Paul,  Any suggestions on what I should do differently to run my 7 in a
3 hours enduro, and if I survive and the car survives that, a 6 hours
enduro later in the yr, that I don't do for regular SCCA 45 min
race?     Thanks,  Dave D

Endurance racing is all about testing, preparation and
logistics. Can you find a track where you can run it
flat out for three hours?

Plumbing and electrical must be top quality.
I would install electric fan cooled heat exchangers on
the dif and tranny. Does it have a dry sump system? It needs one.
Also you are going to need at least one complete set
of all spare suspension and body parts. We lost a 24 hour in Daytona
while leading the race by 19 laps because we did not have
a spare rear A arm. Phil Hill driving.

BTW It took GM years to get the V8 to last 24 hours
on a Lemans lap programmed dyno. They ran the engine until it
failed and then redesigned it, built a new one and started over.
They wound up by compromising the HP and the redline.