# Camshafts



## Anthd7767 (Aug 8, 2020)

Hi all,

I was curious if anyone has used the Edelbrock 7157 performer rpm camshaft. I seems to have a nice broad rpm range, but I haven't found anything describing idle quality. My 389 has the Performer rpm intake and has had some work done to it, but I haven't been able to track down what exactly was done. The only thing I do know is it has some head work done, dual springs and comp roller tip rockers and a very mild cam from what I hear out the exhaust. The engine runs strong but has some valve train noise at start up and takes a while to quiet down. I have adjusted the valves, but I suspect someone used those variable duration lifters (junk IMHO) and that's where my noise stems from... I'm looking to upgrade over the winter months. The car is an original 3.90 safety track car with a 2 spd trans (weird combo). I don't mind the rpms on the highway just want to have the right cam installed to match the rear and will prob do a OD trans swap at some point......Thoughts

Thanks


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## GTO44 (Apr 11, 2016)

I have a customer with that cam in his Pontiac 400 (‘77 ta). I cant comment on performance as someone built his motor with less than 8:1 compression by using the wrong pistons... so with that cam it makes the car feel like a turd. But i will say ithe cam sounds good. Here’s 2 idle clips of it...


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## Anthd7767 (Aug 8, 2020)

Thanks for the reply.... Definitely sounds nice and is what I'm looking for, is that an automatic car or stick?


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## PontiacJim (Dec 29, 2012)

Anthd7767 said:


> Hi all,
> 
> I was curious if anyone has used the Edelbrock 7157 performer rpm camshaft. I seems to have a nice broad rpm range, but I haven't found anything describing idle quality. My 389 has the Performer rpm intake and has had some work done to it, but I haven't been able to track down what exactly was done. The only thing I do know is it has some head work done, dual springs and comp roller tip rockers and a very mild cam from what I hear out the exhaust. The engine runs strong but has some valve train noise at start up and takes a while to quiet down. I have adjusted the valves, but I suspect someone used those variable duration lifters (junk IMHO) and that's where my noise stems from... I'm looking to upgrade over the winter months. The car is an original 3.90 safety track car with a 2 spd trans (weird combo). I don't mind the rpms on the highway just want to have the right cam installed to match the rear and will prob do a OD trans swap at some point......Thoughts
> 
> Thanks


The cam specs appear to be the same as the factory Ram Air IV cam. Really not the best choice for a street car unless you drive hard. You might even have this cam in the engine and thus the variable lifters which are generally recommended with this cam on the street.

As pointed out by *GTO44*, knowing your compression can be important when selecting a cam or what is known as a high-performance cam can wind up not being so high-performance.


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## BearGFR (Aug 25, 2008)

Anthd7767 said:


> Hi all,
> 
> I was curious if anyone has used the Edelbrock 7157 performer rpm camshaft. ...


Howdy,
I looked up the specs on that cam and found: 
Duration @ .050 Intake: 231 degrees • Duration @ .050 Exhaust: 240 degrees • Lift @ Valve Intake: .470” • Lift @ Valve Exhaust: .470” • Lobe Separation: 113.5 Degrees • Intake Centerline: 112 Degrees 

It's a flat tappet cam so it's going to have more overlap than an equivalent roller would, but still it's not a whole lot more rowdy than stock. 

You're right about the transmission, that's probably hindering you more than anything. Having a lower first gear and/or perhaps a 'looser' converter would wake it up some. A possible issue with a loose converter would be that at highway speeds, it might still be "in stall" which would make the trans run hotter. For all around performance, it's hard to beat a good OD setup. You can get a lower first gear for better launch/low rpm performance without having to live with excessively high rpm at highway cruise. 

If you do change the cam, make sure that your springs are matched to it and have enough spring pressure both closed and open to keep the rest of the valve train under control. Having a lifter 'get thrown off' a cam lobe because the spring can't control it will destroy an engine in short order. Spring installed height and coil bind height are also important if you choose a cam with more lift. Also retainer clearance, both to the rocker and to the top of the valve guide at max lift. If you know your current spring installed height and also the max valve lift dimensions for a cam, you should be able to take a couple sets of your existing springs to a capable machine shop and have them measure the spring pressures at both dimensions. The cam vendor should be able to tell you what their cam needs in terms of spring pressures. That'll tell you if your current springs can be used with a new cam or not (provided they're also ok with both installed height and max lift height).

There's a lot more to a cam swap than just changing out the bump stick itself.

Bear


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## PontiacJim (Dec 29, 2012)

BearGFR - "It's a flat tappet cam so it's going to have more overlap than an equivalent roller would, but still it's not a whole lot more rowdy than stock."

PJ - 87 degrees of overlap is "rowdy." LOL It is the RAIV cam. 308/Int/320Ex advertised duration.


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## BearGFR (Aug 25, 2008)

PontiacJim said:


> BearGFR - "It's a flat tappet cam so it's going to have more overlap than an equivalent roller would, but still it's not a whole lot more rowdy than stock."
> 
> PJ - 87 degrees of overlap is "rowdy." LOL It is the RAIV cam. 308/Int/320Ex advertised duration.


