Gone Johnson

Hi, my Olds 350 has a Edelbrock Performer 2711 on it. The RPM gains are in the off idle - 5500 rpm range. I like it, and it has pretty good throttle response.
In the interest of something better, I have been eye-balling the Edelbrock Performer RPM. It seems more robust, with a RPM range between 1500 - 6500.
My concerns are:
- Will the RPM range of the Performer RPM hurt off-idle performance (my 350 is pretty close to stock), or will it improve (because when I floor it, I'm pretty much at or above 1500 rpm anyway)
- Will the Performer RPM improve my performance when I'm racing (performance with the Edelbrock Performer falls flat at higher rpm, which is why I'm looking for more)
Online reviews aren't helpful, and there's not much here on this site.


Anybody got something for me?

olds 307 and 403

Some have claimed track gains with the 307 HO. I know one former member did track testing with the Performer vs the RPM on a 9 to 1 350 with a 210/216 cam, it slowed down with the RPM. The RPM is dual plane with long runners and is 2" taller. Many also notch the divider, Dyno and probably a gains at the track as well. What all is done to your 350?

Gone Johnson

Nothing much, it's completely rebuilt, a little polishing work, and a rv cam I think.
I get the feeling the RPM isnt for my ride. I mostly drive the hell out of it nowadays. I get into it with the ricers around these parts, & the last few times the engine seemed done making power too soon. I realize its a almost stock 350, but Im thinking theres more power in the intake. Also, Im planning on switching to EFI, because Im done with this carb (quadrajet 650) and its dang issues.

midnightleadfoot

Air speed is king, the rpm everything is bigger so the air flow is slower, and even though you hammer it and are over that 1500rpm the air speed is slower at 2-3-4k and most likely equal at 5k and then might start to be better over that.. cylinder filling requires time and air speed, a stockish cam limits the time and the bigger intake slows the air, less filling = less power..
I'd mill down the divider 1/2 the way down the intake on it.. That has been shown to help some ..

olds 307 and 403

The RPM only has slightly bigger runners but are much longer and that means good torque production. A 1" open spacer is an option on your 2711 Performer, increases plenum volume and allows side to side feeding, I just had one on my Performer and low end was good and pulled nice to my 5000 RPM shift points. I did switch to the RPM intake and 1.72 roller rockers this winter. What pistons were used in the rebuild?

midnightleadfoot

But a stockish cam = low lift and valve open short time, larger runners and the larger plenum (2") taller make the air lazier.. at low and mid rpm.. it is why it will go to 6500rpm+ and the performer won't without falling flat on it's face 99% of the time
He said he was going efi and I'd cut down the divider some as the tbi systems don't like self tuning with readings from only one side of the intake tract. Heck even in testing it gains power.. and tuning them manually with your screen only having data from 1/2 the intake tract, doesn't work all that well either..

Fun71

Why do you think it's the intake causing the power to fall off instead of the camshaft?

FYI, back in the 80s my engine with a complete factory rebuild, but a better camshaft, would pull to 5800 RPM. That was with the factory iron intake, points distributor, QJet, etc.

midnightleadfoot

Most do, because they see the rpm range listing as fact instead of a guide..
well this one is listed idle to 5500, but that one goes to 6500.
And an intake is easier than a cam swap..lol
I fell for that thinking when I was younger..
Brodix trackI heads, oh and not big enough, ported them, and a big single plane intake, with a 10.5 to 1 355 and a 292 cam, what a dog until you got to 3500 rpm then it was like hitting a light switch..and hold on..as 7000rpm came fast.. fun yes, but on the street, most times, na.. but sounded cool.. lol


That mistake needed to be in a car at least 1500 lb lighter than it was, and it would've been the e ticket.. live and learn..

Fun71

I just remembered that the W-31 intake manifold is essentially an aluminum version of the iron intake and folks report those engines would pull to 6000+ RPM with ease. This really makes me think the intake manifold is not the limiting factor for the OP.

midnightleadfoot

I'd love to see the dyno chart to see what the hp peak is and how much it drops off from peak when it got to 6000 rpm.+
Yes I know this isn't just an intake thing.. but it be cool to see same engine with iron/w-31/ performer and then an rpm..
I'm sure the cam and smog compression is more of an issue than the intake also..
but no one goes wow over the iron intake..lol.
Most of the aftermarket parts sold because of the owner of car wanting to impress people they don't know.. lol

70sgeek

I'm running the 2711 on my mildly modified '72 350 - flat top pistons, Howards Street Performer cam, HEI ignition with 9.5:1 CR - motor pulls pretty strongly all the way up as far as I've ever wound it - in the 4k range at most, and that's with 3.08 rear gears.


I'm wondering if your real limiting issues are the cam (since you don't know what it is) or possibly the carb (650 is admittedly small for SBO's from everything I've read - 750-800cfm Qjets being the norm).


