I am far from a gearbox specialist so I'm going tohave to seek advice on this matter.

I know that syncro gearboxes generally don't like fast gearchanges, made worse by high revving engines from what I am told so I am looking for I presume a dog box.

The car is track only/sprint based, VERY little road use so not bothered at all about noise and how much of an arse cruising the town centre will be with one.

I assumed all dog boxes used straight cut gears but it would appear not, what exactly is the benefit of helical over straight cut in a dog box or even semi helical ? I was under the impression a dog box could atleast be used atleast on upshifts without a clutch and downshifts if you match the revs but does that depend on the type of gears the box has ?

Someone please explain it to me as I honestly need to know whats what with these boxes.

For reference if it makes any difference its a 275hp (max) NA engine with a 9500rpm rev limit, fitment wise unless its a Type 9 is going to require a bellhousing being made but I am prepared to do that if it came to it.

Gearbox suggestions are welcome, currently looking into a Glebe unit, T5 based but haven't rung up to find out the specs, I'd rather have half an idea what I'm talking about before I call than waste the guys time if its no good to me.