Modification of 1600 to 1650 engine?

A 1600 is 69 bore x 85.5 stroke. Using 87 slip-ins will give you 1641. OK in a bug, bad in a bus. Walls are too thin for cooling purposes.

this can be done with changing pistons and new cylinders without any machine work using 87mm or 88mm piston cylinder combos,I would recomend using 87mm because the 88s are very thin walled and tend to overheat leading to oil consumption and loss of compression,however if you are doing a complete rebuild you can have the case machined for up to 94mm pistons that will give you about 2010cc whith the stock stroke on the crankshaft that can be replaced with one up to 86mm rather than the stock