[dieseldude4bt]

I found this on Dieselstop.com: (This Step van is a Grumman Olson on a Ford E-350 chassis. It is powered by Hercules 3.7l Turbo Diesel engine. It has a 4 speed T-19 transmission. This engine provides terrific fuel economy 14-17 around town 17-20 on the highway, depending on load and driving habits" (Excerpt from an eBay listing of a Grumman step van).
I looked up this motor; found the HP was 130....torque I could not find.
weight: 619 lbs.)
100 lbs is not a lot.
If you are doing it for savings it will take a long time to recoup cost and if you count your time as worth anything it may never break even.
But I have had my diesel conversion for 15 years and have no plans of parting with it ever.