Big block 383 build!

If anyone thinks that the stock manifold won't make much difference, perhaps our testing might change their mind. Here are the airflow figures for a Edelbrock Performer RPM cylinder head and the same head, same port with an 850 Demon carburetor and 5 different intake manifolds, including a FACTORY CAST IRON INTAKE from a 1969 383 Road Runner.

1) mild touch up on a RPM Performer Head, no carb, no manifold
2) same head with an 850 cfm Demon carb and FACTORY IRON 4-BBL intake from a 1969 Road Runner
3) 850 Demon and RPM Performer intake
4) 850 Demon and Torker II intake
5) 850 Demon and M1 Single plane
6) 850 Demon and 383 Victor

Lift...........1...........2..........3.........4.........5..........6

.100........72..........69........71........71........72........72
.200.......150........131......145.......148......148.......150
.300.......212........172......195.......201......201.......202
.400.......254........187......228.......242......234.......240
.500.......276........199......240.......254......254.......261

.600.......290........203......251.......264......266.......271
.700.......302........204......256.......269......273.......280

Lets not even consider .600" and .700" lift right now. If you use what might be the best street dual plane manifold availabe now, the Edelbrock RPM Performer, you will gain 14 cfm @ .200", 23 cfm @ .300", 41 cfm @ .400" lift and 41 cfm @ .500" lift.

Will the stock manifold work? Sure. Will it be as good, on a mild engine build, as a good aftermarket aluminum intake? NEVER!