Highland technician Louie Rumbaugh performed the conversion in about two hours from start to finish. While the car was apart, the technicians at Highland also installed an Isky TH-55 cam (260° duration, 38° overlap, .430-inch valve lift) with Isky springs, aluminum retainers, Raymond special valve stem oil seals, a 4.10 rearend to replace the stock 3.90 unit (that was the lowest gear we could get at the time) and a lightweight flywheel, clutch and pressure plate assembly. The stock Corolla flywheel, clutch and pressure plate assembly weighs over 40 pounds, which is great for low-end torque, but the excess weight robs horsepower at the top end. The lightweight units With a sintered metallic clutch disc, available from Dean Lowry at Deano’s Competition Compacts in Santa Ana, California, would give back some of that valuable horsepower, we hoped.
Even with the super-wide J.C. Penney’s tires, the suspension needed some perking up. We started with a set of Koni adjustable shocks from their U.S. importer, Kensington Products Corporation. The Corolla front shocks are part No. 82P 1743, and the rears are part No. BOA 1986. We’d like to thank Kensington for their efforts above and beyond the call of duty in getting us these shocks, since after we requested the units, the Koni people discovered that there wasn’t a single set of Corolla front shocks to be had anywhere in this country. They immediately sent a telegram to one of their representatives in Holland, who personally hand-carried the units on his return trip to the States. That’s service! Thanks, Koni.
With everything put back together and the crankcase filled with Pennzoil 20W-40 Racing Oil, we set out for our first ride around the block. It proved to be a bit disappointing. While the car ran a lot better, the clutch just didn’t feel right-a premonition of future troubles. Except for the clutch, we were fairly pleased, but the first trip to the strip didn’t bear out our seat-of-the-pants impressions. Uncorking the headers, we recorded a yawning 17.10 at 78.21 mph, an increase of only .1-second. Frankly, we had expected more, but the clutch was starting to slip, causing a loss of both e. t. and mph.
After experimenting with some headers that just didn’t get the job done, we replaced them with a ’71 Corolla cast iron exhaust manifold and a Dean Lowry exhaust system. The stock ’71 manifold is better than the ’72 unit and better than most headers because it is a 4-into-2 rotational design. The Lowry exhaust system has been designed to supplement this manifold, as it extends the two exhausts for about 18 inches and then funnels them into a single 1 3/4 inch-constant-diameter pipe running the full length of the car. This system is much like a tri- Y header arrangement, but the use of the cast-iron manifold prevents the “coffee can full of rocks” sound that comes with tubular headers. It was just the ticket, as the Corolla improved by a full half-second and 2 mph over the stock setup and by .7-second over some of the nonrotational headers we tried. (On the drag strip, the exhaust pipe and low-restriction muffler were replaced by a VW-type conical stinger that Dean developed especially for use with this system.) Needless to say, the system works, and it’s much quieter than most street performance exhaust systems we’ve tried.
Meanwhile, we were making some other modifications designed to aid both handling and appearance of our Project Car. Inside we added a black foam-rim steering wheel from Superior Industries. On the exterior, we added a super-hard plastic front spoiler from Kastner-Brophy, a Triumph racing firm headed by former Triumph Competition Director Kas Kastner that’s recently started producing goodies for Toyotas. Kas offers engine pieces, suspension parts and spoilers for both the street and track. The street units like ours are sturdier in order to survive the punishment of drivers like Hot Rod Editor Terry Cook, who at last count had destroyed two other spoilers but never even dinged the Kastner-Brophy model. With a list price of $38, this unit is definitely a bargain. The purpose of such spoilers is to reduce the front-end lift at speed and provide added down-force, but it looks plenty neat as well.
