LEARNING BY DOING
How a troublesome buildup of a Pro Street ’68 Camaro ended happily ever after
There’s a first time for everything, like riding a bike or diving into the deep end. But just as you might skin a knee from a fall or cough up some pool water, it wasn’t all easy-peasy for Bren Manke working on his ’68 Camaro.
“This was the first car build I had ever done,” he admits. “I built the entire thing, including all the engine assembly, rollcage fabrication, suspension work, wiring, and just about everything else, in my two-car garage.”
Fortunately, Bren is mechanically inclined and had some
previous experience working on snowmobiles with his dad, Bill. And he had one big motivation: to build this car with the sole intent of making it go really fast.
That’s a familiar line to Chevy High
Performance readers. Making it happen is a whole ’nuther story, though. Fortunately, when he found the car on a Craigslist ad as a rolling chassis, it had very little rust. “But it was pretty much just a shell,” he admits.
While his idea initially was to build a Pro Touring car, his focus shifted after attending the NHRA Sonoma Nationals and watching some cool old drag cars tearing up the track. So he switched horses in midstream and went the Pro Street route instead.
“The only problem was that I had already mini-tubbed the car,” he notes. “So I got the absolute biggest tires I could fit into the wheelwells without doing fullsize tubs.”
He also welded in some subframe connectors and bolted on Competition Engineering Slide-A-Link traction bars, secured to a 3.70 Ford 9-inch with Moser 33-spline forged axles. To further minimize axlewrap, Detroit Speed supplied 3-inch drop-leaf springs and shocks.
This setup was for putting some serious power to the pavement—about 750 horses at 15 psi from a 383 smallblock topped with a Weiand 6-71 blower. All good in theory, but he encountered a few bumps in the road along the way. The first one happened while testing the engine right after he had gotten the Weiand blower installed.
“I went to my favorite testing spot and floored it,” he relates. “Well, the throttle linkage that hooked to the carburetor wasn’t adjusted right and got stuck against the side of the blower, keeping it at full throttle. I was getting really close to 140 mph when I shut the ignition off.” As a result, the engine backfired super hard, which in turn bent the crankshaft. He was able to limp it home and ended up pulling the engine and installing a new crank.
The next challenge was a more involved technical issue, as the engine ran too hot. After months of fighting overheating issues he determined the problem was caused by the blower being over-driven too much.
“I was achieving the boost levels I wanted, but the extra load during idle and cruising caused it to overheat.” And that was after trying all sorts of fixes, such as installing a huge radiator that barely fit between the framerails, adding water wetter, a high-flow 55-gpm electric water pump, and dual shrouded electric fans, plus adjusting the timing, changing the jetting—everything.
He eventually went with a Whipple W200R twin-screw supercharger instead, which has a bypass valve to bleed off boost at slow speeds. Even so, he replaced the plastic butterfly-style valve with a turbo blow-off unit. Why the switch? “Because of the aesthetics and the fact I can calibrate the amount of vacuum needed to open it by using different tension springs,” Bren explains.
Drawing on his snowmobile experience, he also designed a
water-to-air intercooler to adapt it to his existing 6-71 intake. That involved drawing up several designs and fine-tuning through trial and error (just as he did on the rest of the project).
Assembled by Bren, with some help from his father, the innards of the engine provided by CNC Motorsports include Eagle forged rods and a crank with a 3.750-inch stroke in a 0.030-overbore of 4.030 inches, slinging JE forged pistons with an 8.8:1 compression ratio. AFR 220 heads run Scorpion 1.5:1 rockers. Filtering the air into a Pro Systems SV1 carb is a K&N element with a custom scoop.
Downstream from the block are Schoenfeld headers (1 7/8 to 1 3/4-inches), dumping into a 3-inch custom X-pipe and dual mufflers. Backing up the mill is a TCI Auto Turbo 350, actuated by a B&M shifter and fitted with a trans brake.
Another scary surprise came when Bren was trying out a new electric fuel pump. He had it operating for a while without having the car running. So how did things get a little weird?
“Well, unknown to me when I had installed the fittings on the pump, a small metal shaving made its way into the carburetor and kept the needle and seat open, flooding the motor extremely bad (like, hydraulic the motor bad),” he relates. Bren decided to pull the spark plugs and crank the engine to clear the gas out but forgot to unhook the coil.
“When I hit the key something sparked and ignited the gas that came out of the cylinders, and before I knew it I had three-foot flames shooting out of the engine bay,” he recalls with wince. Fortunately, he grabbed a fire extinguisher and put it out pretty fast— but not before it burned up the majority of the wiring around the engine.
“We also had a heck of a time getting the matte finish to come out right,” Bren admits. “We ended up spraying, sanding, and respraying the entire car because when the matte finish would begin to dry, random striping would appear, the worst of which were on the flat surfaces such as the roof and decklid.” That’s when he decided to go with the two-tone flat/matte finish.
Despite all the hurdles and hiccups, this build had a good ending, as he and his bride, Aggie, did a smoky burnout at their wedding reception. All told, after three years of overcoming various challenges, “This car was an absolute blast to build and one heck of a learning curve.”
And they lived happily ever after.