mk1 8v gerabox mod?

Can anybody tell me if its possible to make 5th gear in a standard 8v gti gearbox longer so its more suited for longer top end power with a 2.0 16v installed,instead of running out of steam??

im sure u can just change the fifth gear for a 16v one, but if ur gonna go to the hasstle of stripping the gearbox to do that u may aswell get a 16v box imo.

Thanks  G60rge
I have just sold a good 16v gearbox got no more !
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