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Affordable Corvette Supercar: Beyond the Crate II

Affordable Corvette Supercar: Beyond the Crate II


A 1995 C4 Corvette is one of the sexiest and most affordable supercars you can buy. They are available from 5-7K and they are already equipped with a fuel injected LT1 engine and a very competitive handling package. With the possible exception of a wheel and tire upgrade you won't have to touch the suspension system to enjoy all the built-in performance of the Corvette's high performance suspension. And the 300 horsepower engine is a strong reliable performer that offers plenty of potential for power upgrades or a complete rebuild like the 383 stroker we built for our in-house project car. You can see the detailed buildup of this engine package in Part 1 here: 383, Beyond the Crate.
Tom Coon (left) and Alex Ramirez of Bone's Fabrication muscled the renewed LT1 back into the car and made sure all the proper connections were secured.
On the Mustang chassis dyno at Ray McClelland's Full Throttle Kustomz hot rod and dyno shop in Fillmore, California.

We'll detail some of the secondary modifications below, but first the results of the dyno test and tuning session where the factory computer was re-tuned to accommodate the larger displacement, hotter camshaft and other performance mods that we added to the Summit based stroker engine. One of the first things that impressed us was the fact that the newly modified engine started right up on the factory ECM and ran beautifully with no check engine light. We assumed that 33 extra cubic inches combined with the GM "Hot" cam, 1.6:1 roller rockers, Edelbrock intake manifold, bigger injectors and Holley throttle body would set off alarms. Didn't happen and the car drove well. Any throttle at all off idle easily lights the tires.

The purpose of the chassis dyno test was to fine tune the factory PCM to the new stroker engine package. To accomplish this we enlisted the aid of former Chevrolet Performance engineer Mark McPhail to come out and put the tune on it at Ray McClelland's Full Throttle Kustoms shop in Fillmore, California. Ray has a fantastic shop and a Mustang chassis dyno where he tunes customer's performance cars everyday. We put the two of them together to see if they could put the max demon tweak on it for that last little bit of power and optimum drivability.

Some calibration issues were ironed out and the combination found its sweet spot, delivering a very broad flat torque curve with over 400 lb-ft of torque at the rear tires. That's over a hundered more foot pounds than the car delivered with the stock engine. The cam is very streetable and the car is now a tire shredding monster the minute you even touch the gas.
So we nudged out a hair over 400 horsepower at the tire with a 2% correction factor. Depending on drive train losses that puts flywheel power somewhere within the 430 to 450 horsepower range we had predicted. That's quite good for a 218 degree cam which tends to be milder in a larger displacement engine. And 437 lb-ft of torque at the tire is about 140 foot pounds stronger than what the stock engine delivered. That helps a good bit in overcoming the car's 3.36 rear drive ratio. McPhail did a great job of tuning the ECM and matching it with a new Granatelli Mass air meter.

For a little perspective, take a close look at the installed engine. With the exception of the coated Hooker headers, Accel plug wires with ceramic plug boots and Trick Flow oil separator, the engine looks completely stock. All the good stuff we ordered from Summit Racing is inside the engine. Part of the compelling appeal of this Corvette package for building a budget savvy mail-order supercar is that so many of the car's systems are already highly engineered. As described in Part 1, 383, Beyond the Crate. the engine sports a full complement of aftermarket performance parts securely wrapped in the attractive factory engine package. At less than half the cost of any current performance muscle car, it's a sleeper supercar upgrade that almost everyone can afford

The factory cold air inlet package is retained and is perfectly adequate to service the engine's air demand. It completely isolates inlet air from hot underhood air while providing adequate air flow and filter area. Unlike almost every cold air package made for every car and truck it doesn't place the filter in an open box exposed to engine compartment heat. Note also that the filter housing and flow path are made of insulating plastic and composite rubber to resist underhood temperatures.  If you buy a cold air package with a filter in an open underhood box you're pissing in the wind. And it is worse if the filter housing and flow path are made of chromed metal.

Another hidden asset of this alternate supercar build is a performance transmission upgrade in the form of a B&M 4L60E transmission ordered via Summit Racing.  You have to be careful ordering because there were changes in the nineties as they transitioned from 700R4's to the 4L60E. Earlier ones had the one piece trans and bellhousing while later ones were separated at the bellhousing. You will need your exact year and model as they are electronically controlled transmissions and the computers are different after 1995 when they transitioned to OBD II management. The Summit Racing part number for this transmission is BMM-117308, but yours may be different depending on the manufacture date of your vehicle. Either way, B&M outfits these transmissions to provide firm shifts for street/strip duty and they feature a standard shift pattern with:

  • B&M 4L60E automatic, PN BMM-117308
  •  B&M Holeshot converter, PN  BMM-70419 (2400 rpm stall)
  • Recalibrated valve body
  • Beast Sunshell
  • Reinforced input drum
  • All new solenoids and wiring harnesses
  • Performance pump assembly
  • B&M friction plates
  • Forward Pattern Includes:
  • Case 7 Hole Bellhousing
  • Max 550 HP / 450 Ft/Lbs.

Who wouldn't want to drive this classy looking Corvette? Check this baby out with it's new shoes. Hurst Dazzler Gloss Gold Machined Wheels and Mickey Thompson rubber all around are the perfect upgrade to complement the car's powerful new guts. If you want to duplicate this look here are the sizes and manufacturer's part numbers you need.

Front Wheels    Hurst 17 x 9    PN 806045
Rear Wheels    Hurst 17 x 10.5   PN 806047
Front Tires    Mickey Thompson 275/40R-17   PN 6275
Rear Tires    Mickey Thompson 315/35R-17    PN 6278

So what makes this package so attractive? The roughly 20K cost is less than half of most of the current muscle cars on the list below. Factor in financing, interest and insurance and they all cost a bundle. Here you get a very accomplished '90's supercar with a potent engine upgrade that will perform as well as any of the cars on the list. Even better, you get to wrench on it and build it yourself using top quality parts from America's leading mail-order supplier.  Note: MSRP prices are ballpark numbers from dealers.
2016 Camaro
MSRP: From $41,300
Horsepower: 455 hp
6.2 L V8

2015 Chevrolet Camaro ZL1
MSRP $55,505†

Mustang GT
MSRP: From $40,000
Horsepower: 435 hp
Engine: 5.0 L V8

2016 Ford Shelby GT350 Base
MSRP $47,795

2016 Challenger SRT Hellcat RWD
*MSRP Starting At: $62,495

2016 Challenger R/T Scat Pack RWD
*MSRP Starting At: $37,995

2016 Challenger SRT 392 RWD
*MSRP Starting At: $49,195

SOURCES:
Full Throttle Kustomz
220 E Telegraph Rd.
Fillmore, CA 93015
805-200-5500
www.fullthrottlekustomz.com
Hurst Shifters/Wheels
100 Stony Point Rd., Suite 125
Santa Rosa, CA 95401
707.544.4761
www.hurstshifters.com/wheels
McPhail Performance Engineering
1375 Logan Ave., Unit D
Costa Mesa, CA 92626
714-852-3655
www.mcphailperformance.com
MICKEY THOMPSON PERFORMANCE
4600 Prosper Drive
Stow, OH 44224-1038
(330) 928 - 9092
www.mickeythompsontires.com
Summit Racing
Customer Service:
1 (800) 230-3030
Tech Support: 1 (330) 630-3030
www.summitracing.com