My GT6 - Future Modifications


My GT6 is still undergoing the final stages of restoration, so any thoughts of further modifications are going on the back burner! However next year I will have inherited a little money from my Dad and may be looking to improve the performance of my car.

However, in the future, when it is running well, I do intend to tweak the engine a little. As it is a 2.5 litre, it is probably putting out around 106bhp of power at 4700rpm and maximum torque of 139 lb.ft at 3000rpm (based on a 2500TC). I would like to increase this to around 150bhp. I have been inspired by Greg MacLeman who has a 1974 Triumph 2500TC which he has been upgrading in the pages of Classic & Sportscar of which he is the Features Editor. What did he do?

Item Work Supplier
Cylinder Head Fast-road top-end rebuild PETER BURGESS - Automotive Performance Engineering, Alfreton, Derbyshire
Camshaft Reprofiled to "Yellow" specification PIPER Cams & Exhausts, Folkestone, Kent
Timing Fitted Vernier Timing gear -
Exhaust Manifold Full stainless-steel 6-3-1 sports system CHRIS WITOR - Triumph 2000 2.5 Specialist ltd, Wookey Wells, Somerset
Carburation Twin SU HS6s BURLEN Fuel Systems Ltd, Salisbury, Wilts
Tuning Set up on Rolling Road dynameter ENGINUITY, London

Cylinder Head

His first act was to send the cylinder head to Peter Burgess for a full fast-road top-end rebuild. According to Greg "(Peter Burgess has) been in business for years and has built many a race winning six", although he is best known for breathing on MG engines.


The camshaft was not replaced, but sent to Piper Cams to reprofile to 'yellow' specification "a grind that majors on usable torque and came highly recommended by pal Matt George and Jason Wright at TRGB.


The fitment of Vernier Timing gear I find a bit puzzling.

Exhaust Manifold

Here Greg used a stainless steel 6-3-1 sport system from Chris Witor. This is on his website as CW3495, but Chris sells a similar version for the GT6 which is PXTH300. However my car is fitted with a Pheonix exhaust system and the Pheonix equivalent I know will fit!


Greg fiitted his 2500 with twin HS6 SU carburettors. I know there can be an issue with these being too big to fit under the bonnet, solved by using Triumph Dolomite Sprint dash tops. However in an email I received from Tony Lindsey-Dean somer time ago, he recommended fitting early TR4 175 Strombergs to my 2550cc GT6 (they have shorter dashpots). Tony used to race Vitesse's & GT6's so he knows exactly what is required! I think it may be easier to adapt the standard inlet manifold to take larger strombergs than SUs.


Here Greg took his car to Enginuity in London. My local equivalent is