Which carb and intake for my 428?

Hi!

Which carb and intake manifold would you recommend for my application?
It's a 435cui, RAIV cam, E-Heads, headers, msd ignition, 4 speed manual...
I want the engine to run strong up to 5800rpm and not lose much if any low end torque.

For intake manifolds the choice will be Edelbrock's Performer, Performer RPM or TorqerII.
Carbs I already found and think they might work are the Edelbrock AVS 800cfm or the Holley Ultra Street Avenger 770cfm. The calculation program said 770cfm is enough, but I think it might be a little bit too small.
I also need a carb that can handle the "big" cam by giving me good adjustment features. If some carbs are better for bigger cams I'd prefer one of them. I also want a electric choke! Maybe you can give me some information what would work best for my car.

Chris  

If you don't want to lose low end torque but still stay strong up to 5800, I'd say a Performer RPM.

as far as tunability goes on the carb. I like the Street Avenger. Was gonna put one on my build. I like the quick change spring kit on the secondaries and the dual metering blocks.  
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Do you know if the Performer RPM with the Holley carb and 14x3" filter will fit under the hood of my 66 GTO?  

Hello  

An intake is frequently determined by mechanical variables such as compression head flow camshaft engine size etc. not always on driving style alone. Because I don’t know all your particular specs it is impossible for me personally, to offer you an informed suggestion at this time. I can however suggest you read the recent post by ta455 titled "double pumper for a 455". He also had a similar carb question which I and others posted info on. There is a lot of info there already regarding carb selection that might help you in your decision. There are also many other topics on carbs and intakes on the site. It if you use the search feature you will find some.

At this point I can only offer examples, hopefully this may help you to some degree. I have read read that the std performer flows similar to a stock iron manifold. If in fact this is the case then the main benefit to a performer in this case is weight savings and also appearance if you like the look.

INTAKE - If you run a stock or mild cam and you have tall gears ie. 2.80-3.00 the performer is probably the best option. If you have an hp cam like an 041 or similar or larger, I would suggest the rpm and the use of shorter gears like 343 to 373.

You will loose a little bottom end performance and throttle by using an rpm over
a std perf, that's why the call it an RPM manifold however this loss of bottom should not be extreme and can be compensated for by increasing gear ratio if desired.

As mentioned I personally believe the intake should be matched to all the other components and vise versa, and driving style needs to adapt to the set up. The set up does not adapt to the driving style once it is set. One should purpose build everything in advance for the driving style/performance level desired.

INTAKE FIT – I have an rpm style intake manifold [but not the new eddy style] on my 66 389 with a 3" tall edelbrock triangle aftermarket air cleaner and holley carb with no hood interference issues.
   
CARBURETOR – I personally would never intentionally install any carb other than a holley square bore style if possible. The other “jet needle” style carb’s provide better mileage than a non “jet  needle” type like a holey square bore and are xlnt carb’s once properly tuned. A holley is far easier to tune than the other style especially for novices. I also would never use a vacuum secondary type carb on any mild to hi perf motor. If for whatever reason you decide to run a vs type carb on a high perf build like a motor with a cam similar to an 041 or larger, but you still want the best low end  throttle response a carb can give you then I would suggest an annular boost venturi type carb, like a mighty demon or quick fuel etc. Summit racing only lists 1 or 2 avengers  as an annular booster type for some reason, but perhaps they  all are, call holley if more info is needed. They are both 770 cfm annular vs types one with electric choke the other with manual choke.

Hope this info helps  

Hi! This information helps a lot, thank you!
I have about 10.5 CR and the 041 cam.. For me it has now enough low end power and at about 1800 it starts to run very strong. I don't need the high rpm's often,that's why I'm thinking of the Performer instead of the RPM intake.. if the Performer gives good power up to 5500 and don't loose much from 5500 to 6000 compared to the RPM I think I won't need the RPM.

I read that it's possible to use a spacer on the Performer and have good low end and also more power above 5500rpm. Maybe this could be what I need? If hood clearence is not enough I could easily remove the spacer.

Is 770cfm big enough for my engine?  

Hello

I personally would use the performer rpm but mainly because I would be driving that car harder than it sounds like you would plus the perf rpm is better matched to the 041 cam you have and since you have sufficient compression your motor would be ok with it. If in fact the std perf is similar to a stocker in flow than that would be another reason for me to go with the perf rpm since if I am correct that cam came in a car with a high perf aluminum manifold from the factory.

I personally wouldn't install a cam like that then restrict it's full potential by not using a less restrictive manifold etc.

The good thing is that if you do install the std perf and want more than it's not that expensive to buy the rpm, sell the std and change it yourself!

CARB - I personally think the 770 is going to work better for you since you will use the std perf and not rev it over 5k often. You don't need the extra flow at lower rpm's. It's extremely easy and very common to install a carburetor that is larger than needed than the intended use calls for. Bigger is not always better

Hope this helps.  

I agree with that.. maybe someone has the Perf RPM in his 66 GTO and can tell me how it fits.. your's is about the same size I guess?! And it fits.. probalby it would clear my hood.

At the moment I have a tri-power manifold.. what is the rpm range of the tri-power?  

Hello

Yes mine is definitely as tall as a performer rpm and yes it fits easily in my 66 GTO. It has been on there a while. My motor turns high rpm with plenty of bottom through low gears, xlnt throttle response, and as fast as I want to go.  

Hello


I just checked out this exact same thing over the last few days and below is what I found.

This is a bit of a guess but from what I have seen 65 gto had a 472 cam and howards cams makes an exact replica of that cam and rates rpm range on a 65 389 tri power at 1700-5800.  

Hello

My gears are probably 373 with an auto but it easily has enough bottom end to run hard with 350's or 343's and this is with a 389 not a 435 like yours.  

Perhaps Rowsley will see this and offer his comments, I think he has a similar set up with the 041 cam and eddy rpm in a 455. He's very knowledgeable.  

Hello

Just did a dyno sym for using comp cams dyno and the old 280h comp cam unfortunately comp doesn’t list intake manifold flow by mfg.

This is what they list for dual plane's, low, high, and max flow. I’m guessing the std eddy is between the low and high comp manifolds and the rpm is easily above the high comp.


RESULTS

Low flow   376 hp  4500,  472 tq 3500

High flow   405 hp  5000,  494 tq 2500

Max flow   437 hp  5000,  504 tq 4000


Old 280h comp cam used for test    280   288  232   237  intake closes 66 abdc

Hope this helps.  

hello

just looked at summit there is only one manifold they list for 428 which is the std performer. have you seen the other ones?. says 1000-5500 rpm  

edelbrock.com does not list 428 either. do you know for sure the intake is the same as 350 thru 455?  

Yes the Performer RPM will fit the 428 too.
Steve  
A little help... 'cause we don't all have to learn the hard way!

All edelbrock manifolds that fit to the 400 or 455 will fit on my 428.. I can choose between std performer, rpm, torqerII...
Maybe the performer rpm would be a good choice and if it fits under my hood I don't see any problems. The Holley carb I found has 770cfm.. should I search for another one with more cfm?  

CHris,
that 770 should be good up to about 5200 RPM based on CFM requirements alone without taking into account the camshaft/head flow characteristics. If you want to push it up to 5500 RPM or more, than I'd go with an 800 or 850 CFM.  
Jim,