Hi alga, I have been working on fitting my dohc engine, I started from knowing that the scuttle is 260mm above the top rails. I dropped my chassis over the engine and continued dropping it until I had about 10mm to spare between the top of the engine and the scuttle / bonnet level. I was a bit shocked to find that I will only get about 3 1/2 inches ground clearance
The DOHC mates to an MT75, trimming the sump does no good as it is the same level as the bottom of the bell housing.
Speed bumps are a max of 4 inches so a lot of roads will be "no go" areas. The short bumps are the bad ones, at least with the longer ones the front wheels are raised before the sump reaches the bump so clearance is less of an issue.
I think the Pinto is shorter than the DOHC by about 1-2 inches so you should be ok as long as the engine is pretty much as high as you can get it.
Enoch