How Fast Is A F-350 Turbo Desil?

[BowTie Eater 5 Liter]

My grandpa just bought a brand new 2001 F-350 Turbo Desil, we were going around 40km (20-30mph) & I told him to "PUNCH IT" & the tires squeeled for 1-2 seconds.
this truck is big & fast for a stock F-350.
my dad has a 79 Chev with a 350 & a standard tranny, & i told my grandpa to race him, but he said no because he had to break in the engine (600km's), the ford feels faster when he floors it & wou here the whine of the turbo, but am i wrong?, once he gets back from arizona he will have around 6000km's & then he will race my dad.
anyone know what would be faster?
thanks

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1988 Mustang GT, T-5
No Smog Pump (Shorty Belt), Dumps At The End Of Stock H-Pipe (Sounds Mean), K&N Air Filter (Stock Air Box, Removed air silendcer), 198.9 rwhp @4200 (235 Motor!!), 285 lbs-ft @2900 (336 Motor!!!).
My Stang This Is What Dynomax Ultra-Flo's Do (Soon To Be On My Stang!)