Because we were still encountering the problem of the tires being too big for the wheelwells, we decided that a change was in order. We selected a set of Concorde radial tires (AR70x13), since radials are said to be the tires of the future. We can certainly understand why, after trying them out on the OCIR skid pad! With the Concordes mounted on our trick Appliance Plating Wire Mag wheels and using a slightly larger front sway bar (.875-inch diameter replacing the stock .625-inch bar), we lowered the cornering time to an incredible 12.8 seconds, or equal to .74 G. The rest of the suspension was still stone-stock except for the Koni shocks, so we felt there was still more room for improvement. As for the Konis, they provided a tremendous improvement in handling “feel” while giving the slightly firmer ride that the Corolla needed. As good as they are, however, the effect of shock absorbers does not show up on the skid pad, because the skid-pad performance is only a measure of a car’s steady-state cornering ability rather than a measure of its transient, or side-to-side, suspension response. It’s the side-to-side handling ability on a road race course or a twisty back road that gives an indication of how well your shocks are working. On the skid pad, shocks take a set position, depending on the suspension deflection, and provide no effect whatsoever. What we’re trying to say is that we could feel the marked improvement provided by the Konis, but the only way to measure this accurately is on a race course that includes left turns, right turns and switchbacks.
Meanwhile, back at the drag strip, we had decided that some more carburetion was necessary to take advantage of the Isky earn and 4.10 rear. We contacted Harold Graves at Man-A-Fre Induction in nearby Northridge, California. Harold is a Rochester carb expert who has developed many systems for VW s, Toyota Land Cruisers and several other different cars, using the venerable Rochester 2-GC two-barrel unit. It was just our luck that Harold was indeed developing a carb for the Toyota hemi and was looking for someone to “try it out.” The Man-A-Fre kit, retailing for about $56, includes a 500-cfm Rochester, an adapter plate to bolt it to the stock manifold, throttle linkage and a neat chrome air cleaner. Harold also turned us on to a neat dress-up trick for Toyotas. Both the manifold and the valve cover on this engine are aluminum. So a simple $25 polish job makes them look like they’d been chromed.
The Man-A-Fre setup not only looked impressive but worked quite impressively as well. Our Corolla was now screaming through the quarter-mile in 16.45 seconds at almost 83 mph. We now had more than enough power to break the rearend loose, so we started searching for some skins to get us out of the gate. We soon discovered, however, that drag slicks do not come in 13-inch sizes, so we used the next best thing: a set of super-wide Goodyears that had been recapped with a really sticky compound by the Hurst Tire Company in San Diego, California. Along with the gummies, we also decided to try some really exotic carburetion that Dean “just happened to have lying around the shop someplace.” It was a pair of two-barrel Solex side-draft carbs mounted on a straight-through manifold made by PBS Engineering in Garden Grove, California. Any single-carb setup on a four-cylinder engine leaves a bit to be desired when it comes to distribution of the mixture to the cylinders, so we figured that the multi-carb arrangement would be a great improvement, since it’s essentially a single carb for each cylinder. You can’t get much better distribution than that. That combination sure did the job, rocketing the Corolla to a new best of 16.11 at 83.56 mph. The car really hooked up, coming out of the gate at five grand, and put out the power all the way up to the 7200-rpm redline. With the small-diameter tires and the 4.10, however, we were only able to use three gears, motoring through the eyes near the top of third. Now that we had the ultimate carbs and more than adequate exhaust, it was time for a bigger bumpstick and some head work.
Our quest for horsepower led us to Norris Cams in Van Nuys, California. They’re the same people who provide the cams for Clayton Harris’ low-6-second passes down the strip. Norris has three different grinds available for the Toyota hemi, and rather than be greedy for power that would make our car totally unstreetable, we chose the intermediate, or street/strip, grind. At the same time the cam was being installed, Dean took the aluminum hemi head up to Kay Sissell’s Head Porting facility in EI Monte, California. A little time on the flow bench and some judicious work with the grinder resulted in a head with the flow rate increased by almost 30 percent. We couldn’t wait to get back to the strip.
In addition to the camshaft, Norris also provided a set of their chrome moly push rods, double valve springs with dampeners and super-trick titanium valve spring retainers. (This last item is definitely worthwhile if you’re building an all-out Toyota racer, but the rather high cost of $44 a set puts them out of reach for street/strip fans. If you’re building a street/strip Toyota, you’ll be better off with the Norris hard-anodized aluminum retainers at $16 a set.) Everything went back together again with no problems, the crankcase was filled with fresh oil, a Fram oil filter was installed, and off we went to OCIR.
