i have a 600hp BBC with a 28 final and 36 STS tires. My problem is i cant get over 6500 RPM. Would 33 BFG solve that or are those to small? and how much more HP would i have to have to turn the 36's?

sure going to a smaller tire will help you get more rrrrrrrrrrs

but let me ask you this....... where is your cam set? what intake centerline is it and is it set straight up, or advanced or retarded?

sean

Don't know your motor details, but yes you should have no problem gaining rpm dropping to 33's.
Math says 28 final 36" tires, 6500rpm equals 24.9 mph wheel speed
28 final 33" tires, 7500rpm equals 26.3 mph wheel speed

I guessed on the rpm gains as it really depends on your motor package. The gain may not seem like much, but you should be able to see that rpm quicker with the 33's which means your building momentum earlier which will help you on the other end of the track.

AP

if you drop down to a 33 yea it will help
but to get a better answer to your question
you might wanna fill in the blank's
what class you running?
for example
600 hp in what typ of class?
auto or manual?
36's are kinda big to be turning
but maybe you could go with 35's and run 6800-7000
now about your motor?
cam? is it set up to go more than 6500
spring's?
compresion
timming?
solid roller or?
there are alot of differnt things to that could cause this
dont just look at tire's