LEARN­ING BY DO­ING

How a trou­ble­some buildup of a Pro Street ’68 Ca­maro ended hap­pily ever af­ter

Chevy High Performance - - Contents - TEXT & PHO­TOS: Steve Tem­ple

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.

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