The generation that Titan ran (3rd generation, 1982-1992) generally ran the 5.0 (305ci) V8 for the Z28, the IROC-Z came with the 350, but even that was only rated at 215hp-250hp depending on year. Some quick 0-60 numbers for the various Z28s of that generation:
1982 Chevrolet Camaro Z28 9.7
1983 Chevrolet Camaro Z28 H.O. 6.7
1985 Chevrolet Camaro IROC-Z28 7.0
1990 Chevrolet Camaro Z28 6.5
1992 Chevrolet Camaro Z28 6.7
The '98 Z28s ran 5.2 0-60 and 13.6 in the quarter. The '82-'92 ran 15.0-15.2 in the quarter when new.
So stock and in tip-top shape they should've run pretty equal, but that one he was racing likely had a tired 305 or possibly a 350 with a power-sucking automatic, there was no contest.