Why exactly is the first gen of the turbo om617 (.950) 110hp compared the the .951 and .952 which have 125hp?

I've searched the internet and haven't found a definitive answer.

I have one of each and want to make one really good one out of the two. Other than the non egr manifolds, is there anything else better about the earlier om617 than the later two verisons?

Thanks

Camshafts mainly, all 617s after a certain date (Sept '79?) had the valve lift increased. There was also a change in camshaft hardening (late 78?) and so followers can't get mixed up between the two versions. May had been other minor things as well. You also might find a different angle on the oil filter housing but that might be the .951s

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1978 300D, 373,000km 617.912, 711.113 5 speed, 7.5mm superpump, HX30W turbo...many, many years in the making....
1977 280> 300D - 500,000km+ (to be sold...)
1984 240TD>300TD 121,000 miles, *gone*
1977 250 parts car
1988 Toyota Corona 2.0D *gone*
1975 FJ45>HJ45
1981 200>240D (to be sold...)
1999 Hyundai Lantra 1.6 *gone*
1980s Lansing Bagnall FOER 5.2 Forklift (the Mk2 engine hoist)
2001 Holden Rodeo 4JB1T 2WD

Interesting. So I wonder if I can swap out the camshaft to get more power.