Here goes the scoop on my '80:
It started out as a stock 1980 L48 4-speed with 3.08 posi. The motor, exhaust and ignition have since been redone. The motor is a new unit from Auto Center in Dallas Texas. It is a new 4-bolt block, forged rods, cast aluminum pistons, L98 aluminum Corvette heads, 9.5:1 compression. Intake is an Edlebrock Performer EGR. Carb is a Carburetor Shop Stage-II QuadrJet. On the factory exhaust, minus the catalytic, the car turned a best of 14.79, averaging about 14.89. The next major modifications made including a whole new exhaust (Blackjack AK5000 headers, 2.5" pipes, single 3" catalytic, DynoMax Super Turbos), a new iginition (Performance Distributors Street/Strip HEI), reconnecting the factory dual snorkel intake, and adding a K&N. Best e.t. dropped to a 14.22, averaging in around 14.29.
According to the AutoCenter literature, the motor is rated 300hp and 350 ft-lbs. The cam is a dual pattern cam (.442"/.465" lift, 288/298 duration, 112 degrees spread). It idles very well with high vacuum (near 20"). I run it to 5500rpms between shifts. It consumes some oil, but nothing out of the ordinary for a small block. With a stock '80 L48 running the quarter in the high-15s, I've added about 110hp and dropped nearly 1.5 seconds off my time! This motor has also seen four 15-hour at-a-time road trips on the highway without any complaints and with decent mileage.
My recommendations for carbureted vehicles:
The engine is a 417 CI small block Chevy, which was created from a 2-bolt 400 block bored .030 over and outfitted with a special Speed-O-Motive offset-ground crank. I deburred everything and installed oil-drainback filters, mounted up a Melling high volume oil pump, installed Clevite (Michigan) 77 bearings, and slopped on lots of sealant to keep the leaks at a minimum.
I bought Dart II iron heads and put a hundred or so hours (some of which was learning time) into porting and polishing them. The compression ratio works out to about 10.5:1, which seems to be just below the practical detonation limit for iron heads and 93 octane premium. The pistons are Arias forged, and the cam is an Iskendarian hydraulic with 280 degree off-seat duration (232 degrees at 0.050), 0.480 inch lift, and a 109 degree lobe centerline. Rhoads lifters effectively reduce the valve duration at low RPM, and a Cloyes double roller timing chain coordinates everything. I believe, however, that this combination could use more valve lift, and I'll be using a higher lift roller cam and/or higher ratio rockers for my next engine.
On top is a F.I.R.S.T. (Fuel Injection Research System Technology) TPI system, which sports a huge throttle body and runners. This replaced the TBI (Throttle Body Injection) system originally shipped with the car. It is rated to flow enough fuel/air for 450 HP. Sadly, I think the manufacturer (IMPCO aka AirSensors, a California-based firm) has gone out of business. I wonder where I'll get my next mass-airflow sensor... Anyone need a ported TBI intake with all the goodies?
The TPI has its own computer, nestled in the glovebox, which provides buttons to select parameters and a knob to adjust them. Tweaking this thing turns out to be a fun way to pass the time at stoplights, with the runs between serving as tests.
The existing GM ECM (Electronic Control Module, or "computer" by another name) still manages spark timing. I reverse-engineered the ECM tables from the ROM (Intel 2532 EPROM compatible pinout) and did a lot of seat of the pants testing to determine the optimum curves for avoiding detonation and making Mustang drivers feel bad.
Blackjack AK5000 headers wrapped with Thermotech insulation carry the hot gasses out into a dual 2 1/2" exhaust (2 cats). The insulation saves a lot of wear and tear on engine compartment goodies, not to mention the hood paint.
The engine idles well (although a bit rough below 900 RPM) and pulls strongly from 1500 to 5500 RPM. It really kicks you in the pants at 3000 (it smokes the tires in 1st AND 2nd gear)! This mandates a conservative approach to driving in the rain or in any traction-limited situation (a la always)!
I used to work for Summit Racing in the Engine Development department, so if anyone has any Fuel Injection Technical Questions or general Engine Technical questions I would be willing to answer them.
74 Corvette Coupe Specs.
Transmission, Drive Train, and Suspension (getting the go to the ground)
If you remember, the 1982 model only shipped with a 700R4 4-speed overdrive automatic. 1982 was early in that transmission's design lifetime, and (you other 1982 owners probably guessed this already) it ground itself into little metal particles at about 60,000 miles, still coupled to the original unmodified 350 engine. What to do?
I bought a Doug Nash 5 speed, way back before Richmond Gear bought them out and began making a 6 speed (sigh). I also got a Centerforce dual friction clutch setup and a bizillion '80/'81 Corvette manual transmission parts from GM. Everything from the backup light switch to the Z-bar stud on the engine to the clutch/brake pedal linkage had to be dealt with. The GM dealership parts guy began giving me wholesale prices because I was such a regular customer.