The results were almost too good to be true: 15.60 at 86.22 mph. Wow! Into the 15s with only 97 cubes! Before we were finished for the day, we managed to squeeze out an almost unbelievable 15.46 at 86.96 mph. What a ride. . . and we still had the stock 8.5:1 compression ratio pistons and the 4.10 rear. All was not gravy, however, as that sintered metallic clutch disc started acting up again.
Just as we were getting ready for our final assault on the drag strip, a brand new Offenhauser Dual-Port manifold for the Toyota hemi had just become available, so we thought we’d give it a try. Since this manifold must be used with a two-stage progressive carburetor, we mounted the only one we could get our hands on – the stock carb – onto the Dual-Port and headed for the strip. We must admit that this wasn’t really a fair test, but our brief exposure to the Offy led us to believe that the hot setup for a street-driven Toyota would be this manifold, a little bit of cam, the Dean Lowry exhaust system and perhaps a larger-than-stock two-stage progressive carb like the ones found on some other Toyota models. And with some work on the jetting, we think that this setup would be emission-legal as well.
In preparation for our final day of strip-testing, we managed to obtain a 4.37 gear and put an end to the clutch problems once and for all by brooming the sintered metallic disc and replacing it with the stock clutch disc. Everything worked beyond our wildest dreams, as the clocks stopped at an incredible 15.16 seconds and 89.37 mph. That was an increase of almost three full seconds and 16 mph over the stocker, and the car was still streetable and delivering 20-25 mpg with the Solex carbs. At the same time, we recorded our best-ever performance on the skid pad as the result of a trip to a brand-new Toyota parts manufacturer, The Toy Store in Culver City.
The Toy Store folk have a long history with performance machinery, having built and raced some of the fastest BMW and Porsche sedans in SCCA racing. Among other things, The Toy Store handles all the fine Norris products, has some lightweight forged 11.5:1 .040-inch oversize racing pistons for the Corolla, and has developed a number of different suspension goodies. These last items were the most interesting to us because we knew that the suspension needed help in order to make this a really fun little car. Stu Haggart, their chief engineer, installed a set of somewhat stiffer lowering springs at the front and lowering blocks and a Panhard rod at the back. This rod, which retails for only $19.95, was designed by Stu to tighten the rear suspension and prevent the side-to-side movement of the body relative to the rear axle in hard cornering or in crosswinds on the highway. One end bolts to the floor and the other bolts to the shock absorber mounting pad, thus providing positive lateral location of the rear axle similar to the Watts linkage setup used on many race cars. The lowering springs and blocks, of course, provide a lower center of gravity, resulting in drastically improved handling. Together, the Toy Store items lowered the Project Car by a full inch and gave the suspension a much better and tighter “feel.” On the skid pad, the results were even better than we expected. Turning counterclockwise, always the faster direction because the driver’s weight is on the inside, we lowered the time to 12.6 seconds for our ultimate lateral acceleration of .770 G. But turning clockwise, the direction in which our Corolla has always picked up the inside rear wheel, we cut a full .4 second off the cornering time, as the inside rear wheel stayed glued to the pavement. Almost all of the excess body lean was gone and ‘the overall handling was remarkably improved.
We still had not attempted some well-known methods of picking up horsepower, like the installation of some 11:1 Jahns pistons that were available to us, or the use of the ultimate strip-only Norris camshaft. We were very tempted to try these items, but time was running short and we decided that our 15-second Toyota was still very streetable. With the high-compression pistons and super cam, our Project Car would be too much a racer and not enough a street machine.
And besides, with the lowering kit, radial tires and quiet exhaust system, this car was really a lot of fun to drive. We had created exactly what we set out to do: a fine-performing, fine-handling and fine-looking Toyota Corolla 1600 Coupe. We’d like to give special thanks to Dean Lowry and John Johnston of Deano’s Competition Compacts for the enormous amount of help they provided. We’d also like to thank the able crew at Highland Toyota for their efforts. Without these people we couldn’t have done it. And if you see a trick red Toyota running around the streets of Los Angeles, don’t try to chase it . . . you just might get your doors blown off!