383 SBC?

[Old Buzzard]

A couple questions for anyone with the 383.
Engine is a 10:1, Edelbrock alum heads, mild cam, Holley 750, MSD dist/coil/6A box, headers.
In a 55 sedan.
4L80E trans, with lock up.
The owner is insisting on running what I consider "weird" timing values.
Seems his engine guy has told him to run timing @26* @ 3000. Lock it down, and drive it.
The owner is reporting 8-11mpg.
My observations include the ceramic coating, on the header tubes has turned dull, near the heads.
A couple plug boots are toast, etc.
[The headers were recently coated].
I've advised him that 26*, at road speeds of up to 80mph, is too low.[Engine rpm at/near 3K].
After all the background info, the ?'s
1. What are you running for initial and WOT timing?
2. At what rpm do you see max timing?

I've been doing this for a looonnng time, and totally disagree with the tune specs.