Curtis Jacobson's 1971 MGB/GT with Buick 215 V8
(originally published in MG-V-8 Newsletter, Volume 5 Issue 1. Revised...)
Owner: Curtis Jacobson
City: Greensboro NC (later moved to Colorado)
Model: 1971 MGB/GT (purchased for $1.00 in 1987)
Date of Conversion: 1991 - 1993
| Engine: | a 1963 Buick Special was purchased complete and running for $150. (No kidding!)
Its four-barrel 215cid engine was rebuilt with 0.030" oversize pistons, a
Kenne-Bell cam ("1XA" .462" lift, 260 degree duration, 110 degree lobe center),
Edelbrock carburetor, Mallory Unilite distributor, and stock starter. Home-made engine mounting brackets (using Volvo Truck radiator mounts.) Heater removed and air inlet converted for cowl induction, with a panel-type filter at the firewall. A Facet fuel pump was installed, but it was loud from day one and it didn't live very long, so it was replaced with a much better Mallory "Series 70" pump. |
 This shows one of the custom motor mounts and the Buick V6 "metric" oil pump, which angles the filter forward. Note: my friend Pete at Mantell Motorsport media blasted & powder-coated all the black steel parts shown here.  Notice the tiny Nippondenso alternator and the external clutch slave cylinder, both on custom brackets. |
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| Cooling: | stock MGB radiator, except re-ported and with filler neck removed. I drilled out the spot welds and replaced the old mounting flanges with new home-made ones. Plastic remote surge/fill tank (VW Jetta) fitted high on the firewall. New structure and ductwork around the radiator for improved chassis strength and air flow. Twin 8 1/4" electric fans (Honda Civic) ahead of the radiator, with low-clearance fan rings to increase fan efficiency. Stainless steel bug screen on a lightweight aluminum frame. |
 "Tri-Y" headers on a V8 engine improve exhaust scavenging by separating pulses as much as feasible. For the Buick V8's firing sequence, cylinders 1 & 5 need to be paired. Also, 3 & 7, 2 & 4, and 6 & 8.  The home-made sand-bent Tri-Y headers have slip joints at the collectors for easy installation. |
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| Exhaust: | home-made sand bent Try-Y's into dual mufflers pocketed under the seats,
with exhaust dumping onto the ground just ahead of the battery boxes. Making our own headers was really fun and rewarding, but the reason we made them was that back then we didn't know any good option. The RV8 hadn't been introduced yet. I'd heard a rumor that mail-order "block hugger" headers were restrictive and prone to cracking at the welds, plus they were expensive. If we made headers again they'd probably look more like RV8 headers, but they'd be sand-bent.) |
 A Buick V6 "metric" oil pump facilitated doing away with the previous remote oil filter. |
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| Lubrication: | I originally used the Buick 215 V8 front-cover and oil pump, an aftermarket "high-volume" kit (longer gears and aluminum spacer) and remote filter... but the original valve body was scored and would occasionally lose prime. Also, I came to the conclusion that high-volume kits are a scam, and remote filters are messy. I simply replaced the front cover and oil pump with new V6 parts from the local Buick parts counter. The Buick V6 "metric" oil pump has an angled filter mount. With the engine mounted where I've got it, a remote filter was no longer necessary because the V6 filter spins right on! I have oil pressure as soon as the starter spins, and great oil pressure under all conditions. |
| Transmission: | 1992 Borg Warner T-5 5-speed manual, purchased new from Rockland Standard Gear for approximately $1000. Transmission is the same as a 1992 Camaro's, with the GM (angled) mounting and a 1 1/8" 26-spline input shaft, friction-lined rings (instead of brass synchros) and integral linkage. |
| Bellhousing: | Buick, purchased loose with T-10 transmission, flywheel, pressure plate, etc. (I turned around and sold the T-10, and recouped my expense.) |
| Flywheel/Clutch: | I started with stock Buick parts. After running the car for several years I removed the flywheel and had a machinist friend grind off that heavy outer rim. The lightened (before: 33.2lb, after: 27.4lb) flywheel proved much more appropriate! However, after about fifteen years, when the original rope-type rear main oil seal failed and oiled down my clutch I decided to try something different. As long as I was replacing my original clutch (which had been from a 1992 Mercedes 190SL) I decided to "upgrade" to a new 10.4" Camaro clutch and diaphragm pressure plate. I don't need these heavier-duty (and just plain heavy) parts yet, but I might if I ever get around to installing a more powerful (Rover) engine. |
 Custom mount for a Girling slave cylinder, and shortened throw-out fork. |
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| Clutch linkage: | originally, I fitted a Girling (0.87" bore) slave cylinder to the side of the engine, pushing a shortened lever. It worked, but pedal effort was too high with the original three-finger pressure plate. After running the car several years I fitted a Tilton "hydraulic throw-out bearing". The HTOB helped with pedal effort, but frankly the Tilton unit was a pain to set up and bleed. (It's extended length wasn't as long as I think it should have been, so it was operating at its limit. Also, I had a seal failure shortly after initial installation.) When I switched to a diaphragm pressure plate I decided to go back to a simple, serviceable external slave cylinder. |
 The home-made Panhard rod attaches to a Ford 8.8 axle. A "doubling plate" sandwiches and reinforces the trunk floor. |
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| Suspension: | I installed a Moss coil-over front suspension (which is no longer available).
