Losi TEN SCTE short course truck motor/speedo

[jayropes]

Can anyone help me out with recommending a motor/speedo for the losi s/c truck??
Do i have to go 550 or will a 540 do? is it just the shaft length that is important?
if i do need a 550 has anyone got a combo to swap for a selection of 540's
i have a novac 5.5, a fusion 10.5, a HPI flux 6.5!!

Any help much appreciated as i'm collcting it Friday!!!!

Cheers and Merry Chrimbo