67mustang302

The RPM Air Gap will make way more bottom end torque than the Vic Jr, even with a cam ground to work with a Vic Jr. That's just physics, period. Smaller intakes have higher runner velocity at low rpm relative to a larger intake. It's all where you want the power. Single planes can still make good torque, but a dual plane makes more bottom end and a single plane makes more top end, generally speaking. Typically the pivot point is around 5,000-5,500rpm.

However, it's a 347, so bottom end torque isn't really an issue, if anything softening up the bottom end with a larger intake might make it more manageable on the street. Which one it gets down the track with faster....who knows. It's going to depend on the rpm range the engine operates in dictated by transmission gearing, and what the total power across that range is. That's why companies like Lenco and Jerico offer several hundred different gear ratio combos for their transmissions, so you can match gearing to engine power bands.

If you're worried about going fast just put the Vic Jr on it.

symonds86

i took yer guys advise and did a lil more research ad i am pretty sure im going with the vic jr

symonds86

i dont mean to beat a dead horse by bringing this up again but, i went to a local machine shop today that is known for building some very nice performance sbfs. they recommended a performer intake fr my motor since it will be more street driven. they said that will take away some top end but keep the power where i want it on the street any thoughts?

67mustang302

Again, it depends on what you want. The Performer is just too small for a 347 all the way around. A larger stroker like that needs a bigger intake, and chances are it'll make more bottom end with the RPM than it would with the regular Performer, just because the performer will strangle it. If you want more bottom end power then I'd go with an RPM, if you want more track performance then go with a Vic Jr.

The Vic Jr. will still make good bottom end torque on a 347 and good top end power, the RPM won't make quite as much peak hp, but will still be fast and have a little better part throttle response at low rpm and make more bottom end torque(which may or may not be a good thing). The RPM will get better mileage, if that's even a concern.

I'd stay away from the Performer on a 347 though, unless it's got a tiny cam and you're gonna use it to tow.

symonds86

ok thanks, i don't plan to tow with it and the cams not small so no performer. i guess right now im looking for that middle ground good on the street but decent at the track. i'll give up some peak hp for streetability. later on when the car become more of a track i can always change it.
thanks again