455 Olds Vaccuum or Mechanical Secondaries

[vidrinek]

I would like some input on whether a carb with vaccuum or mechanical secondaries would be better on my jet boat. Its a mild 455, Offy tunnel ram. Thanks.

[rivercrazy]

Go with the Mechanical Secondaries. They will open sooner and your accel will be much stronger.

[rmclague]

I run 600cfm vacum secondaries
Mine is also a mild 455 with offy tunnel.
I was advised to run the vacums by more than one individual in the know.
I we were running built mills with mucho ponnies the additional fuel early on would be great but its probably way to muck for the horsepower we are making.
a pair of smaller double pumpers say 450cfm
jetted right might be a good choice?
Originally posted by vidrinek:
I would like some input on whether a carb with vaccuum or mechanical secondaries would be better on my jet boat. Its a mild 455, Offy tunnel ram. Thanks.

[AMCWNOS1]

I USE AN 850 VAC SEC ON MY 455OLDS . IT WORKS GREAT. PULLS ALL THE WAY UP TO 54OORPM,S