STAG V8 ENGINE

HOW TO GET MORE POWER

There is quite a bit we can do to get you more power from your Stag engine but bear in mind that there is a reliability trade-off as the Stag engine is not that robust. If you want better reliability a Rover 3500 conversion with a Rover 5-speed gearbox and a Holley carb on an Offenhauser manifold will give you 155 bhp. Or if you want even more power you can go the whole hog (and why not?) and fit a Rover 3.9, 4.2 or 4.6 fuel injected engine producing over 300 bhp. I can help you with everything you need and shedfulls of advice.


stromberg carbs

Reconditioned exchange Stromberg carburettors for Stag

Original Stromberg carbs
fully reconditioned

Plated and polished with new needles, jets and seals. Assembled and mounted on centre pedestal

monarch tubular exhaust manifolds
FOR ROVER 3500, EFI & STAG ENGINES
Triumph Stag exhaust manifolds
Stag Manifolds
  • MANDREL FORMED BENDS - no reduction in diameter
  • 304 GRADE STAINLESS STEEL - 18% chrome, 8% nickel
  • NO NEED TO MOVE ALTERNATOR
  • STAG ENGINE MANIFOLDS 13/8" DIAMETER TUBE
  • ROVER ENGINE MANIFOLDS 15/8" DIAMETER TUBE
  • LINK PIPES FOR STAG & ROVER ENGINES
  • 10% INCREASE IN POWER - 20% WITH MY HOLLEY CONVERSION
holley 4-barrel carbs - special features offered by Monarch

I can offer you a kit at the lowest price (see below) with extra features as follows:
Holley carburettor for Triumph Stag
Holley Carb
  • All ports not needed closed off for you
  • Supplied correctly jetted for Stag engine
  • Comprehensive fitting and set-up instructions
  • Properly engineered, high quality, fully adjustable throttle cable and bracket assembly (no cutting, crimping or soldering to do) with ball and socket connection to carburettor. This is essential for low wear, reliability and long trouble-free life. Very easy to fit.
  • The only adaptor plate that is angled to compensate for engine tilt which is necessary for improved performance
  • Large flat pancake high-efficiency air filter
triumph stag manifold adaptor plate for holley carb
7o Adaptor Plate

adaptor plate side view
Side view Adaptor Plate
STAG Adaptor Plate available, or for maximum power your inlet manifold can be modified
ROVER Offenhauser 3600 Inlet manifold, superb performance

CLASSIC OPTRONIC SOLID STATE IGNITION KIT
No contact breaker points to adjust ever again - Solid state optical switching
(includes fitting kit Fk113)
Complete Kit£210
CLASSIC OPTRONIC SOLID STATE IGNITION KIT
As above with additional Classic Mounting Bracket MK006
£222
HIGH PERFORMANCE OPTRONIC IGNITION KIT
Suited to sports performance engines such as the Stag, this kit gives you all the benefits of the Optronic system but in addition comes with Lumenition's own "Constant Energy High Performance" low-resistance, high quality sports coil, electronically matched to the Power Module. This coil has only 0.9 Ohms resistance compared to 2.5 Ohms on your standard coil.
The microcircuit control of the coil current gives optimum performance over speed and voltage range ensuring constant maximum spark energy at the coil.
Variable dwell angle, optimising energy use to prevent low-speed coil overheat.
Automatic switch-off, preventing electrical damage in the event of the ignition being left on. (includes fitting kit Fk113 and mounting bracket MK006)
£312
GAS-FLOW INLET & EXHAUST PORTS in your heads. 10-15 bhp more
important Please don't post to me but to the machine shop address you will be given after receipt of your order
Per Head £225
To match ports to inlet manifold
Per Head £75
HIGH-PERFORMANCE EXCHANGE RADIATORS
Triple-flow high-efficiency staggered core for max cooling
£390
Triple-Flow Ultra-High Efficiency Q Core for even greater heat dissipation and absolute maximum cooling
£410
Exchange Surcharge - on both above items£50

2000 SERIES FANS As a primary, 13" 13HD/Tri/B 15A, 300W
£175
As a secondary, retaining standard fan, the 13" 13/Tri/B 12.5A, 150W
£140
OR, as a primary, the 16" 16/Tri/BX 21A, 250W (Just fits)
£165
TUBULAR EXHAUST MANIFOLDS
incl front 900 bends 304 grade st/steel 13/8" dia primaries with smooth mandrel-formed bends (no reduction in diameter)
NB. No need to move alternator. Suitable for Left Hand Drive cars but cannot be fitted to cars with air-conditioning.
Set £460
EXHAUST GASKET SET
£15
Link Pipes - to fit to standard Stag silencers.
Please select the part no. required to match your gearbox:

Manual with A overdrive ('70-'73 to LD 21230) ----------- part TH265
Manual with J overdrive ('73 onward, from LD21231) -- part TH266
Automatic BW Type 35 ('70 - '76 to LD41993) ----------- part TH265
Automatic BW Type 65 ('76 onward from LD41994) --- part TH267

NB. These are OK for LHD but not suitable for aircon
Part No.
£72 /pr
4 BARREL CARB KIT - Everything you need
As featured above.
Gearbox
£565
You MUST specify your gearbox type else kit for Manual will be sent by default.
NB. The Webber 500 4-barrel is TOO BIG for the Stag engine. It was designed for far bigger engines and will only be operating in the bottom 25% of its band. The Holley on the other hand was specially designed for small V8's. Lowest kit price available today
4 BARREL CARB
Uses 2 for normal running & 4 for full power (2nd two vacuum operated). Jetted for Stag. Bolt on and go. 10 BHP more and 26 mpg. Better response and driveability.
£300
70 ADAPTOR PLATE cast alloy with improved gas flow to counteract engine angle to mount Holley level on your manifold
£150
OR, MODIFIED INLET MANIFOLD -- No ADAPTOR PLATE! centre of manifold machined out and new 70 mounting plate to mount Holley level welded in.
Vastly better gas flow. 20 BHP MORE!
NB. I prefer to modify your own inlet manifold as it will (or should) have been skimmed to suit your heads when they were last skimmed. If I supply you a manifold it may not fit initially and would therefore need skimming or extra gaskets to shim it out.
important Please don't post to me but to the machine shop address you will be given after receipt of your order
£385
MODIFIED INLET MANIFOLD - manifold supplied by Monarch
£435
LO-RIDER AIR CLEANER for Holley. Fits under bonnet - NO bulge
£66
REPLACEMENT FILTER for above.
£19.50
THROTTLE CABLE (adjustable length) plus MOUNTING BRACKET c/w socket attached to cable & ball for carb throttle lever. Full slack adjustment facility.
Manual
£55
Auto
£70
STROMBERG CARBS Original Stag - fully reconditioned, plated and polished with new needles, jets & seals.
important When you receive your new carbs from my supplier, note down what you receive from him and send exactly the same parts in exchange to his address, which you will be given after ordering, not to Monarch. Must be clean and re-usable or the ex s/c will be retained.

NB. In no circumstances will Mk.1 Strombergs be accepted in part-exchange for Mk.2. If we find you have returned Mk.1 carbs and we have supplied Mk.2 then your surcharge will be retained. If you have Mk.1 carbs and you want them re-conditioned you can send them in and we will recon them with pleasure for the same price.
£350
Exchange Surcharge £75



Monarch Stags Ltd: 149 Dunkirk Avenue, Desborough, Northants. NN14 2PP
Phone/Fax: 01536 763778 / 01536 761990 - info@monarch-stags.co.uk