No kidding? I didn't recognize it from the @ 0.050 duration numbers. I wonder which rockers he's running? I previously had a solid roller in mine that was 236/242 @ 0.050 on a 110 LSA and made .600 lift at the valves with 1.65's, and it wasn't all that nasty. Being a roller, it didn't have as much overlap - plus it was in a 461 so the extra inches tended to tame it down some. It made about 13-14" of vacuum at idle.


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## Anthd7767 (Aug 8, 2020)

Thanks guys... Not my first rodeo, but it is my first Pontiac so I appreciate all the Pontiac knowledge flowing my way thank you! The motor from what I see from external snooping has #77 heads so if I'm correct it has small chambers and from looking into the spark plug hole appears to have flat top pistons with four reliefs in it. I'm guessing it has about 10.5 to 1 CR. I'm not drag racing this car LOL, but I do love the aggressive street machine sound! I am kind of a fanatic about how the engine sounds from a mechanical point and from an enthusiasts perspective. A valve train that is not set up correctly and makes noise other than what was deemed acceptable from the factory is unacceptable to me and actually an embarrassment. So when I start her up I cannot have that valve tick that sticks around for a bit...that drives me INSANE. So if I'm going into the motor at some point I will be making a balanced decision based on my experience and input from helpful people such as yourselves....I love the fact that my wife wants to drive the car, but I would LOVE to put a third pedal int he car with a five speed...unfortunately not happening. Slushbox it will be. but like I stated early maybe add an extra two gears down the road....I think the tall rear gear will help and even if its a little sluggish down low until I make a trans change having it breath better at 3K and up on the highway will make me grin! And yes I do drive it hard.......LOL it's a muscle car....


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## BearGFR (Aug 25, 2008)

Anthd7767 said:


> Thanks guys... Not my first rodeo, but it is my first Pontiac


Since you mentioned it's your first Pontiac. Hopefully you're aware that the factory valve train with the 'bottleneck' rocker studs and stock rocker nuts is not adjustable? Those nuts get torqued down onto the shoulders of the bottlenecks at 25 lb.ft. Getting an adjustable system requires replacing the factory nuts with poly-locks. If someone attempts to adjust the factory system like a chevy, the nuts will loosen over time and things will get noisy.

Bear


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## GTO44 (Apr 11, 2016)

Anthd7767 said:


> Thanks for the reply.... Definitely sounds nice and is what I'm looking for, is that an automatic car or stick?


Its an automatic. The car drives great on the street. You can tell the cam comes on higher up in the rpm range. If it had more compression it would feel good. He also has edelbrock performer RPM heads and a performer dual plane intake in these videos.


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## Anthd7767 (Aug 8, 2020)

Cool... Did he wind up using his stock converter? Bear commented on it being a copy of the RA4 cam and the way I see it looking at the Comp cam and Crane Blueprinted specs, the LSA's and lift specs are different, but duration is the same. 509 for orig and 470 for Edelbrock.... 113.5 vs 111 or 112 or something (I don't have the books at work lol). I like the lower lift specs for the street prob a little easier on the springs for cruising... Edelbrock does not recommend a dual spring for the for that cam though which I thought a little odd.....Anyway thanks for all the feedback fella's, I'll update you after I pull the trigger.....


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## Anthd7767 (Aug 8, 2020)

BearGFR said:


> Since you mentioned it's your first Pontiac. Hopefully you're aware that the factory valve train with the 'bottleneck' rocker studs and stock rocker nuts is not adjustable? Those nuts get torqued down onto the shoulders of the bottlenecks at 25 lb.ft. Getting an adjustable system requires replacing the factory nuts with poly-locks. If someone attempts to adjust the factory system like a chevy, the nuts will loosen over time and things will get noisy.
> 
> Bear


Thanks Bear for that tidbit of information.... I didn't know that...but the engine does have poly locks and I use the zero lash method + 1/2 turn with the lifter on the base circle. Thanks


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## lust4speed (Jul 5, 2019)

Here is a partial list of a few others that have copies of the RAIV:


*Pontiac**9794041**308 *​*320 *​*231 *​*240 *​*.470 *​*.470 *​*114 *​Comp. Cams51-116-3308​320​231​240​.470​.470​114​Crower60919304​316​231​240​.470​.470​112​Edelbrock7157308​320​231​240​.470​.470​114​H-O Ent.041k308​320​231​240​.470​.470​115​Lunati10703308​320​231​240​.470​.470​113​


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## 1968gto421 (Mar 28, 2014)

For easy determination of overlap in a cam, the Wallace calculator is one of the most frequently used. Link below. Note that it uses advertised duration rather than the familiar .050" lift duration.





__





Camshaft Overlap Calculator - Wallace Racing


Calculate Camshaft Overlap From Lobe Centers and Duration



www.wallaceracing.com





Hope this is helpful (overlap frequently determines idle qaulty, i.e. more overlap = rowdier idle).


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## GTO44 (Apr 11, 2016)

Anthd7767 said:


> Cool... Did he wind up using his stock converter?


Its not stock, i believe it was a 2,200 or 2,400 stall. Nothing crazy


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