This is the link to the model I used: https://www.thingiverse.com/thing:1911808
Printing the cylinder heads took about 19 hours each.
We printed all of the pistons and connecting rods in one print, this is in gray PLA, the block and heads are in silver. This gives it a bit of contrast.
The total print time for all of the printed parts was about 200 hours. Overall the project took about a month or so from start to finish.