I put a vs 57 on a full load 261. A LOT of fab work. I agree with Pete on compression,but your 250 has a much better combustion chambers than my 261. So you could use a little more compression. 5lbs of boost is worth 2 1/2 points of compression. These superchargers were installed on hot stock motors with no change inside the motor but 100 octane was 47 cents a gallon. Call Craig at Paradise Wheels 760 740 0954 in San Marcos Ca .He is now the factory rep on Paxton and McCulloch superchargers
