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3K, 4K and 5K real world performance differences?


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Hi all.

Can those in the know please share their experiences with swapping out any combination of the 3K, 4K and 5K engines?  How noticeable was the upgrade or downgrade?  If I hypothetically took out a 3K engine and replaced it with a 5K engine, how much of an upgrade in performance would I get (not looking for horsepower numbers, just noticeable honest feedback).  How impressed/disappointed were you with the upgrade/downgrade?

Thanks heaps,


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5k swap was so good I did it to two rollas.

Went from holding 100kmh in 4th up a steep local hill with a 3k to accelerating up it on 5th gear with the 5k.

With the competition car a cammed 5k was close to 3 seconds quicker around the local autocross track than the 3k.


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Hi Paul,

           Agree with Colin totally.  Having driven Rollas for 20+ years, I've had 3k, 4K, & 5K engines in my Rollas at different times. They were in combination, with an auto; & 4 speed & 5 speed gear boxes.

The 5K engine, in combination with a 5 speed gearbox, plus a 3.89 ratio diff, is simply the very best setup, without doing the twin overhead cam & Nissan engine swaps.

The only thing that came slightly close to it, was the 4K-U version of the 4K engine, which pumped out more HP than any of the other more common 4K-C engines.

I recently bought a 5K engine, that had been retired from speedway racing, for $ 100.  I've only recently stripped it, & am always amazed how strong the bottom end of these engines are. Just balance them, & they'll spin at high revs all day, without a whimper. 

Cheers  Banjo


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