Performer RPM ?

[Ole Blue 68]

Is anybody out there running an RPM Intake and Cam combo? If so, how do you like it and how is the idle? Rough for street use?

[Ole Blue 68]

Nobody's running this combo?

[Ole Blue 68]

Guess not... alright, here's the specs on it. Anyone care to weigh in on it?

Cam Style: Hydraulic flat tappet
Basic Operating RPM Range: 1,500-6,500 RPM
Intake Duration at 050 inch Lift: 234
Exhaust Duration at 050 inch Lift: 244
Duration at 050 inch Lift: 234 int./244 exh.
Advertised Intake Duration: 308
Advertised Exhaust Duration: 318
Advertised Duration: 308 int./318 exh.
Intake Valve Lift with Factory Rocker Arm Ratio: 0.488
Exhaust Valve Lift with Factory Rocker Arm Ratio: 0.510
Valve Lift with Factory Rocker Arm Ratio: 0.488 int./0.510 exh. lift
Lobe Separation (degrees): 112
Intake Valve Lash (in): 0.000
Exhaust Valve Lash (in): 0.000
Computer Controlled: No
Lifters Included: Yes
Lifter Style: Hydraulic flat tappet

[JAKES 68GMC]

ttt

[see ten]

I personaly run the performer on both of my trucks. I just thought that they were more suited to the RPM range I would be running.

[72MARIO]

I have the RPM intake on my 355 with the 327/350 Hp cam. It works great.

Not sure on the cam in that kit. Just make sure you have the power in the range where you will be driving most of the time. It's no good it your making 375 hp at 6000 when you cruize at 2000 and make 150 hp in that range.

[Ole Blue 68]

Well that was my concern since the performer's range is supposed to be idle to 5000 but I figured the rpm should be ok since its range starts at 1500 and even though I don't have a tach, I know i spend a lot more time at 1500 then i do at idle.

[70rs/ss]

What you need to do is search the flow rates on your heads. If your heads stop flowing air at .400 lift, then why put a .425 or .450 lift cam in it. You cannot pick a cam by its advertised RPM range, as this is an estimate. There are websites that post common chevy heads and their flow numbers. carcraft.com has flowed many different heads and created a chart. Without the cfm flow numbers you are guessing at best when it comes to picking a cam. Scoggins Dickey has some flow numbers for popular SBC nad BBC heads. Flow numbers usually start at:
.050 lift 25cfm
.100 lift 50cfm
.200 lift 65 cfm
.300 lift 74 cfm
.400 lift 85 cfm
.500 lift 86 cfm
.600 lift 83 cfm

Look for the most cfm and then look at the lift, if the max cfm is at .500 lift and it is 2-3 cfm lower at .400 lift, then it is obviously better to go with .400 lift as it is easier on valve train. If you want you could go with .450 ish and not really lose anything. This is the ONLY way to pick a cam, period. Once you know flow numbers you can pick the lift and have a good performing engine. If you ar e sreious, find someone with a flowbench and have you heads flowed, if you have paid for port work and they didn't flow the heads, how do you know they helped the heads? A flow bench is the only way to verify how the heads work, new perf heads all list those numbers upfront, even the out of the box Vortec heads offer flow numbers. without knowing how much air your heads move you are guessing (at best what cam to buy) and more often than not we buy cams that are too big (too high of lift) and that hurts performance. I'd put a well matched small cam combo against the same motor running a too high lift cam any day, because the motor that has the correct cam to match the flow characteristics of the heads will flow the correct amount of air and not slow it down by opening the valve to far, and it will not wear out springs, etc from excessive lift. My .02 cents, but if you do not believe me, look into the cam manufactuers sites and talk to a tech, if they know what they are doing they will tell you the BEST way to pick a cam is to know the flow numbers and then the other stuff, ratio, trans, stall, etc. Good luck

[Novaguy73]

