I have never tried the 800 but i had 2 of the 750 edelbrocks on my 65 plymouth that weighed 3500 pounds. with my 11.1 440 and a set of box stock edelbrocks 750 carbs i was running 10.50 @ 128 in the 1/4 and that was with out using the nos i had on it at the time. i will be running the same set up on my Indy EZ headed roller camed 440 in my 73 dart. if anybody has a set of 750 Holley dp i could try. i would be more than willing to do a 1/4 mile shoot out between both set of carbs. Mopar65