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Mike Domanowski's MGB Olds V8 Nitrous Build

Mike Domanowski (car owned by wife Amy Sue Domanowski) · MGB

MG MGB

BritishV8: the site for enthusiasts of modified British sports carsOriginally featured in Volume XI Issue 3, September 2003, written by Kurt Schley

Read the full write-up at BritishV8: the site for enthusiasts of modified British sports cars ↗

Photo: BritishV8: the site for enthusiasts of modified British sports cars

An MGB fitted with an Oldsmobile 215 V8 and nitrous, stepping up to a 269ci stroker

Mike Domanowski built a nitrous-fed Oldsmobile 215 V8 swap into his wife Amy Sue's MGB, then commissioned D&D Fabrications to build a 269cid stroker motor to take over nitrous duty with much more headroom. The write-up is of interest for its detailed stroker engine spec sheet and its account of sourcing a rare Jetfire block and marine-spec cylinder heads for serious power.

Specs

As stated in the original write-up.

Engine
Oldsmobile 215 V8, upgrading to a 269cid stroker on an Olds Jetfire block
Displacement
269cid
Bore
3.530"
Stroke
3.4" (Buick 300 crankshaft)
Block
Olds Jetfire
Heads
Olds -829, ported, 10.3:1 compression
Piston
TRW2492-F
Deck Height
0.000"
Chamber Volume
41cc
Compression Height
1.580"
Compression ratio
10.3:1
Intake valve
1.625"
Exhaust Valve
1.425"
Valve Spring
D&D 813
Lifter
D&D 896
Camshaft
Crower 50232
Head gasket
0.040" composite
Con Rod
Eagle EAGCRS570053D (5.70" length)
Rings
Hastings 2M5650 +.030"
Rocker Arms
Stock Olds 215
Flywheel
D&D 467025
Pressure Plate
D&D 360700
Clutch Disc
D&D 26027
Gearbox
T5 World Class 5-speed transmission from D&D Fabrications

Parts used

Parts named as used in the original write-up, grouped the way the Parts page groups them. Where one of the shops we index lists the same thing for this car, it is shown underneath with a link to the shop.

Engine 13

Fuel & Ignition 3

  • MSD billet distributorMSD

    Ignition distributor fitted for spark control

  • MSD 6AL control boxMSD

    Ignition control box paired with the billet distributor

  • NOS Sportsman Fogger nitrous systemNOS, installed by Jeff at Action Cycle

    Direct port nitrous injection system installed into each intake runner, capable of a 300HP shot, currently run at 80HP

Cooling 1

  • Griffin aluminum radiator (custom)Griffin, designed with M&G Vintage

    Custom cooling radiator designed for the car

    In the shops
    Aluminum Radiator ↗Moss Motors – Triumph TR6/TR250· $355.00 USD
    Aluminum Radiator ↗Moss Motors – Triumph TR6/TR250· $358.50 USD
    Aluminum Radiator ↗Moss Motors – Triumph TR6/TR250· $364.00 USD

Gearbox & Drivetrain 5

  • D&D 467025 flywheelD&D Fabrications

    Flywheel for the stroker engine/clutch assembly

  • D&D 360700 pressure plateD&D Fabrications

    Clutch pressure plate for the new drivetrain

  • D&D 26027 clutch discD&D Fabrications

    Clutch disc paired with the new flywheel and pressure plate

    In the shops
    Clutch Disc - MGB ↗bpnorthwest.com· $59.95 USD
    Clutch Disc (Girling) ↗Moss Motors – Triumph TR6/TR250· $64.99 USD
    Heavy Duty Clutch Disc (MGB) ↗bpnorthwest.com· $105.39 USD
  • T5 World Class 5-speed transmissionD&D Fabrications

    New gearbox to be installed alongside the stroker engine

  • Ford/Currie 9 inch rear endCurrie

    Rear axle fitted with a 3.00:1 final drive ratio

Brakes 2

Photos

13 pictures collected from the write-up, in the order they were posted, shown from BritishV8: the site for enthusiasts of modified British sports cars. A picture opens larger here, with the way through to the page it is on.

