Performer RPM intake and CAM question?

[Tepot]

HI,

I am looking in changing the cam shaft in my L-48 engine. I was looking at the Edelbrock performer RPM and they say it works really good when it's paired with the Edelbrock performer RPM intake.

I am willing to change both parts. But before I do. I need to know if it works good. I would like to have a bit of a Rouph idle. I've recently installed some flowmaters 40 series on headers dual exaust no CAT and it sounds good but not enouph for me. I would like a cam shaft that would ilde rouph a bit that would make my car sound really good.

So the question is. what kind of idle does the edelbrock performer RAM cam as? is it smooth idle or rouph idle?

Consider I put the performer RPM CAM and INTAKE. how much horsepower will I gain over stock? I drive mostly highway but I really want my car to sound like it as alot of power in it.

let me know what you guy's think

Thanks
Daniel

 

[AdvancedAutoCC]

RPM packages is good, BUT.....

HI,

I am looking in changing the cam shaft in my L-48 engine. I was looking at the Edelbrock performer RPM and they say it works really good when it's paired with the Edelbrock performer RPM intake.

I am willing to change both parts. But before I do. I need to know if it works good. I would like to have a bit of a Rouph idle. I've recently installed some flowmaters 40 series on headers dual exaust no CAT and it sounds good but not enouph for me. I would like a cam shaft that would ilde rouph a bit that would make my car sound really good.

So the question is. what kind of idle does the edelbrock performer RAM cam as? is it smooth idle or rouph idle?

Consider I put the performer RPM CAM and INTAKE. how much horsepower will I gain over stock? I drive mostly highway but I really want my car to sound like it as alot of power in it.

let me know what you guy's think

Thanks
Daniel

The Performer RPM cam/intake package is a bit on the aggressive side for a daily driven streeter. The idle is rough like you want, but the vacuum at idle may not be enough for the power brake booster (you'll have to plumb in a vacuum reservior in that event). In addition, you'll need to replace the stock valvesprings as they won't have enough seat pressure for the camshaft profie of the RPM series. Also, using the RPM package with the OEM heads and Q-jet is a colossal waste of time and money. You're best served to utilize the Performer RPM heads, as they're designed to work together with the camshaft/intake. The carburetor needed would be either a Holley 750CFM double pumper (preferred) or a 750 CFM Edelbrock.

The Performer RPM is a "hot street" type setup, meaning it's not a simple "stick in the cam and go" deal. You have to think "big picture" before changing a camshaft. If all you're looking for is a rough idling slug, then just throw the cam in....but be prepared to have LESS available power, and a loss of good street manners.

Good luck!

 

[waterboy1976]

Ive got that cam/intake setup with the air gap one though. It has that rump rump rump idle sound youre looking for...Enough vacumn for headlights as well as brakes. Ive got it with 40 series flowies too and they seem to pop a lot....looking at going with 50s to eliminate the pop....Heads: Dart Iron Eagle 180 cc runners with 64 cc chambers shaved. Carb: mighty demon 650 (or Holley) thats my setup with the rpm cam/intake....using stock heads may be a waste of the cam....Qjet carb can be upfitted nicely to run with that intake and cam setup...

 

[Tepot]

Ok. seems to be a bit complicated.

If I only want to change intake and cam and don't want to touch anything else. Is there a cam somewhere that you guy's recommend. I'd like a cam that rouph idles but won't need too much changes.

I have a performer intake from edelbrock right now.I would'nt mind to stay with this one but i'm interessted to swap it for an edelbrock intake with PermaStar finish or maybe just polished.

I really don't know what would be good for me. I'd like to put a nice polished look intake and a nice good rough idle cam without modifying too much things on my car.

 

[Hib Halverson]

HI,

I am looking in changing the cam shaft in my L-48 engine. I was looking at the Edelbrock performer RPM and they say it works really good when it's paired with the Edelbrock performer RPM intake.

I am willing to change both parts. But before I do. I need to know if it works good.
(snip)

let me know what you guy's think

Thanks
Daniel

The Performer RPM intake manifold and camshaft package will certainly make the engine idle rought and make people think you have lots of power, however, that's about all it will do.

The problem is that just the Perf RPM and the cam are a poor match to an L48. The engine will have poor low-end performance and run well up high.

What you need to do, in addition to adding the Performer RPM pieces is increase the compression to 9.5-10:1, have the heads treated to a "street high-performance port/polish" and larger valves, install headers and a low restriction exhaust. Do all that and then you'll be making the 375-400hp the Performer RPM package can make.