Originally Posted by 70rs/ss

What you need to do is search the flow rates on your heads. If your heads stop flowing air at .400 lift, then why put a .425 or .450 lift cam in it. You cannot pick a cam by its advertised RPM range, as this is an estimate. There are websites that post common chevy heads and their flow numbers. carcraft.com has flowed many different heads and created a chart. Without the cfm flow numbers you are guessing at best when it comes to picking a cam. Scoggins Dickey has some flow numbers for popular SBC nad BBC heads. Flow numbers usually start at:
.050 lift 25cfm
.100 lift 50cfm
.200 lift 65 cfm
.300 lift 74 cfm
.400 lift 85 cfm
.500 lift 86 cfm
.600 lift 83 cfm

Look for the most cfm and then look at the lift, if the max cfm is at .500 lift and it is 2-3 cfm lower at .400 lift, then it is obviously better to go with .400 lift as it is easier on valve train. If you want you could go with .450 ish and not really lose anything. This is the ONLY way to pick a cam, period. Once you know flow numbers you can pick the lift and have a good performing engine. If you ar e sreious, find someone with a flowbench and have you heads flowed, if you have paid for port work and they didn't flow the heads, how do you know they helped the heads? A flow bench is the only way to verify how the heads work, new perf heads all list those numbers upfront, even the out of the box Vortec heads offer flow numbers. without knowing how much air your heads move you are guessing (at best what cam to buy) and more often than not we buy cams that are too big (too high of lift) and that hurts performance. I'd put a well matched small cam combo against the same motor running a too high lift cam any day, because the motor that has the correct cam to match the flow characteristics of the heads will flow the correct amount of air and not slow it down by opening the valve to far, and it will not wear out springs, etc from excessive lift. My .02 cents, but if you do not believe me, look into the cam manufactuers sites and talk to a tech, if they know what they are doing they will tell you the BEST way to pick a cam is to know the flow numbers and then the other stuff, ratio, trans, stall, etc. Good luck

Im going to have to disagree if i read your statement correctly. The way i took it was you say that Lift is the most important factor in picking a cam. I saw nothing about adv duration, .050 duration or Lobe seperation. Id say first and foremost that I agree that you dont need .600 lift if your heads dont flow up there. Its pointless and probably hurts performance.
But simply put Advertised duration is also a huge factor. This is what will determine your cylinder pressure for a given static compresson ratio. too big a cam and your motors a slug down low, too small a cam and you have detonation issues and a cam that is far from optimal. Lobe seperation is important to say the least. If you want a scavenging effect, a peaky HP/TQ range and an idle like a pro stocker {My Nova} you go with the tighter 106,107,108 somthing around there. Now if you get in the 112,114 range you will have a broader power range a smoother idle and are better suited to run a power adder. These are other things to take into concideration way before you pull your heads off and have them flowed.

As a side note, IMO most manufacturers lie about head flow but without flowing them all this will be your best bet if you want to pick a cam based on that. I have found through study that AFR and Brodix are the only 2 companies that dont inflate #'s, Brodix is actually conservative. Hence the reason i chose their race rite 200 heads for my nova.

[Ole Blue 68]

Must...stop....reading.....Getting....dizzy.....Too...much...information....

Just kidding...

I'm going with the Lunati. If it sucks, I'll pull it.

[72MARIO]

It's the cruize speed that matters you want the truck to have power starting around 800-1000 that way you have the bottom end power you most likely need.
Unless your using 4:11's and running in the 1/4 mile at 6500rpm, the Performer setup is better for the street. We all want to say we have a massive cam and 500 HP but at what RPM ? The key is getting the power in a range where it actually get's used.

All I have is the intake on my motor the cam is mainly what controlls what rpm the power is made. Low end power is best for economy and driveability.

[Ole Blue 68]

Good point Mario. The other thing I would be concerned about would be whether my 600cfm carb would be enough with that combo or would i need to bump up to a bigger carb.

[72MARIO]

500cfm is enough for a 400hp motor jetted correctly. A 600cfm will be fine. You can go bigger but it's not necessary. If you put in a huge cam (Which work great at high RPM that's what Race cars have them and sound that way)
You might need to increase the jet size.

[Ole Blue 68]

Yeah this is true. Well I reconsidered on that RPM cam and I'm going to go with the milder Performer cam instead. Thanks for the good info!

[MrC1]

You didn't say what size engine this is for.

Either way those duration figures are a bit stout. Normally big block truck engines run about 220* of duration and the SBs a little less. The lobe separation isn't bad, however.

