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i am looking into building a small block chevy with around 500 hp. i have the edelbrock performer rpm package ( heads, cam, and intake ) on my motor right now. i think its around 375-400 hp. i want to keep those parts on my new motor. they work great for the street and the strip. do you think that i can get 500 hp using the same cam, heads, and intake ? thanks for any help.
 

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A 100 to 125 hp shot of N20 should do it!

Or maybe a 420 +cid stroker kit would get you there.

Or maybe some professional head porting and a 383 stoker kit.

If your heads don't flow at least 250 cfm at the maximum lift of the cam then it will not make it to 500 hp
 

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rpm package

I have the same package and I'm trying to get as much as I can out of it. I haven't heard very many good things about the heads we have except from edlebrock. When I bought them I thought they would be the bomb. I'm wondering if we took our heads to a reputable machine shop if they could give them some more steroids. Good luck
Ron
 

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I think you've got the wrong approach. Don't build a motor to get a number. Numbers are arbitrary measurements of meaningless units anyway.

Here are the facts:

YOu have a heavy car, and you need cubes. If you want to go fast, you might consider another chassis altogether. If you want to keep the one you have, get a 383 or a 400. A 350 would be ok too, but you really want the low end response of a larger cube motor with a big boat like that.

Keep your heads. UP your cam because you can use more cam in a bigger motor. Use a 2500 stall and 373 gears. Don't worry about meaningless units.

You'll be happy with the setup.

K
 

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I dont know the size of your motor, but with those parts, it would be difficult to get 500 hp even if they were on a 406. With the car you have, I would look first into either stroking your motor to a 383 if it is not already one, or building a 406, in order to get more torque. If you did build one of the previously mentioned motors, you would have to get your heads ported, and get a bigger cam to get the performance you are looking for. One other idea is to sell the parts you have and start over with a set of AFR 195cc heads with a hyd roller on a 383, that can easily be a 500 hp, ~500 tq combo with the right cam.

Good luck
Adam
 

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everyone seems to be overlooking the potential of the Edelbrock RPM heads. If you have some time, look into some basic port work for these heads. They flow about 235 cfm stock, and with some bowl blending and a 5 angle valve job they should easily get to the 250 cfm mark. Remember, if you are after a specific horsepower goal, displacement only indicates how high you must spin the motor to get that horsepower level, more or less. You could do it with the 350, but you would have to rev pretty high and this would both require a big cam that would take away from streetability as well as risk breaking parts. I agree 100% with killerformula that building a bigger cube engine makes it so much easier to get high HP levels and keep it streetable. My suggestion is to keep the Edelbrock heads and manifold and use it on a 406 (unless you already have a 350 block, which would make a 383 cheaper), and just do a little porting to the heads. Just watch your compression, I believe Edelbrock heads come with 64cc chambers on some of them.

Porting heads is a little time consuming, but it is very easy even for beginners, and costs only peanuts in comparison to better heads. If you are interested, PM me and I will give you some pointers. I have a lot of experience porting heads with some great results (don't let my age fool you).
 

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firestone said:
One other idea is to sell the parts you have and start over with a set of AFR 195cc heads with a hyd roller on a 383, that can easily be a 500 hp, ~500 tq combo with the right cam.

Good luck
Adam
Sometimes I think Adam gets commission from AFR :D

But I agree with him on this issue, and maybe I am a little bias toward AFR as well. Before building my 383, I put a lot of thought into heads. I had a set of Performer RPM heads on a 355, but noticed that you never see any 450+HP (N/A) engines that use them (published articles). At least I haven't.

What I did notice is that American Speed Enterprises, who gets tremendous magazine exposure, uses the Edelbrock heads on 355 and 383 engines that they build to about a 450 HP limit (which includes some porting). Above that, they use AFR 195 heads almost exclusively. Check out their different dyno tested builds here.

You can also read a number of magazine articles at AFR here. Go to the articles and dyno tested combos sections. You can build a 500HP 355, but as Mad Maggot said, you will need a big cam (like 240+ @.050) and a lot of RPM. Here is one example. And IMO, it would also need over 10-1 and a head such as the AFR 195.

There is nothing wrong with the RPM heads. But, if Edelbrock were to build a 450+HP engine, I'll bet they would be the first to dump the RPM heads, and upgrade to something like their Victor Jr. heads, which are more comparible to the AFR line. Again, this is just my opinion.

Good luck making your choice. Ed www.edgesz28.com
 

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If it were me, I would do the larger cube thing everyone is advising. I know that the RPM heads are not a super high flow head, but I dont see why you could not make them work. As previously suggested, I would start with cleaning up the bowl and short turn radius and then gasket match to the intake. I would not get crazy since you dont what to ruin those heads which is not hard to do if you just get grinder happy. Next thing would be to toss the RPM intake for a Victor Jr. or an AirGap. You will also need a 240-250 duration range cam to get close to what you are wanting with the restricted heads.

If the heads dont end up making the power you are wanting, it is easy to swap them out later in a matter of a day or less.

Chris
 

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Another thing to consider, is buying a new set of pistons, and putting an intercooled procharger on it. With around 10-15 lbs of boost, you would reach 500 hp pretty easily.

Adam
 

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500hp

That number can be made with those heads but you will need port work done. Also a larger cam and swap intakes as previously stated. Your intake can probably be salvagable but would also need to be reworked. I am currently running these heads in a stroked small block with a port matched air-gap intake and just a shade bigger cam and although I didn't reach the 500hp mark all dyno runs were above 485hp. But as killerformula stated with the heavy car you are better off with 425-450hp and build for a larger torque number.
 
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