E30 Zone

I'm currently doing a m30 conversion with a m10 gearbox am I right in thinking that a m10 prop will fit straight on with no modifications?

False. M30 engine + M10 Gearbox + M20B20 prop + M20B20 gear linkage = SUCCESS (I've done that recipe twice now)

I'm 99% sure the M10 prop is not the same length as an M20B20 prop, therefore M10 prop is not a direct fit.

Thanks for the reply I will get a m20b20 prop I take it I can't use my 2.5 linkage?

I believe 320i and 325i linkages are different lengths but I know that 320i linkages are the direct fitment, as such 325i linkages shouldn't work.

Ok cheers mate ☺

rob0r is right b20 prop and b20 linkage as the gearbox is slightly shorter. The m10 prop is 4 mm to short or too long. Can't remember what way but its definitely 4mm

Depends entirely exactly where you fit the engine. Not into ancient history, so I know very little about fitting these engines, but IIRC, there are three fitting positions used.
The gearbox mountings on an E30 are infinitely variable over about a distance of a foot, so you can't decide linkage or prop from the gearbox type.

That's true Brian but 99% of M30 swaps these days use just one position, the one that puts the engine furthest back which I believe is "position 3". On Lee's mounts there is only position 2 and 3, and using anything other than position 3 would mean the radiator would have to be mounted well within the front panel which would be highly unusual as neither the E28 535i or E34 535i radiators could be used.

M30 engine + M10 Gearbox + M20B20 prop + M20B20 gear linkage + position 3 = SUCCESS!