Hi, I have an 88 series 3 petrol with standard diffs and find it a bit undergeared, even with the overdrive I feel it could pull a slightly higher gear.
I used to have a 2 1/4 petrol 88" on standard diffs and 7.50s and felt it could have coped with higher gearing pretty well. If you haven't got and overdrive I would definitely do it.
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