When Ken Adrianse's '65 convertible was first featured on the pages of VETTE in September 1996 ("Drop-Top FUELIE," pg. 38). It was "just" another beautifully restored, one-owner mid-year roadster with a 375hp factory fuel-injected 327 small-block.
My how things change! The '65 is still every bit as gorgeous as it was seven-plus years ago, and Ken is still the Vette's only owner-but it's no longer totally stock. Ken, a now-retired school teacher living in Burbank, California, with his wife Ann, has been careful for 38 years to personalize his Vette without cobbling it up. Now he's truly taken it to another level by adapting a Vortech supercharger onto the NCRS-type Vette. Ken's been no stranger to tinkering with his Corvette over the years, but engineering a blower onto the Rochester mechanical fuel-injection system (without cutting or modifying any original parts!) has got to be his crowning achievement with the car.
In April of 1965, while Ken was completing his last semester of studies at Western Michigan University, he ordered himself a brand-new Corvette convertible from C. Bell Chevrolet in Grand Rapids, Michigan. Ken indulged in the typical options for his new sports car, like power brakes, Posi-traction, a close-ratio four-speed, tinted glass, and an AM/FM radio. But as a soon-to-be college grad on a relatively slim budget, Ken could not yet afford the premium option he wanted so much: fuel injection. Instead, Ken settled for a carbureted 327/300hp motor, one step up from the standard 327/250hp engine.
Ken took delivery of his new convertible on June 30, 1965 and, "I can vividly remember watching the salesman drive the car down a ramp and park it on the street in front of the showroom," he tells us. "It was a dream come true!" In August, Ken moved to Southern California to begin his teaching career. "I made the trip to California in about four days with all my possessions in the Vette-including a two-drawer file cabinet. Burbank has been my home ever since arriving in 1965."
Ken settled into his new home, new career, and new Corvette quite nicely, but he never forgot about the fuel injection. "I was fascinated by the various magazine articles back then that featured the mechanical F.I. unit as the ultimate induction system." In the late '60s, Ken went hunting for an F.I. system and finally heard that Dick Guldstrand had a complete unit for sale. The induction system had been used on one of Dick's race cars. "After one visit to his shop in Culver City [California] to look at this unit," Ken recalls, "I was hooked. Dick had completely restored every piece of the system to look like new." At a price of $275 for the complete F.I. unit, less air cleaner and "S" tube (roughly half of the cost for an RPO L84 in 1965), Ken couldn't go wrong.
About two weeks later, Ken had installed the fuel-injection system, along with all the other components (including pistons, camshaft, lifters, exhaust manifolds...) necessary to create a factory-spec 327/375hp Fuelie. It took several months, however, to work out all the little gremlins. Ken eventually realized that Dick had modified the injector nozzles for his racing application. A new set of nozzles made the car run perfect. Ken was now extremely satisfied with his toy.
Ken continued to use the '65 as his daily driver for 15 years. "After our daughter was born in 1978, it didn't get much use for several years." Ken pulled the mid-year out of mothballs in August 1988 to begin restoring it. "Little did I know that this would be a huge undertaking that would require six years and 3,800 hours to complete!," he admits without regret. After a complete frame-off restoration where all the work-save for paint and engine machining-was done in his garage, Ken had himself a fantastic "Sunday driver."
For 10 years, Ken was happy cruising around in his stock roadster, attending six to eight car shows a year, and collecting his "share of trophies." When Ken retired from the Los Angeles County Office of Education in April 2001, he threw down the gauntlet. "I wanted to do something unique to my dream car. Because superchargers were becoming popular on modern EFI engines, installing one on my mechanical Rochester F.I. seemed like a challenge I couldn't resist...the 327 small-block was rated at 375hp in 1965, so why not add five or six pounds of boost to increase that number by 45 or 50 percent? With the Rochester design utilizing an air meter, fuel meter, and plenum to vent the air into the cylinders, it appeared to be a natural fit for a modern centrifugal supercharger." Ken invested many hours researching the prospect, but couldn't find anyone who had successfully attempted such a feat.
With the Rochester fuel injection having been around since 1957, it seemed logical that someone at some time would have toyed with the concept. "I started by asking fellow gear-heads in Southern California, but few had any working knowledge of how the mechanical F.I. system worked, let alone trying to supercharge one," Ken tells us. Next he posed the question to several colleagues in his local NCRS chapter, but again to no avail. The Internet provided Ken with some answers to his blower questions, but the only luck so far was for carbureted motors. Ken found a catalog collector in the United Kingdom who sent him pictures from Paxton illustrating all the parts and pieces necessary to supercharge a carbureted '56 Corvette. But, again, the McCullough blower was designed for dual four-barrel carbs.
After months of searching but finding no answers, Ken almost gave up. Then he remembered a conversation he had several years before with Tom Lee of Lee Power Steering in Sun Valley, California, about his use of a Rochester system. Ken contacted him and was elated to learn that Tom had indeed designed a similar blower system on a '58 F.I. Corvette. He'd had many problems to overcome, particularly because he'd forced the boost through the air meter and that caused issues with the vacuum-controlled main diaphragm that determines fuel mixture. It was very fast in the end, but Tom hadn't saved any records or pictures of his achievement.