I got a shortened drive shaft and special U-joints (one is even Chrysler sized, for Chrysler's sake). The cross-member didn't fit, so I got a late '70s part from a junkyard and modified the transmission mount. Since this cross-member has holes for exhaust pipes on each side (rather than a hump on one side) I had to spring for a custom-bent exhaust system (anybody ever notice that the word "custom" is gold-plated?). The list just goes on and on of big and little things that had to be done. What an exercise, BUT IT WAS WORTH IT!!! The Hurst is pure pleasure to shift, the exhaust note is healthy, the tire smoke impresses the guy behind, etc. This is the way GM should have built the car in the first place. Come to think of it, late model 'Vettes have a lot of these attributes...
Now I had this problem. I kept breaking my differential. The first time, I literally broke the housing into 3 distinct pieces. Let me tell you, it was an expensive sound. I searched far and wide (at the time not having Internet access) and found a little shop in Delray Beach, FL, near my home called (I think) Florida Corvette Calipers or Florida Precision Calipers (at least I know how to drive there). They built me a replacement with a new housing and hardened gears, but in about 6 months I broke off a couple of teeth (another expensive sound). Finally, the owner, Carl, who knows metallurgy, sent off for "special FAA machine shop" gears that I haven't been able to break yet. I'm now using synthetic gear lube, too.
Vette Products keeps my car from dragging on the road and from running into stopped semis and guard rails. I love sending money to these guys:
VP made me a 400 lb fiberglass rear spring to replace my Gymkhana steel spring (to my chiropractor's chagrin). I installed a VP 3/4" rear anti-sway bar and polyurethane bushings for the trailing arms, the spring end links, sway-bar links, the camber arms (struts?), and all of the other squishy parts. I originally put Koni shocks (adjusted to max stiffness) all around, but a broken half-shaft U-joint mandated replacement rear shocks, so I'm now riding on Carrera rears. Its a bit squeaky (due to the poly bushings), but boy does it corner. I can enter a corner 15 or 20 MPH too fast and just go around it! I've left a lot of late model cars in the dust at on-ramps and the like, which usually results in some puzzled expressions (and an inner feeling of joy) should they ever catch up to me.
One thing I'm thinking about doing now is replacing my 550 lb front coils, A-arms, etc. with a VP transverse fiberglass monospring system. This should reduce the unsprung weight a good bit and improve handling over not-so-smooth surfaces, not to mention refresh my bushings. Also, VP updated their rear setup to provide a dual mount for the '82 aluminum cross-truss. I might have to check that one out as well.
I have VP brake calipers in the front and the original (believe it or not) GM calipers in the rear. I'm running carbon-metallic pads all around and all of calipers are plumbed with steel braided brake line. I'm using the VP heavier-than-stock rotors mated with lighter-than-stock hubs. Silicone brake fluid keeps the corrosion down and the boil temperature up. The car stops true and really SHORT. This setup has saved my buns from a crash on several occasions. The only thing I worry about now is being hit by the car behind, but there usually isn't anybody close behind...
For those of you considering carbon-metallic pads, one warning: The friction characteristics change slightly as they get hotter (they grab more when hot). This isn't a problem when you learn to expect it, but please don't let it surprise you when you first put them in. Also, contrary to popular lore, they make a LOT of black brake dust (but don't seem to wear very fast - interesting).
BF Goodrich Comp TA 255-60-HR4s ($85 apiece installed!) are carrying me through the corners, although I can go a lot faster than the 129MPH H speed rating (alas, but where?). These are the best 15" street tires I have ever had, and I sure like the price as compared to those for 16" and 17" rims!
From: Ross Jones <rossjones@ti.com>
Her name is Shamu, and she is a 1973, 454 (engine was balanced and blueprinted, no other mod's), automatic, T-tops, with a major paint job consisting of 4 shades of blue, pearlized white, and black, with some gold pin-stripping.
The interior has been changed to black leather and black carpeting.
The wheels and tires have been altered to larger sizes and much of the engine has been chromed. The front has been changed, nose clip is different, and the back bumper is painted black.
A little history: the previous owner had most of this work done and showed the car (which accounts for the low miles when I got it last year of ~43,000). The car is originally from the Dallas area (Garland) and has always been here. That owner died and his father got the car, but did not want to drive it. He stored it until a machanic I know got ahold of it and fixed it up, as it had not be properly stored.
About that time I was in the market for my first Corvette and went to talk with Jim, the machanic, about Vettes since I knew he fixes/restores them as a side line to his normal auto shop business. After talking to me about what I was looking for, I wanted a 70's, a/c, good condition, he pointed this one out to me. It is really different, and I'm sure many purist would be scratching their heads. But I liked it, and the price was okay. By the way, all the numbers match.
I know it's a bit different, but its a Corvette, and my first!! I love it. I love driving it!! I love to show it (to anyone). I've never had a car I love as much; even my first: a 57 Chevy.
My wife, named her because of the paint job, and it has stuck.
Best regards,