It hasn't given me any problems, but the design was rather "unambitious".
For example, castor and camber angles are stock and non-adjustable. Kingpins, leaf springs, etc. were all replaced with new parts. An Adco front anti-sway bar was installed on polyurethane mounts. I made my own steering column to move the whole driving position rearward in the car, not just because I'm tall, but also for weight distribution. On the rear I installed telescoping shocks... but I found the ride to be very harsh, so I discarded the shocks that came with the kit and replaced them with more appropriate shocks ('84-'88 Dodge Colt, Monroe 5877ST). They're still not great, but they're a whole lot better. I can't stress enough how much adding a Panhard rod improved my car. I'd driven the conversion several years before I fabricated one, but it certainly makes the car feel more confident in corners. |
| Rear End: | 1992 Ford Mustang 5.0 8.8" Traction-Lok limited-slip differential with 3.27:1 gearing (purchased at a salvage yard for $500). I had the housing narrowed and leaf springs brackets installed locally for $100. Custom Moser alloy axle shafts cost an additional $290. The hardest part of fitting the Ford axle was fabricating a parking brake cable system. |
| Brakes: | new MGB master cylinder. (Note: these are now made by Lucas instead of Lockheed). front - MGB (Brembo) rotors, EBC "Yellow Stuff" pads, Wilwood 2psi residual pressure valve. rear - Ford 9" diameter drums, 13/16" wheel cylinders, Wilwood 10psi residual pressure valve. Lokar parking brake cable set connected to (3/4") extended MGB lever. |
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| Wheels/Tires: | Falken Azenis RT-615 tires (205/50, 20.4# new) on Panasport 8-spoke wheels
(15"x6", -22mm offset, 15.0# each, polished rim). McGard 64000 lug nuts (1/2"x20 by 1.5", cone seat). Note: I formerly used Goodyear 195/60 tires on Minator 8-spoke (14"x5.5", 13.6#) wheels, and they're shown in the photos here. |
 The original plan was: "If it doesn't look like a racecar part, take it out." I had 2nd thoughts, and added a speedo.  2500rpm at 70mph... |
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| Instruments: | Fuel level - Stewart Warner (electrical) Oil pressure - Stewart Warner (mechanical) Water temp - Stewart Warner (electrical) Speedometer - VDO (electronic/programmable) Tachometer - Sun (I got it free. It doesn't match, but it works well) Notes: the first three gauges (above) are mounted in a removable panel with the switches, circuit protection, etc. In theory, you could unfasten four Dzus (quarter-turn) fasteners and a couple electrical connectors and take the whole assembly to your workbench for service, but if I ever rebuild it I'll move the circuit protection to the area over the passenger-side footbox to simplify the overall design. |
| Electrical: | Nippondenso integral-regulator alternator from a Chevy Swift (Suzuki engine).
This alternator is very lightweight and perfectly reliable. Also, it was free. All new home-made wiring featuring crosslink insulation (instead of PVC) and Packard Metri-Pac sealed connectors. Where possible, the wiring has been moved inside the car (instead of running under the floorboards, etc.) Fuses have been moved inside the car. (What were they thinking!) Single 12-Volt battery in passenger-side location. A battery disconnect switch (with key) has been fitted very near the battery. I've upgraded most of the lights to more modern designs: front turn signals from VW Jetta, side markers from Hyundai Excel, license plate lamps from Toyota Corolla, and a Chevy S10 rearview mirror with integral map lights in lieu of the original dome lamp. All these lights function better than original equipment (e.g. better reflectors and fresnel lenses, lighter-weight, more streamlined styling, plus they're inexpensive and pretty much maintenance-free! In my experience, stock MGB exterior lights are prone to condensation and subsequent corrosion.) |
| Paint: | PPG basecoat/clearcoat. The color is one of the darker shades of British Racing Green - Jaguar's "Brooklands Green" (from the mid-nineties) - with a White Sebring Stripe. The car's interior has been painted to match. Floorboards, luggage area, tranny tunnel, etc. were painted with rugged, textured rocker-panel paint. Note: I recently sent a big batch of steel engine compartment parts off to Pete Mantell of Mantell Motorsport to media blast and powder coat in satin black epoxy. I'm very pleased with the look, and Pete is always a WONDERFUL, WONDERFUL person to work with! Of course, the powder-coated finish should prove more durable than the previous paint job. |
 The six-point roll cage was made from 1.75" seamless (DOM) mild steel tubing, w/ 0.090" wall thickness. Note the horizontal tubes (a) under the dashboard, (b) at shoulder-strap height, and (c) low, behind the seats. In this view, you can also see the built-in tool chest. Its lid is held down by Dzus quarter-turn fasteners. 