Talking with Tom encouraged Ken to continue his foray; so the search continued. Then another name from the past surfaced, and Ken called up Chris Wichersham of Corvette Specialty Parts in Monrovia, California. "In a call to Chris in early October 2002, I heard the words I'd been looking for: 'Sure, it can be done!' So we set up a lunch date to work out the design details. After two hours of lunch and discussion, we had solved most of the inherent design problems."
Chris and Ken decided the key would be to mount the air meter to the inlet of the supercharger, which would maintain the vacuum signal necessary to regulate the flow of fuel to the injectors.
Now that Ken was fairly convinced that it was doable, he went blower shopping. "Shawn Roberts of Extreme Automotive in Canoga Park, California, referred me to Todd Armstrong, CEO at Vortech Engineering, who suggested that I go to their facility to see if one of [their] head units would fit." He did so in November, and spent an hour with John Snee and Chris Wahley of Vortech test-fitting several different compressors in the Vette's limited space, and they finally opted for a V-2 SQ S-Trim supercharger. "Todd offered to let me borrow an old compressor unit to use as a mockup, and I gladly accepted his offer!"
Ken's installation process began the very next day, and he took extreme precautions to preserve the originality of the Corvette. "Even though it wasn't an original Fuelie, I did not want to modify, cut, or destroy any of the original parts like inner fender panels, underside of the hood, or any engine part. I was committed to fabricating all of the necessary parts using existing bolt patterns in the block or on the F.I. system, and I was successful in all but one area." Other than being unable to avoid tapping a 1/4-inch hole in the stock oil pan for a return oil line, Ken kept his word. Between November 23, 2002 and May 3, 2003, Ken invested 472 hours in the project!
The installation was a rousing success, meshing new technology to old without compromising either. Ken says, "I was surprised that drivability was just like it was without the supercharger, except for that sweet whine or whistle only a supercharger can provide." Ken notes that Vortech's SQ designation stands for "Super Quiet," referring to its helically-cut gears. As for performance, well, it really performs. Ken estimates 475-plus rwhp at 6,000 rpm and 500 lb-ft torqe at 4,800 rmp. And he plans to verify these numbers soon when he dials in the motor's tuning on a chassis dynamometer.
Yup. Ken's defied the odds and guaranteed that his '65 Fuelie convertible is more than just another pretty face!
How He Did It
Though the Rochester mechanical fuel-injection system has been around since the '57 model year, and approximately 13,000 Corvettes were equipped with F.I. induction from '57-65, surprisingly few people have attempted to supercharge one, and even fewer have succeeded. The installation that Ken performed on his '65 Fuelie is marvelous. It looks natural under the mid-year hood and runs perfectly, and he managed to keep 99.9 percent of his commitment to not modify any original pieces.
Luckily for us, Ken carefully documented the process he took so we could share it with you.
Once Ken had estimated the ideal location for the Vortech supercharger under the hood, he began designing the mounting plates. After cutting-out and test-fitting numerous card templates, Ken transferred his design and milled the final bracketry from a 3/8-inch-thick 6061 aluminum plate. Because the original cylinder heads do not have accessory bolt holes, Ken had to find another way to attach the main mounting plate to the engine block. Bob Endress of Vortech Engineering suggested he use the left-side water pump bolt pattern. This design worked perfectly. However, Ken had to mill 3/8-inch off the left-side water pump outlet to compensate for the plate thickness. Ken decided to replace the stock water pump with an Edelbrock aluminum "super-cooling" water pump.
Because the air meter was to be moved from the F.I. plenum to the supercharger inlet, it was necessary to fabricate an air meter adapter rings. Both adapters were turned from 6061 billet aluminum stock.
A second mounting plate is bolted to the compressor, which is then bolted to the main mounting plate. Ken's first design did not allow for adequate clearance between the exhaust manifold and the compressor volute, so he had to start all over-as he did on numerous other occasions.
The next step was to mount the compressor head unit and plate to the engine block-mounting plate. Ken had to first rotate a V-belt type pulley (as all current pulleys are serpentine design) so that the supercharger pulley could be aligned with the other pulleys. The size of this pulley also determines the impeller speed-a critical aspect of supercharger boost-so Ken opted for a 3.70-inch pulley to keep the impeller speed below 42,000 rpm at 6,000 engine rpm. The pulley was then attached to the supercharger and lined up with the crank and water pump pulleys to determine the space needed between the two mounting plates. Three stainless steel spacers were then turned for this purpose. To add rigidity to main the mounting plate, a support was added to the front bolt of the F.I. base plate-another support at the bottom to the left-side motor mount-and for good measure, another brace to an adapter between the thermostat housing and intake manifold.
After the air meter was attached to the supercharger inlet using a 3 1/2-inch silicone connector and T-bolt clamps, it was time to design a new throttle linkage system. The best solution ended up being a 4-foot throttle cable unit from Lokar Performance Products. Attaching the cable to the air meter was not difficult, however, attaching the other end to the original F.I. bellcrank proved much trickier. The challenge was to design a second bellcrank that pulled the cable to open the throttle, as opposed to the original rigid linkage that pushed the throttle plate open.