In my case I feel like I've left some low end power still on the table by running an essentially stock 750 Qjet so I'll soon be swapping it for one which was performance-calibrated to my motor by Ken at Everyday Performance.


Even so, my current Qjet performs flawlessly (albeit in its relatively pedestrian state of tune) - clean acceleration, mild idle and quick starting (when not having sat for a few days...). So possibly your Qjet needs upgrading at the very least?

oldcutlass

#1 issue is that your stock engine was never intended nor designed to run above around 5400 without floating the valves. Each time you exceed the rpm limit and float the valves, you will weaken the springs to the point in which future performance starts to drop. Stick with your current setup until you can afford to do it right with matched parts that work together.

Gone Johnson

I have to admit something, you guys, I cannot have a conversation about camshafts, lifters, or rockers. I aint knowledgeable enough -lol
I have fixed, replaced, or both, just about every component on this car. But the engine (in 1998), I had rebuilt with a kit that included a RV camshaft, no pistons, just rings, bearings, oil pump, timing chain, gaskets. Im guessing close to stock stuff. And I can't tell you anything about the heads, I brought in my old ones and had the guy do his magic. I do remember The Machinist telling me I will be able to use unleaded gas with no problems now. Also he up sold me on some porting/ polishing work. Then I put the engine in (in 2000) and only recently started beating on it, ( still has under 10k miles) when I noticed that it falls on its face, at the end of the quarter mile. I bought the Edelbrock Quadrajet Carburetor (650cfm), and the 3711 (I have a 2711 Performer I want to switch to, because of the non EGR boss, so I can actually have a linkage that doesn't hit), & the Performer manifold, that the auto parts store guy recommended, but I did not know what I was buying. I came from having a 2 barrel with the cast iron manifold, so anything was better.
The carburetor has had so many issues that I just want to dump it. And start over. Hence the fuel injection. Maybe I should have also mentioned that I still am running the stock exhaust.manifolds.... maybe this is the reason engine falls flat. I do have dual exhaust....

olds 307 and 403

I assume your car is a 71 or 72 and it is a stock 350? Assuming a clean up mill on the heads and the stock 24cc pistons, you have low compression, less than 8 to 1 with Felpro gaskets. I would guess your cam is the 204/214 variety, which also bleeds cylinder pressure. I would advance the timing as much as possible. Stick with the Performer, Mark's new Mahle 10cc hone to fit pistons are what you need.

Gone Johnson

So.... either enjoy it the way it is, or rebuild the engine with better pistons, cam, valves, springs, and rockers, is what Im hearing?
Sounds like I should just buy somebody's built 350 when they yank it out of their car, have ot gone through, and install that one day.
I guess for now I'll finish my upgrading. I like that talk about notching the plenum on the manifold, I know the EFI will be awesome, and I guess I'll work on some sort of header. That is a whole new topic, we don't have to talk about here. it doesn't seem like any of them fit without sledge-hammering them. haha

olds 307 and 403

Sanderson shorties fit with a mile of room. The only tight spot on my 70S was the steering shaft but cleared fine.

Fun71

This is what I was thinking as well. You have a dependable daily driver engine that, as your mechanic said, will run on regular gas. You DO NOT have a performance engine, which is why it "falls on its face at the end of the quarter mile".

Do you know what RPM the engine is turning at that point? It could be the cam is beyond its power band, the valve springs could be weak and starting to float, or if it has a points distributor, the points could be bouncing.

olds 307 and 403

What time did it run in the 1/4 mile?

76olds

I have an internal stock 1976 350 :
I tried both the performer and the RPM on my 350 before I had it refreshed. I noticed the RPM manifold didn't have as much torque or ooomp from a dead start. Over 60MPH seemed better pulling out to pass, but I never drive it at that speed much.
The regular performer just seemed to have better low end torque and oooph, it seemed the same maybe a slight loss of pickup at 60MPH if I pulled out to pass.
That's just my experience with the two.
I'm currently running the regular performer with a 1" 4 hole spacer under my carb and headers which runs really well.
Hope this helps,
Eric

Gone Johnson

High 15's and a 16 something
( but on the second one at least I beat the Subaru hahaha)

Gone Johnson

Yeah I know I don't have a Performance Engine, I just thought it was abnormal. I'm starting to get the idea that it is not. I don't have a tach either. I put in an HEI and it improved things, but I'm going to leave it the way it is, with the exception of the other modifications I mentioned. like that I can drive it hundreds of miles at 90 with no problems, which brings up a funny point, I must have really high gears, because when I'm going high speeds, it doesn't fall flat on its face, only when I'm hammering it

Gone Johnson

Maybe I'm asking way way way too much here. It seems my ride has great torque, I can do a burnout forever. I can go 90 all day long, but when I need that EXTRA UMPH during the mid- or at the end of the quarter mile, that's when I'm experiencing the lapse of power.