The lightweight polycarbonate rear quarter windows are easily removable for terrific ventilation.They're secured in place with Dzus quarter-turn fasteners, three per window. (The righthand photo also shows one of many supplemental cage-to-body brackets.) |
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| Misc.: | six point roll cage (which aids handling due to improved chassis rigidity), plus
I stitch/seam-welded all body seams in the engine compartment for added strength.
Five point seat belts. Home-made aluminum dashboard (with early-model MGB
padded eyebrow) and aluminum door trim. I invented quickly-removable rear quarter windows. The glazing is polycarbonate instead of glass for a big weight savings, and they're mounted to lightweight steel box-tube frames which are held in by three quarter-turn (Dzus) fasteners per window. Built-in tool box in cargo area. |
| Cost: | right about 10 grand. I didn't save receipts, and I try not to think about it. Honestly, these cars can be pretty economical if you're disciplined. I did most of the work myself or with the help of friends, including especially Rob Henson (formerly of Virginia Tech and Volvo Trucks, now at John Deere) and Ashley Dudding (formerly of Virginia Tech and Volvo Trucks, now at Hendrickson), two really gifted engineers. Ashley is a master of the almost-lost art of welding with acetylene. |
| Opinions: | I have a very strong preference for chrome-bumper MGBs, and especially GT's, so
I generally disagree with the common advice to seek later model cars for conversion.
The later chassis may possibly make sense for people who will be buying pre-made "kit"
parts and who are intimidated by a little metal work, but otherwise it offers little
advantage. To handle or look right, later MGB's should be lowered to early-model specs
or even lower. They also need to lose their awful, heavy black bumpers. Those changes
have offsetting costs of their own. Contrary to common advice, I didn't have any
problem locating my Buick 215 V8 engine with plenty of clearance to the steering/suspension
crossmember and unmodified steering rack. (I've never understand the make-work
suggestion of using a later model "rubber-bumper" crossmember, rack, steering u-joint,
steering column, etc. - plus lowered springs. That's nuts! My oil filter even spins
directly onto the engine. How often do you see that in by-the-book conversions? It's
proof that there are many ways to skin a cat.) Finally, at the time and place where
I built my car the state emissions requirements would've been harder to meet with a
later-model car. I would've had to fit catalytic converters for annual inspections. On my cars, if a part breaks I usually refuse to replace it with a similar part. I require a replacement part that is better by design or of demonstrably better quality. In some cases that pushes me into unorthodox designs, but frankly I think this philosophy has helped me to build a much more reliable MGB. The main reason British cars have a lousy reputation for reliability is their electrical systems. If it weren't for Lucas, everything would be different - there might still be an MG dealer in your town! If you're willing to accept the challenge of upgrading to a better engine, you certainly shouldn't be intimidated about upgrading the car's electrical system. Research first, starting with the BritishV8 newsletter, of course! You really can re-wire your car with better parts and techniques than MG ever had access to. I particularly recommend Japanese OEM alternators and electric fans. Wherever possible I try to use modern-OEM parts, and I usually prefer parts from a junkyard or local car dealer's parts counter over anything from a discount parts superstore or hot-rod parts catalog. (I refuse to buy parts from Walmart, or any part made in mainland China.) There are parts on my MG from at least twelve different OEM's representing six countries. I've hardly bought anything from the folks who specialize in parts for MGB engine conversions, so I have few opinions on their stuff. |
| Future: | This little car still makes me smile every single time I drive it. I've had her
over twenty years and I'm comfortable with her, but she is by nature and intent a continuing
project. Since sorting out the conversion she's proven very reliable, although after about
fifteen years I did have to replace a leaky rear main bearing seal, which required pulling
the engine. Some ideas for future modifications include: an updated rear suspension
(probably a 3-link or 4-link design, to save weight and because I'm tired of my sagging
leaf springs.) I'd like to fit rear disc brakes (possibly from a mid-nineties Honda or
Nissan), dual master cylinders with an adjustable bias bar, bead-rolled aluminum interior
trim panels, and especially importantly electronic fuel injection.
Frankly, I've driven much more powerful and refined MGB V8 conversions... but to me Bonnie
still feels, sounds and looks more like a racecar than any other MGB I've driven. I wouldn't
trade her! (Being a GT, plus having a cage, my car is really noticeably more rigid and in
my opinion that's a great thing.) My main plan for the future is just to drive more! |
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I prefer a mechanical throttle linkage, instead of a throttle cable.
In the bottom right you also see plumbing for the brakes and clutch slave cylinder.
Home-made cowl / cold-air induction! A rectangular panel air filter is mounted into an aperture in the firewall.
A VW Jetta pressurized surge/fill tank is mounted on the passenger-side firewall, and plumbed with hard lines.
This photo shows muffler placement, muffler heat shields, and Lokar parking brake cables.
As measured at British V8 2008, this car weighes 2180 pounds "wet" (i.e. full tank of fuel).
That's about 130 pounds lighter than original, and 247 pounds less than a "factory" MGB GT V8.
Corner weights: 538 (LF), 529 (RF), 566 (LR), 547 (RR). Distribution: 48.94% (front) to 51.06% (rear).
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