If you have better springs then you might be able to take advantage of the Vic jr. but you really have to turn it hard and you will loose some low-end torque.
I have a friend that was running the vic jr and a 600 dp and we changed his intake to a performer rpm and his car picked up about .3 in the 1/4 mile and has a noticeable amount of more low end torque.
The problem he had was that he had the stock springs and the valves would start to float really badly.
Also anytime you turn more rpm's you take more of a chance of breaking something and you put more wear and tear on everything.
I would stick with a dual plane for now until you get a lot more done to your car.
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James Cox
nochevy@hotmail.com
1991 Mustang LX
12.565 @109.38mph 1.764 60ft