Thread: Final couple questions for build.

Tweet

Sorry for all of the questions guys but I just have a few more. First would stock 351w heads due the trick for my 347 or should I put out the money for some aftermarket ones? Second for a street/strip application would idle to 5500RPM or 1500-6500 RPM be a better option. Been looking at cam/intake combos and trying to figure out which would do me better in the long run, I am in no hurry to build this motor so I want to do right. And if I do need to buy Aftermarket heads what would be a good choice for a ford, I have heard AFR are good but unsure.

Thanks to All

Originally Posted by mustangkid

Sorry for all of the questions guys but I just have a few more. First would stock 351w heads due the trick for my 347 or should I put out the money for some aftermarket ones? Second for a street/strip application would idle to 5500RPM or 1500-6500 RPM be a better option. Been looking at cam/intake combos and trying to figure out which would do me better in the long run, I am in no hurry to build this motor so I want to do right. And if I do need to buy Aftermarket heads what would be a good choice for a ford, I have heard AFR are good but unsure.

Thanks to All

I've been there, done that with stock production heads until I want to hurl. With the choices that are available from the aftermarket today, it just makes no sense anymore to fart around with archaic designs. AFR, Dart, Edelbrock, Trick Flow, Brodix, Canfield, Holley, RHS and I'm sure others that I'm not considering at the moment, all make fine cylinder heads that will work far better than OEM production heads.

I don't have multi-million dollar facilities or the ability to test every combination that comes down the pike, but what I have found with running combinations on my DynoSim as well as talking to other amateur builders and racers at the drag strip is that the best choice for a street/strip motor using a hydraulic cam (solid or roller) is the Edelbrock RPM or the Weiand Stealth because the valve train is all done at just over 6000. Now, if your build includes a solid cam and you're building for power 5000-8500 or better, for instance in a dedicated drag race motor with a 5000 stall converter or a circle track car that comes off the corner at 5000, then yeah, a single plane intake would be the logical choice. The swap-over comes right at 6000. Up to 6000, the high-rise dual-plane will make more power under curve. Over 6000, the single plane will make more power under curve all the way to redline. If you're building a daily driver with a short cam and stock converter, you might consider the standard Edelbrock Performer. It's little more than a low-rise OEM manifold cast in aluminum, but as least it will get some weight off the front end of the car.

When building any kind of performance motor, if you're using an automatic, you're going to use a looser converter than the stock one to get the motor up on the cam and past the mushy range. You won't lose anything idle to 1500 because you'll be stalling past that anyway. In a 3-pedal car, you definitely won't be concerned with idle to 1500 if you have any kind of performance gear in the third member.

I just went through exactly the decision making process you are going through. I decided to slow down a bit and spend a couple more dollars to do it a little better than my original plan.

As for the 5500 vs 6500 redline thing, I was faced with the same dilemma. The first heads I bought were E Streets that would have somewhat worked with my roller cam, but would top out at 5500. One of our Techs at work said "as long as you are spending that kind of money why limit yourself to only 5500......what if you miss a shift?" So I sent them back and got Performer RPM's that will go to 6500.

On the other side of the scale, I know AFR heads or TrickFlows would have given a little more hp, but for the street driving I am going to do 99.9% of the time I didn't need that top end power, would rather have it at the low to mid range. That is the decision you need to make, how you intend on driving the car. As long as you are going the 347 route good breathing will only make the engine run better. The 351 heads were the hot setup at one time, but technology has made better choices available.

You ask about AFR heads, and when I was researching my intended purchase AFR came up all the time as being about as good as they come. Everyone seemed to have respect for them.

Don

Hard to beat the quality of the AFR heads, but the Edelbrocks are a very good street head, too.... If I recall, you're running an automatic, so I'd say go dual plane intake and get all the bottom end power you can. For a street car, 5500 rpm is usually plenty, probably more revs then you'll ever use.....