ok i have a carbed small block and have dart iron eagle heads 210cc runners i think, .515/.515 lift cam,750 dp... the intake i have on there now is a performer rpm but my buddy has a victor jr. intake i can put on there... the cam is a hydraulic roller and it says its only good up to 6500 rpm....now my question is will it help or hurt me to put that intake on instead of the performer rpm?????

thanks for all that can help

 

IMO unless you have gears above 3.73s and a good stall to keep your rpms up pretty high it's gonna hurt you slightly. If you are running a typical street set-up with 3.08s to 3.42s and a 700r4 then I would think you would want to stick with the RPM manifold.

 

i have 3:73s in back with a th400 trans that has a 3200 rpm non lockup stall....now what do ya think???

 

bump ^^^^^

 

I'd say that intake will compliment those high volume heads a lot better than the RPM intake.

 

I agree with IROC22.

It's at least worth the effort to find out. Do you have a baseline with your car now in the quarter mile. I wouldn't do it without haveing a tangible way of finding out if it made a difference.

 

ummm actually no i dont .....but my buddy thinks the rpm intake is holding me back...

 

If you have a roller cam with .515" of lift, it's not a high RPM cam. It's probably about 220° @ .050", which would put its torque peak in a 350 at about 3900-4200 RPM and HP peak at around 4800-5000 with the rest of that combo.

Stick with the RPM, or get a cam that matches the rest of your combo better.

 

actually i have a 406.... and the cam says its good up to 6500 rpm.. so now what do u think???

 

the more cubes you have, the smaller the cam seems.



id put the vic jr on anyway though..... its not going to hurt your 400 as bad as alot of people here like to imply ( and alot of them have never even had a vic jr)

athough id also put a bigger cam in too...

 

this winter im going to put a solid in it ....and do some other stuff too... thats the main thing holding me back...

 

Typically, a given cam will produce peak volumetric efficiency at about 8-10% lower RPM in a 400 than a 350; so I'd put your peaks at something like 3600 RPM peak torque and 4600 HP with the existing cam. Even farther out of the range for taking advantage of the bigger intake.

The "RPM range" of a cam that a manufacturer gives is utterly meaningless, except as a guide for buyers that have no other benchmarks to guess at the match of a cam to their application. Kind of reminds me of a certain otherwise reputable manufacturer that rates one of their intake manifolds for use from "idle to 7200 RPMs". Now just exactly what does that mean? That: yes an engine with this intake will idle and yes it will run 7200 RPM if not otherwise limited; or does it mean that out of that manufacturer's entire product line, it idles the best and produces the most power at 7200 RPM; or that the engine's torque (volumetric efficiency) is within some usable value, say, 75% of its peak, from idle to 7200 RPM; or what?

Then on top of that, you haven't told us what the car weighs, what gears are in it, what converter you run, whether it's a street car or strictly race-only, how fast you are going now and would like to go instead, what RPM you shift at, etc. etc. etc. All of those things influence how you set the motor up.

I can tell you though, the Vic Jr. won't make the car faster (produce more power than the RPM) except at RPMs above 6000 or so. At any RPM below that, the RPM will go faster. So if your RPMs go below 6000 during a pass, the Vic Jr. probably isn't for you.

Go do a couple of dyno pulls and see where the car makes its power now. Get yourself a baseline to start tuning from. Then you'll have a solid reference to compare to after you make changes.

 

thank you for all your help im staying with the rpm for now until i change my setup...and i usually shift my car @ 6000-6500 rpms...