How slow is a non-turbo 300td?

[Mike Rancourt]

This is my only experience with a non-turbo, so my question is, how slow is this thing supposed to be? What is normal?

I have a friend with a 1980 300td (wagon, nonturbo), and it's slow as f**k, so I have been working on it here and there to see what I can do.

It's got a ridiculous WVO "conversion" with a nest of hoses going everywhere, oozing (biodiesel) fuel lines (I have replaced most of them under the hood), a sh***y heat-exchanger for the veggie, a rather large Racor spin-on for the veggie, but everything also runs through the stock filter, and I think it has a looped fuel return, but there are crazy T connectors that make it impossible to trace the fuel supply and return paths according any form of logic I have come across in the 6 or so WVO vehicles I've played with over the years (probably 20 configurations on 6 vehicles because I like to try things). So, she runs biodiesel most of the time, but there's no difference in performance between that and WVO (she never runs petro-diesel).
One day, I changed the Racor and most of the supply lines under the hood and she saw a marked rise in performance, but it lasted only a few days and returned to normal.
Later, I changed the stock fuel filter, and it got a little better, but it still wouldn't make it above 45 mph in a half mile straight-away with a slight downward slope.
Today, I did some other things which require some back-story:
There was one 3/8" fuel hose connected to a 1/4" fitting on the stock filter!
There was one 5/16" hose connected to a 1/4" fitting on the stock filter!
There was one 3/8" hose connected to a 5/16" fitting in one of those mysterious T's I mentioned above, so I figured changing those things would help, and I think maybe it did a little, but I took the car on the freeway with my foot to the floor and couldn't get over 60 mph in two miles, dipping under that at the slightest hill.
This is my only experience with a non-turbo, so my question is, how slow is this thing supposed to be? What is normal?
I would also ask about the shifting. By the time I reach 25 mph, I am in 3rd gear and not accelerating very well - not that 1st and 2nd are that awesome, either. Is this normal shifting? When I go down to 2nd manually, I can get a little kick, but as soon as I go back to 3rd, it just sort of acts like it would rather have stayed in bed (this car doesn't drink coffee).
Yep.