i asked this on the other posting,but is it an overdrive or 1:1 fifth.the 1:1 fifth has two sets of ratios,the standard box is identical to a 1200 4 speed,except there is a ratio between 2nd & 3rd.the option 1 box came with the ratios of 1st 2.676,2nd 1.691,3rd 1.398,4th 1.181.5th 1.000,rev 2.877.the overdrive 5 speeds have 1st 3.513,2nd 2.170,3rd 1.378 4th 1.000,5th 0.875 or 0.825,rev 3.764.the a15 has 35 mm inlet & 29 mm exhaust valves.if it's a 1:1 box,it wont improve it's top speed,if it's an overdrive,it should,as the a15 should have the torque to pull the revs.if it's the standard diff,you could always try for a stock 1200 diff centre,which should lower the revs.by the way,what revs are you pulling at 130k.maybe stronger valve springs would help.have used volkswagen springs from the beetle in an a15,it was a cheaper option than stock gx twin valve springs at the time.