76olds

Hmmm, something doesn't sound just rite . Funny point back at ya'. How long are your legs? Can you plant the right foot to the floor while still in the seated position ?
Just thought I throw it at ya'

Gone Johnson

lol... I've been having problems with this Edelbrock carburetor that I still have. It's long been a source of contention with me. Going with the EFI, for lots of reasons. It's still going to be my daily driver of course. But I feel until I get that thing replaced with something great, I don't have anything viable to tell you all because I lack the technical experience you do. I can tell you I've owned this car since 1990 and it never fell flat on its face before, even with a 2 Barrel.... how crazy is that?

Fun71

Well here's a thought - maybe at wide open throttle your engine is falling flat because it's running out of fuel. Perhaps the float is set too low, the fuel pump can't supply enough fuel, there is a restriction in the fuel line, or??

Gone Johnson

Yes... to be continued I suppose. I'm trying to get this thing installed by mid-march. I've already replaced or rebuilt the entire fuel system except for the EFI. So, I guess I will find out then if it changed anything when I hammer down above 60ish

olds 307 and 403

Not bad, I ran equal to mid 15's with a 8 to 1 350 with 204/214 cam, stock converter with a 2004R and 3.42 open gears with slicks. The 3.42 gears added .6 in the 1/8 mile over 2.56 gears.

midnightleadfoot

Timing curve /advance weights might be sticking or not working.. the vac advance dead..

or just the advance curve wrong for your engine.. a day playing with the mechanical advance (spring and weight kit) and an adjustable vac advance will be time well spent..
your problem if HERE!!!!!!!


You said you swapped to HEI what that come out of??? my bet is the timing curve is way off if it is even working correctly..

olds 307 and 403

What timing are you running? I found the same thing, great launch but went flat, starved for fuel, ignition misfire at mid way or the end of the 1/8. My 9.6 to 1 350 with same cam but double springs with just 1.72 roller rockers and a custom tuned Qjet ran nearly a second faster, gained at the mid and end of the track to make up the .5 in the 1/8.

Gone Johnson

The HEI came off of an Olds engine that was in a Chevy Blazer (yes, its true). I believe that engine was a '77 Olds.....
I don't remember where the timing is at, but I know I used my Chilton,s to do it.... so probably some factory spec

Gone Johnson

[QUOTE=olds 307 and 403;1073980] I found the same thing, great launch but went flat, starved for fuel, ignition misfire at mid way


I had this too, but thought it was a bad accelerator pump as the culprit. I'd operate the linkage, and no spray... thought it was a no brainer, but I still pop and sputter and starve on occasion. Smells so bad I gotta hang out the window for a while. This is the reason I want to junk the carb...
I know this is off the original posting, but maybe its all related?
I thought:
clean/rebuild fuel tank
Replace all 3/8" & 5/16" fuel lines & vapor lines
Replace mechanical fuel pump
Change to EFI
And, change intake to Performer 2711 or RPM..... I'm on the last step to my plan. it all needed to be done anyway.
Now I'm worried about the ignition.....

midnightleadfoot

If you can not troubleshoot a carb and mechanical timing advance you might think twice about that efi.. I know it states self tuning, but if you can't trouble shoot what you got now, electric sensors and such you will be lost..

Gone Johnson

I appreciate the advice. But, there's only one way to learn, and a little guidance along the way from those who have got lots of experience, never hurt anybody!

midnightleadfoot

True, but I'd learn on the carb and mechanical you got now, before diving into the efi.. That is all I'm say'n.. get the carb and timing working correctly.. learn from that, THEN move to efi..
That is all.
Way too many think , well I can't get this junk carb to run right, I'll just get the bolt on self learning efi.. and then have the same problems . only now it's problems are compounded

olds 307 and 403

Which EFI are you planning on? I would seriously consider a new EFI fuel tank and in tank pump to go with it. I say a 1" open spacer is a good idea on the Performer, absolutely no low end torque loss, mine fried the tires with ease. Unfortunately I didn't get to test the combo at the track, my Daughter toasted my 2004R trans the day before. I have since switched to the RPM which I did notch and use a thick gasket. I would use a 1" spacer on it but my homemade dual snorkel air cleaner, made from two air cleaners would probably hit the hood.

Gone Johnson

I have a feeling your engine is not quite the "stocker" that I have and I'm trying to pep up.... so does this mean when my daughter gets her license, she can drive my car? Haha
Im going for FiTechs Go EFI, and going to use the sump (Fuel Command Center). I installed one already in my neighbor's 72 Duster. Pretty simple job. He loves it, and noticed better fuel economy, power, and less "old car fuel smell" right off the bat.
The sump has received mixed reviews, but Im confident those kinks have neen worked out. Since I already renovated the fuel tank, Ill just have to take a chance it will be fine. I did install the sending unit that has the 1/4" return, just in case I'll ever need an external pump. I'll definitely notch my manifold, and since I'm switching to the 2711, I can actually fit a 1 inch spacer now