Mike Reynolds's 1974 Spitfire - Chevy V6 Conversion
as published in BritishV8 Magazine, Volume XVII Issue 1, July 2009Owner: Mike Reynolds
BritishV8 UserID: v6spitfire
City: Beaumont, Alberta
Model: 1974 Triumph Spitfire
Engine: 4.8L Chevrolet V6
Conversion performed by: Owner
| Engine: | 4.3L Chevrolet V6, bored and stroked to 4.8L (4.165 inch bore x 3.65-inch stroke,
utilizing a Chevrolet "Bow Tie" engine block and a BRC Performance billet crankshaft.) Normally,
Chevy 4.3L V6's are "even fire" engines. However, the billet crank has common-pin
(non-offset) rod journals like a V8 or an "odd fire" V6, so an odd-fire (MSD
racing-spec) distributor and camshaft were needed too. For the camshaft, a Comp Cams
solid roller cam was selected (255/262 at 0.050", 0.625" lift). The crankshaft pushes
Childs&Alberts (6") Rods with Federal Mogul pistons. The cylinder heads are
from Chevrolet's Bow Tie catalog too. They're aluminum, with raised (23 degree) ports,
2.10" intake valves and 1.62" exhaust valves. The static compression ratio is 11.2:1.
A 2-piece Chevrolet Bow Tie box-style cross ram intake manifold is mated to an
AED 650cfm carburetor. (The design is based on Holley's "4150".)
Note: some of the pictures below show an earlier set-up which included an Edelbrock Performer intake manifold with a 750cfm Carter carburetor. It worked okay, but only got the car into low 12-second quarter mile times. An Edelbrock Performer RPM nitrous injection system was set up for a 100hp shot, but it was rarely used. For NHRA bracket racing, the car is only allowed to run 11-second ET's, and with a 100hp nitrous shot the car would have run sub 11-second quarter miles (and thus would have been disqualified.) |
| Cooling: | custom 19.5" tall by 20.5" wide 2-row aluminum radiator on custom mounts. (The radiator was built by Guyons of Calgary, Alberta, but they're no longer in business.) Flex-A-Lite #150 cooling fan (2800cfm at 2200rpm). |
| Exhaust: | 1.75" headers, into 2.5" pipes through a single Flowmaster 42582 (4" X 9.75") muffler. |
| Transmission: | GM 200-4R automatic transmission with overdrive, connected through
a TCS 2800 stall convertor and through a 3" aluminum driveshaft. (The
transmission was purpose-built using TCI and TCS pieces, and should be
fine to over 600hp. The valve body is still automatic in OD and D, but
it's manual in all other gears.) |
| Rear End: | narrowed Dodge 8.75" axle, with 3.91:1 gears and Auburn Pro-Series limited slip
differential. |
| Chassis: | complete custom chassis, built to comply with NHRA and IHRA requirements. The main roll hoop was bent to shape, then chromed, and then welded to the chassis. |
| Front Suspension: | Chris Alston (Ford Pinto) twin A-arm suspension (24" frame rail width). QA1 single adjustable shocks. |
| Rear Suspension: | custom Bears Performance Products adjustable 4-link suspension with wishbone locator. QA1 single adjustable shocks. |
| Brakes: | 1991 Ford Taurus master cylinder (non ABS, Raybestos 390049). Adjustable proportioning valve. (front) Wilwood 1989 Camaro spec disc brakes with bearing conversion kit for Mustang II spindles. 11" rotor. (rear) Wilwood "Pro Street" disc brakes. 12" rotor. |
| Wheels/Tires: | (street) 16x8.5 ASA, with 205/45 front and 245/45 rear Avon tires. (strip) 15X8 Bogart rims with Mickey Thompson 24"x9" slicks (rear). |
| Body: | all badges removed. Wheel wheels opened 2". New dashboard and transmission tunnel. |
| Electrical: | a mix of VDO and Stewart Warner gauges. Panasonic head unit. Elemental Design
speakers. Audisson amplifier. Optima Red Top battery. 80Amp Nippendenso alternator
(from a Toyota 4-Runner). |
| Weight: | 2312lbs with me in it. 48% front / 52% rear. |
| Performance: | runs mid 11-second quarter miles (without NOS). Handles like a go-cart and
stops on a dime. I've hit 145mph, with more left to go. Because of the 4-link
and the adjustable shocks, when I go to the track and bolt on a set of slicks,
it hooks up hard (with 1.43 second 60-foot times). It will pull the front
wheels ever so much (6" to a foot off the ground) and then just haul butt. |
| Miles Driven: | about 2300 kilometers, as of March 2009. |
| Comments: | the car is better then I expected. Due to its size and weight, combined with
the suspension, it handles very well. It accelerates like a train, and at idle
it sounds like it has a healthy small block rather then a V6 due to the single
muffler combo. Building it was a much bigger project then you might think,
because I wanted it built to show-winning appearance and still be able to
drive the bag off of it! |
Building the Chassis:
Chris Alston (Ford Pinto) twin A-arm front suspension.
Bears Performance Products adjustable 4-link suspension with wishbone locator.
Dodge 8.75" axle. / Flowmaster 42582 (4" x 9.75") muffler.
Wilwood Pro Street disc brakes (for Dodge axle), with 12" rotors.
15x8 Bogart rims with Mickey Thompson 24"x9" slicks (rear only).
Complete custom chassis, built to comply with NHRA and IHRA requirements.
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Putting the Pieces Together:
1974 Triumph Spitfire body, stripped and in the process of being reconditioned.
Now the Spitfire body is installed on the custom chassis.
GM 200-4R automatic transmission with overdrive.
Piece by piece, the car is being put together now.
Okay, we're ready for those QA1 single adjustable coilover shock absorbers now!
In this photo the roll hoop is being precision fitted. (Notice the convertible-top frame...)
At this stage the brake and cooling systems are being installed...
...and the fuel system too. (The nitrous bottle ultimately won't get much use.)
The front clip goes on... luckily there's a big scoop to clear the air filter!
Parts go on... they come off... they go back in... (this time with carpet under them!)
The Completed Conversion:
This Spitfire runs mid 11-second quarter miles (without NOS)!