Michael's MGB with Oldsmobile 215cid V8 and NitrousPhoto: BritishV8: the site for enthusiasts of modified British sports cars
Amy Sue Domanowski's MGBPhoto: BritishV8: the site for enthusiasts of modified British sports cars
who made that master cylinder?Photo: BritishV8: the site for enthusiasts of modified British sports cars
Nitrous oxide portsPhoto: BritishV8: the site for enthusiasts of modified British sports cars
NOX solenoid valvesPhoto: BritishV8: the site for enthusiasts of modified British sports cars
NOX manifoldPhoto: BritishV8: the site for enthusiasts of modified British sports cars
double roller timing chainPhoto: BritishV8: the site for enthusiasts of modified British sports cars
stud mounted cylinder headPhoto: BritishV8: the site for enthusiasts of modified British sports cars
Olds 215 inlet portsPhoto: BritishV8: the site for enthusiasts of modified British sports cars
Olds 215 exhaust portPhoto: BritishV8: the site for enthusiasts of modified British sports cars
Buick 300 crankPhoto: BritishV8: the site for enthusiasts of modified British sports cars
MGB hood scoopPhoto: BritishV8: the site for enthusiasts of modified British sports cars
Donate Now!Photo: BritishV8: the site for enthusiasts of modified British sports cars

How it was done

Starting point: a nitrous-fed Olds 215

Mike Domanowski's wife Amy Sue owns an MGB fitted with a stock-displacement Oldsmobile 215 V8. The car already runs a nitrous oxide system, though Mike has kept it conservative, using only an 80 HP shot on the current motor even though the system is rated for far more.

Why a stroker motor

Because the Olds 215 is known to be limited by its heads rather than bottom end, Mike turned to Dan LaGrou at D&D Fabrications to build a 269cid stroker to replace the stock motor, with the nitrous system set to be transplanted across once the new engine is installed.

A rare block for insurance

The stroker was built on a rare 1962-63 Oldsmobile Jetfire turbocharged block, chosen for its beefier main bearing caps and factory-upgrade 12-point cap bolts, giving extra strength to handle nitrous cylinder pressures.

Head studs and big-port heads

APR head studs replaced the standard bolts to cope with the added cylinder pressure under nitrous. The engine uses Olds -829 heads at 10.3:1 compression that were originally ported and reworked for a marine racing application that never reached the water, giving unusually large intake and exhaust ports to feed the bigger motor.

Supporting upgrades around the car

Beyond the engine, the MGB received a Ford/Currie 9 inch rear end with 3.00:1 gearing and Ford Explorer rear disc brakes, a Master Power dual master cylinder and booster brake system, a Griffin aluminum radiator designed with M&G Vintage, and MSD billet distributor ignition.

The nitrous installation

The NOS Sportsman Fogger nitrous system was installed and fabricated by Jeff at Action Cycle, who also built the nitrous setup on Mike's Kawasaki KZ1300 motorcycle. It feeds nitrous directly into each intake runner and is rated up to a 300 HP shot.

Goals for the new build

With the stroker motor and a D&D-sourced T5 World Class 5-speed gearbox going in, Mike and Amy Sue were aiming for over 500 horsepower at the rear wheels, with the article noting a follow-up report was expected once the car had some miles on the new combination.

A summary in our own words. The full account, with all its detail, is in the original write-up: read it at BritishV8: the site for enthusiasts of modified British sports cars ↗

Worth knowing

  • A rare factory-upgraded block, like the Jetfire, can add real strength insurance when running nitrous.
  • Head porting is often the limiting factor on small-displacement V8s like the Olds 215, so invest there for real gains.
  • Upgrading head fasteners to studs is worthwhile before pushing cylinder pressures higher with nitrous.
  • Keeping nitrous shots conservative on a stock engine is a sensible step before a stronger bottom end is in place.
  • Sourcing specialist engine and drivetrain parts from one experienced builder can simplify a complex V8 swap.

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