Oh...one more thing, you need to change hoods because the Perf. RPM intake won't fit under the stock hood.

If you don't want to make all those changes, I'd opt for the Edelbrock Performer manifold and cam which can be used with the rest of the engine, as-is. Then...

... if the idle isn't rough enough, I'd set the idle air-fuel ratio just lean enough to cause a slight misfire.

 

[Tepot]

If you don't want to make all those changes, I'd opt for the Edelbrock Performer manifold and cam which can be used with the rest of the engine, as-is. Then...

... if the idle isn't rough enough, I'd set the idle air-fuel ratio just lean enough to cause a slight misfire.

OK. well basically I don't want to put to much money in this. so right now I have already the performer intake on my L-48.

Is the performer Cam considered smooth idle or rouph idle? I can't find anything on edelbrock website that tell's me if it's smooth idle or rouph idle.

And how many Horsepower will I gain over stock with performer intake and cam?

 

[Tepot]

Is the performer Cam considered smooth idle or rouph idle? quote]

Well I guess I've found the answer to my own question. I've been looking for the performer plus cam on www.summitracing.com and they said "They feature smooth idling cams for daily drivers" for the performer plus.

so guess what. smooth is not what i'm looking for.

So if Edelbrock can't help me , who can? Do you guy's know any cam that would rouph idle in my engine without having to do too much modifications?

should I go with the L-82 CAM or even the LT1 Cam. is there a GM cam for my engine that idle's rouph?

 

[craig32]

Dan,
Be careful here. The camshaft is not just a bolt on accessory. If you put in a cam with more lift, you should have the heads to take it. You're also increasing the volume through the engine and should consider bigger pipes to take it away. Putting a new bigger cam in an older engine without going over everything is not a good idea. You would also need new cam bearings, meaning pulling the engine out and apart. If the engine hasn't been rebuilt recently, the older rings are going to take a beating with more air/fuel intake.
This isn't an issue with a Corvette, but taking a two barrel engine and changing intake and carb without changing heads and cam is a waste of time and money. I've also heard many say some companies parts don't match well with others, hence writing one company a big check for everything. Be careful what you wish for, you just might get it.

Craig

 

[glen242]

Tepot:

If you don't care about performance, only sound, pull a spark plug wire off before you pull into the drive-in. Plug wire off will give you the rough idle you are looking for.

Or do what Hib Halverson suggested.

 

[kiwi vet]

Tepot:

If you don't care about performance, only sound, pull a spark plug wire off before you pull into the drive-in. Plug wire off will give you the rough idle you are looking for.

Or do what Hib Halverson suggested.

Another cheap option!

Put a manual choke cable in, and pull it out once the car is at operating temp when you are idling, and it will sound nice and rough!!!!

Grant
Sorry couldnt resist!!!!

 

[Tepot]

Ouf !!!. Thanks for all the info guy's. My Engine was rebuilt before it was sold to me. The engine runs great. The only thing is. If I want it to sound good or get more power. I think it would be cheaper for me to buy a crate engine.

I was looking at the price for edelbrock Performer RPM Heads, intake, Cam and Carb and it will cost me alot of money and I will still be stuck with my old engine.

A crate engine will cost possibly the same or just a bit more and will be brand new and will come with a warranty as well.

Darn. I don't know what to do now?

 

[Jack]

Performer & RPM heads are same ...EXCEPT ... the RPM has NO exhaust Xover ... NO Xover is a good thing for most.

For most folks: Performer cam is too small ... RPM cam too big.

Plain performer intake (not RPM) will work just fine with RPM heads and a good cam ... it'll work well with your Qjet too ... and it'll fit under the hood.

If your your '74 L48 still has its low compression dished OE pistons ... Suggest:
RPM heads (64cc)
Your current performer (2101) intake
Your (freshened & tweaked) OE Qjet carb
Your (freshened & tweaked) OE distributor
hydraulic flat tappet cam & lifter similar to these: SpeedPro/Sealed Power P/N KC-1013R or Summit P/N SUM-K1103 ... ~.443"I/.465"E valve lift ... 214*I/224*E duration @ 0.050".

With all the above: Static CR result will be about 8.8:1 to 9.1:1, make about 315HP/360TQ at flywheel, will have good vacuum & street manners, but will lope. G'Luck!
JACK:gap

 

[glen242]

Ouf !!!. Thanks for all the info guy's. My Engine was rebuilt before it was sold to me. The engine runs great. The only thing is. If I want it to sound good or get more power. I think it would be cheaper for me to buy a crate engine.

