3100 aren't bad to do. Forget setting them with used rack components. Incredible waste of time. Great midrange engines though.
3204 and 3304 have to be in the same ballpark dimensionally. The biggest changes being the absence of precombustion chambers and counterbalance shafts on the 3300 series.
One of the perkipillars ran an inline Delphi pump that was also used on some Cummins 300 HP applications. The 320d seems correct for that. They were removed under PIP because of excessive smoke when cold.
The Perkins 6.6 dimensionally would come close to a B model but nowhere near as robust.
3126 are bad for breaking rings. The later revisions WAX, KAL, HEP, SEP like to shed metal from the heui. The pump subsequently fails after contaminating the injectors.
most have made it past this.
Those encompass the early acert.
The C7S isn't bad, its the only regen system that worked for
cat on highway
The injection pumps have a high failure rate, even on the last revision of part number. They are not serviceable without
CAT ET.
From my Not-So-Smart phone