With the air meter secured to the supercharger inlet, it was obvious that a heat shield would need to be fabricated around the exhaust manifold. Ken removed the air meter to enable him to design a template that would be attached to the spark-plug shield brackets on the bottom and to the front valve cover screw on the top. The template design was transferred to a piece of thin sheetmetal to see how it would fit. After a number of trial bends, this revised pattern was traced onto 18-gauge sheet steel and folded into shape. He used spot-welds to hold the various bends and angles in place.
After the air meter was adapted to the supercharger inlet and the throttle cable installed, Ken had to design an inlet for the air-meter-to-air filter. He started with a '63 air meter adapter and made a template to rotate the air-filter unit under the left fender. Brady Sheet Metal of Burbank California, then replicated the template using 18-gauge sheetmetal. A K&N air filter, PN RF-1008, was clamped to the 4 1/2-inch air inlet.
Next, Ken next needed a 3-inch aluminum elbow for connecting the compressor discharge to the F.I. plenum inlet. Because of limited space, Ken needed a short radius that would require mandrel-bending equipment. He found that most shops that do this type of work are limited to smaller-diameter tubing so, after several months of searching, he was referred to Josh Deeds at Innovative Turbo Systems in Simi Valley, CA. Josh was able to mandrel-bend a 90-degree elbow using .065 aluminum tubing within a few days.
With the major components in place, it was time to resolve the vacuum system problems related to boost in the intake system. Four circuits that relied on vacuum were modified with check valves to prevent internal or external problems from boost pressure. They include the crankcase vent at the F.I. plenum, the power-brake booster, the distributor vacuum advance, and the fuel bowl vent into the F.I. plenum. Each line was fitted with a check valve from Smart Products, Inc. in San Jose, CA.
The Rochester F.I. idle circuit requires air plumbed from the air meter to four nozzle blocks (that hold the nozzles in place) at each corner of the plenum. Because the air meter was moved some distance from the lines used for this purpose, a small K&N air filter, PN 62-1360, was used to filter the air at idle speeds. The 3/4-inch opening at the bottom of the air meter was capped with a rubber cover.
The amount of fuel sent to each nozzle is determined by a vacuum control signal generated by "a highly efficient annular venturi between the air-meter body and a diffuser cone" in the air-meter assembly (Corvette Shop Manual, pgs. 6M-34). Ken designed and fabricated a new line using 1/4-inch steel tubing. On the air-meter end, a 1/4-inch "O" ring is used to seal the line, and a 1/4-inch compression nut and 90-degree fitting are used at the fuel meter end. If this vacuum line has the smallest leak, the main fuel-control diaphragm will not function properly and drivability will be erratic. Another 1/2-inch line runs between fuel-meter main diaphragm housing and the air-meter adapter to vent gas fumes. This piece was fabricated from 1/2-inch aluminum tubing and connected to the original tubing.
The Vortech supercharger uses engine oil to lubricate the gears that turn the impeller. On current small-block Chevy applications, Vortech recommends removing a 1/4-inch plug in the block located above the oil filter for the best source of filtered oil. Ken found that his '65 327 block was manufactured with a welch plug that would be difficult to remove, let alone tapping the block with a 1/4-inch NPT thread. He resolved this problem by inserting a 1/8-inch Tee in the line that is used for the oil-pressure gauge in the dash cluster. The fit is very close to other components, but it made a very clean installation.
A return oil line is plumbed from the bottom of the supercharger gear case to the oil pan. Ken attempted to find an aftermarket oil pan to avoid cutting a hole in the original part, but found that current S.B.C. aftermarket pans are not designed for this vehicle. He finally gave in and cut a hole in the pan and welded a 1/4-inch NPT fitting in the left-front side. This was the only original part on the Vette that Ken had to modify in anyway.
With the induction system complete, Ken turned his attention to driving the supercharger. Ken used a 1/2-inch Gates V-belt, PN 9555, that is 55 7/8-inch long to drive the blower pulley refered to in step 3. To keep the belt tight, he used an idler pulley (arrow) and eccentric as recommended by Frank Mirate at Burbank Auto Parts. This idler runs on the flat side of the V-belt and was originally used on mid-'80s Chrysler products. The upper radiator hose had to be relocated because the V-belt driving the compressor was in the way. This was accomplished by using an aftermarket thermostat housing outlet and relocating the water inlet on the radiator. After an hour or so of searching, Ken found a molded upper radiator hose that could be cut to fit exactly.
Two vent lines remained to be fabricated. The first involved slightly bending a piece of 1-inch (outside diameter) tubing to connect the air-meter adapter to the crankcase vent, which is next to the distributor at the rear of the block. The second item was a 1/4-inch line from the exhaust manifold that provides heated air to the automatic choke.
Once all of the necessary brackets, braces, tubes, etc. were fabricated and the entire system assembled, Ken disassembled all of parts to send them to a plating shop. In the end, 50 pieces had been custom-made for this project, and Ken had scrapped 25 more pieces in the process of getting everything right!