cars to be period correct as much as possible, which means no modern road race amenities such as G-Force transmissions or electronic data-logging. If you've never seen these cars run, it's worth the trip to get a taste of what it was like in the early days of Trans-Am.

A. Ignition That may look like a stock point-type distributor, but it's actually a very rare, ball bearing, tach-drive distributor with transistorized ignition that was leading edge in 1969. This is a factory distributor more often found in Corvettes and first appeared as early as 1964.

B. The Cross-Ram The centerpiece of the Trans-Am Z/28 engines was the cross-ram induction system developed by GM engineers and then massaged by notable engine tuners such as Smokey Yunick. Note the proper 3941130 casting number and the unmistakable Winters snowflake casting mark. Chad's engine takes a minor liberty with the carburetor main bodies with what look like Holley HP pieces. The original carburetors for the early cross-rams were 595-cfm Holleys with a 4295 Holley list number. Note the early slotted screwdriver bowl screws. Cool.

C. Tech Tip Want to ensure that your dipstick doesn't blow out if crankcase pressure increases? Drill a hole in the dipstick handle and attach a spring.

D. Valve Cover Dimples Chad's engine uses original factory valve covers that have been carefully dimpled for better rocker arm clearance.

E. The Short-block When Chevy decided to get into SCCA Trans-Am racing in 1967, the displacement limit for the big V-8 engines was 5.0 liters or 305 ci. Since Chevy didn't have a 302 engine, it did the next best thing and built a 302 by combining a small-journal 327 4.00-inch-bore block with a forged-steel 283 3.00-inch-stroke crank that instantly became a high-rpm motor with factory 11:1 compression. The factory Z/28 camshaft in those days was the classic Duntov mechanical lifter 30-30 cam, named for its 0.030-inch valve lash spec, but most engines used upgraded cams. Chad's engine is a four-bolt main block with forged 12.5:1-compression pistons assembled by Ted Yamashiro at Top of the Hill Performance Center in Livermore, California. If you look closely just behind the water pump, you may notice a pipe plug that indicates this is probably a newer vintage Bow Tie iron block.

F. Wired You can tell this is a true competition engine compartment if for no other reason than the prodigious use of safety wire around such items as the oil fill cap and the alignment shims for the upper control arms.

G. Welded Early Trans-Am rules required the use of the stock front subframe, so the racers went to the effort of completing all the welds along the length of the subframe for strength.

H. Headers The headers are period-correct Jere Stahl road race pieces with 1 7/8-inch primaries and 3 1/2-inch collectors that feed into oval exhaust pipes with no mufflers.

I. Lubrication Dry-sumps were not part of the deal back in 1969, but wet-sump technology has improved quite a bit in the last 40 years, so Chad's engine uses an Aviaid 10-quart road race pan with the same trapdoor configuration first used on the Penske/Sunoco Camaros, along with this breather vent tank that is connected to both valve covers.

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