Straight cut or dog box

[rww]

I am building a new engine /gearbox over the winter for a third year of sprinting.

What is the informed opinion of the best gearbox to use - straight cut synchro or the ultimate , but very expensive, dog engagement gearbox? Engine will be around 125 bhp.Appreciate your views, gents.

Edited by rww on Thursday 16th November 13:24

[rww]

Thanks gents. All very useful. Spec. of engine will be 649(or similiar) cam , steel flywheel/backplate, forged 73.5mm pistons, 45 Weber, and the usual race inlet/exhaust manifolds probably on a 3.9 or 4.1 final drive ratio.

Current spec for last two seasons has been 1.5 ratio rockers, 286 cam,MG Metro head with limited mods by Swiftune, std 1275 Metro crank, rods , pistons, lightened flywheel/backplate on std drop gears and gearbox and 4.1 FD.With 45 Weber this produced around 105bhp at Gerald Dale's RR and revved to 8000 rpm (chrono r/c) with no driven waterpump (electric) or alternator.The flexibility of the cam allowed us to virtually use only 3rd and 4th gear at most circuits. Pulled just over 7000rpm in 4th at Goodwood Lavant Str. (with a slight misfire) which, I think, is about 95mph.

Any contributions/opinions appreciated.

Edited by rww on Thursday 16th November 15:55

[rww]

Thanks Ken, Gareth et al.

Another expensive item to put on the Christmas list !