I was looking at the price for edelbrock Performer RPM Heads, intake, Cam and Carb and it will cost me alot of money and I will still be stuck with my old engine.

A crate engine will cost possibly the same or just a bit more and will be brand new and will come with a warranty as well.

Darn. I don't know what to do now?

You better check out the sound of the crate engine before you buy. It might be too smooth for you.

 

[Tepot]

Performer & RPM heads are same ...EXCEPT ... the RPM has NO exhaust Xover ... NO Xover is a good thing for most.

For most folks: Performer cam is too small ... RPM cam too big.

Plain performer intake (not RPM) will work just fine with RPM heads and a good cam ... it'll work well with your Qjet too ... and it'll fit under the hood.

If your your '74 L48 still has its low compression dished OE pistons ... Suggest:
RPM heads (64cc)
Your current performer (2101) intake
Your (freshened & tweaked) OE Qjet carb
Your (freshened & tweaked) OE distributor
hydraulic flat tappet cam & lifter similar to these: SpeedPro/Sealed Power P/N KC-1013R or Summit P/N SUM-K1103 ... ~.443"I/.465"E valve lift ... 214*I/224*E duration @ 0.050".

With all the above: Static CR result will be about 8.8:1 to 9.1:1, make about 315HP/360TQ at flywheel, will have good vacuum & street manners, but will lope. G'Luck!
JACK:gap

Thanks for that detailed explanation Jack

I might consider your suggestion. 315 HP is tempting. But The cams that you are refering to, do they sound rough or smooth?

 

[WhiteKnight]

Tepot,

Here is a link to a engine builders site that has loads of live run videos and some in car videos including a '71 and a '69. They are big files so be warned, but they should give a reference as to what level of lope you are looking to achieve. Keep in mind that the race motors, while having very rough idle would not be good for the street due to poor vacuum and part throttle response.

 

[JohnZ]

Thanks for that detailed explanation Jack

I might consider your suggestion. 315 HP is tempting. But The cams that you are refering to, do they sound rough or smooth?

Are you going to listen to it idle all day, or are you going to drive it? Buying a cam based on its "lope" is a BAD idea. The cam needs to be matched to the other components it's going to work with, or the consequences are all negative. "Over-camming" is almost as prevalent as "over-carbing", both of which create lousy compromises. Engines are a "system", and each component should be selected to work in concert with all the others to achieve the desired result; it makes no sense at all to put a radical cam in an otherwise stock engine.

 

[Tepot]

Thanks for all your replies guys.

I've finnaly made the decision to stay with my engine that I got right now. It run's really good. So I'll keep it the way it is.

I was talking to a Friend of mine and when the time comes that my engine needs to be replaced. He'll will order me a crate engine with alot more HP. But for now. I'll leave it the way it is.

I just didn't know too much about engines and I had to ask the question, I tough changing the cam was not a big deal. but I guess it is.

 

[kenwa]

Good decision, Tepot.

I know what you mean though. I could listen to an L88 idle all day long...

When it comes time to beef up your engine, remember that horsepower starts with the heads. The rest of the engine is chosen to complement them.

Ken

 

[Jack]

Are you going to listen to it idle all day, or are you going to drive it? Buying a cam based on its "lope" is a BAD idea. The cam needs to be matched to the other components it's going to work with, or the consequences are all negative. "Over-camming" is almost as prevalent as "over-carbing", both of which create lousy compromises. Engines are a "system", and each component should be selected to work in concert with all the others to achieve the desired result; it makes no sense at all to put a radical cam in an otherwise stock engine.

I strongly agree w/ JohnZ on this ... 100%!

BTW ... suggested that cam profile, primarily, for its streetability with the 350 combo I described ... that rather common profile is a mild street-strip cam ... however, it will have some lope in same combo ... lope not pronounced, but noticeable. Of these 5 "idle quality" descriptors: "stock, smooth, good, fair and rough" ... it is "good".
JACK:gap

 

[lightingrod]

Over the years I have had Performer RPM cams in both small and big blocks and liked them in both flavors! There has been some good advice as well as some wise butt comments! I love to hear a big cam motor idle and rapp up but I too am into what it does. My choice for some years now for the street is hyd. roller cams! For a given performance level they will have a lot less lope than a flat tappet but then again they will have better vacuum and low end torque as well!

I think it's good you decided to wait because choosing a cam is one of the biggies when building an engine! The cam is like a mechanical computer that really sets the nature or personality of an engine! Also note that what might be considered a “BIG” cam is a 327 is just so-so in a 383. Do a little reading and keep asking questions, then make up your mind about what you want, cause it’s your car!

Al