I'd check out the Edelbrock dyno sheets for the different combos. Look carefully at the torque curves. You're going to want as much down low as possible with the flattest curve you can get.

You could also plot the combos in Dyno 2000 or something similar to get a better idea.

[Bowtie67]

The Edle cams are old school, go with a Comp Cam, Crane, Crower etc. the RPM cam unless you have some good CR it will run just OK, till I meet up with you at the light and leave you like you have an old Iron Duke 4CYL..

[Novaguy73]

Please post your combo in detail here include your compression ratio.

Both edelbrock cams are crap in all honesty ill give a reason why. With the RPM you have 308/318 degrees of advertised duration. You really need at least 11:1 maybe 12:1 compression for that to work worth a hoot. Then the .050 duration is only 234/244. That is a TERRIBLY slow ramp and you would be leaving alot of power to be had. If you want me to explain this in serious detail i can.

Call up a few major cam companies and get some responses on your combo. But i will guarentee you that youde be leaving TONS of torque and at least 20 hp and some gas mileage on the table by running an old ass Edelbrock cam.
Call Crane, cam motion, erson, bullet, crower, howard, isky. Actually i would call Lunati about their new Voodoo cams. Harold Brookshire designed them so you know they are good. He used to own Ultrdyne cams and designed comps HE line 20 yeas ago. Call Lunati for sure....but DONT GET THE EDELBROCK CAMS....

[72MARIO]

I also did not like there 1406 carb on my 84. I love my Demon it's like a holly but diffirent.

[junkyardjohn]

BEFORE YOU INVEST IN COMP. CAMS , MAYBE YOU SHOULD TALK TO SOME OF THE MANY MANY PEOPLE WHO'VE HAD THEM GO FLAT IN LESS THAN 1000 MILES. JOHN

[Ole Blue 68]

Thanks John, I've seen a couple posts on the site that didn't have good things to say about Comp Cams so I'm staying away from them.

Originally Posted by junkyardjohn

BEFORE YOU INVEST IN COMP. CAMS , MAYBE YOU SHOULD TALK TO SOME OF THE MANY MANY PEOPLE WHO'VE HAD THEM GO FLAT IN LESS THAN 1000 MILES. JOHN

[Novaguy73]

Originally Posted by junkyardjohn

BEFORE YOU INVEST IN COMP. CAMS , MAYBE YOU SHOULD TALK TO SOME OF THE MANY MANY PEOPLE WHO'VE HAD THEM GO FLAT IN LESS THAN 1000 MILES. JOHN

I would stay the hell away from the comp XE line specifically. Go over to the chevelle or camaro borad and just ask. Some people swear by them, some swear AT them.

[Sonny's at Work]

I have a RPM manifold/w1406 and I am not to crazy about it myself (PO installed it). I would have gone with the regular performer/performer air gap if I had to do it again. I have a 350/700R4 w/3.73 and I rarely see over 4,000rpm. Most of my driving is around the 1500-2200 rpm range. Look for a combo the suits the majority of how you plan to drive the truck.

Sonny

[Ole Blue 68]

So you think its the intake and not the carb? You're the first person I've heard from who disliked the RPM intake but i've seen tons of posts from people who didn't like the 1406.

Originally Posted by Sonny's at Work

I have a RPM manifold/w1406 and I am not to crazy about it myself (PO installed it). I would have gone with the regular performer/performer air gap if I had to do it again. I have a 350/700R4 w/3.73 and I rarely see over 4,000rpm. Most of my driving is around the 1500-2200 rpm range. Look for a combo the suits the majority of how you plan to drive the truck.

Sonny

[400ex]

My .02..

No experience with edelbrock cam. But I have been running a 625 cfm Carter for a couple of years (which is basically the same design as an Edelbrock carb) with a Comp Cams XE274. Motor was built by a professional and dynoed at 390 hp. I 've got around 10,000 miles on it and it runs great. No its not the fastest thing in a truck but it does move and somewhat quickly.. I am pleased.

[sweet n rare67]

Well, I have The Performer RPM cam and Performer EPS Intake and reworked heads. So far I like it pretty good but I have had No Street time on this setup so I will see. I didnt know so many people hated Edelbrock Cams.