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Aluminum Heads vs. E7 Powerheads, What would I gain?

6.1K views 41 replies 17 participants last post by  99FiveOh  
#1 ·
I am currently running the following:

302
E7 Powerheads - CNC Ported
Crane 1.6 RR
Camshaft Innovations Custom Cam 520/520 lift
TMoss Ported Upper/Lower Stock Intake
70mm MAF
19's
AOD / Lentech Street Terminator / Edge 3200 Stall
4.10's

I am thinking of going with a small 5-6 psi supercharger (Powerdyne or Novi 1000) or with a set of aluminum heads and intake package. I can only do one or the other and was leaning towards the heads.

I have researched the flow numbers on the Powerheads and some of the popular Aluminum Heads and it seems that the Powerheads flow fairly well which is making me consider the SC instead now.

Here are some numbers I have found. So what will I gain by going to aluminum heads other than the weight savings?

POWERHEADS:
100 64 63
200 123 110
300 175 151
400 204 170
500 217 175
600 N/R

TRICKFLOW STREETHEAT
100 72 48
200 138 78
300 181 100
400 207 125
500 220 135
600 230 140

AFR 165
100 N/R
200 123 118
300 186 153
400 225 178
500 250 185
600 250 191

AFR 185
100 N/R
200 129 118
300 189 153
400 224 178
500 267 185
600 282 191

FRPP GT40X
100 65 52
200 126 105
300 172 145
400 202 149
500 216 149
600 215 149

The AFR 185's make a pretty good jump in the 400 - 500 lift range, but if the cam has 520 lift and through the valve event, spends more time between 300 - 400 lift than at max lift, will it really be worth it?

Not pretending to know anything here, legitimately looking for answers and help understanding.

Thanks.
 
#2 ·
if Jay designed the cam specifically for your application then that cam will be completely wrong for larger heads and blower, many variables come into play when lookimg at heads, such as port volume, valve size and spacing, chamber layout, plug location, cross section etc.....
 
#3 ·
When I talked to Jay (actually have an email in to him right now) during the design, I asked him to factor in a small SC or 125 shot of N20.

I recently discussed a spring upgrade with him as I seem to be running out of power at about 5200 rpm at which time he suggested a head upgrade to me, we didnt get into the head selection at the time though.
 
#6 ·
Out of your cost to gain ratio with your limitations on budget, the blower is your better bet. But your going to run into a limitation with how hard you can push the air through the pin-hole eventually, causing you to add cost of intercooler/aftercooler and or an eventual head swap....

But for now, the blower would bang for the buck win hands down over an "aluminum" head swap. To maximise a head change, would require, heads, intake, cam and possibly exhaust.
 
#8 ·
After having run power heads with a Perfomer intake and seeing the change I got on my engine when i went to 185s and a systemax, I would go with the blower. I saw my friends car (ericbluecoupe) pick up 14mph on the stock pulley setup with a Novi 1000. He was running 103mph with GT40 heads and intake. He ran the Novi with a power pipe and BTM and ran 117 and some change. I was amazed to say the least. We dont know the boost level it was at but he wasnt using the renegade pulley yet.

Oh and upgrade the springs on your heads, I had a problem with mine and they measure 205lbs at .500". That is not good at all. This caused enough valve float that the keepers on the valves had eaten into the valve stems. So the tops of the valves had to be file to remove them without damaging the guides.

Here are two links to how my car responded with the swich from the Powerheads to AFR 185s. Just remember that I went down from 1.7 rockers to 1.6 rockers. Dave.

http://www.corral.net/forums/showthread.php?t=618710&highlight=Dyno
http://www.corral.net/forums/showthread.php?t=767124&highlight=Dyno
 
#9 ·
Thank you for all the replies. I am looking to extend my RPM a little more, but it sounds like I might be able to do that with new valve springs.

It sounds like the SC is going to give me more all around power as opposed to a little more at the top.

I don't know why, but I am a little surprised. I really expected to hear more replies in favor of the heads. Personally, I wanted the SC, but just thought the heads might give me more.

I was using the rule of 10hp per lb of boost and if I was only running 6lb of boost that would be 60 hp at the top of the RPM scale. I thought maybe the heads would do more but guess not.

Slowhatch, thanks for the real life comparrison, the heads intake you chose was close to what I was thinking of changing to.
 
#11 ·
Its seems to be becoming the topic. :D

Like I said in my last post, for some reason, I was really expecting more replies in favor of the heads and as such was wondering with the above given flow numbers, how much I could really expect as there didn't seem to be that much of a difference on most until the 400-600 lift area.

My cam doesn't have that much lift so it wouldn't really spend much time in those lift areas so I was wondering when evaluating heads if what other factors if any I should take into consideration other than flow numbers. If that makes sense.
 
#13 ·
Keep in mind that when it comes to lift, your cam will spend majority of it's time at lower to mid lift and that max lift is not the only thing to consider, with a supercharger your valve timing needs will vary greatly from what's needed for optimum n/a performance. Majority of my experience is with N/a applications if you were keeping things N/a then I'd say you want the head with conservative cross sections and good mid lift flow. Out of the heads you have listed above and if we are talking about leaving the head in out of the box form, I'd go AFR 185 if you have the piston to valve clearance or don't mind notching the pistons, if that's a concern my 2nd choice would be the AFR 165. Now if we are porting the head, put the TFS Street Head at the top of list. Any of those heads can make good power, but it will always be about the combination of parts.
 
#15 ·
Well, I think its going to be boost. Will probably run with my current set up to see how it goes, then maybe change intakes to the Typhoon as I have read its a pretty good intake for SC.

This will start a whole new debate, but its between Powerdyne, Novi 1000, and the Vortech SC. The Powerdyne and Novi are both 1700.00 the Vortech is 1900.00 anyone know why the Vortech is 200.00 more when it advertises the same boost levels and components?
 
#16 ·
I like the paxtons and vortechs, just me but I'd pass on the powerdynes not positive experiences with those...
 
#17 ·
My friends Novi was very nice and worked well. He has taken it off his car for the time being and says he wants to sell it. You may want to PM him, his screen name is EricBlueCoupe. I bet he doesnt have more then 2000 miles on it and he has the renegade pulley, power pipe, btm, 42lb inj, and 80mm meter to go with it. Good luck with whatever you choose, Dave.
 
#21 · (Edited)
That opens up a whole new question for me. If flow bench numbers of heads and intakes have little bearing on real life performance. If duration at .050 of a cam is only a small portion of the performance aspects of a camshaft, how is your *average* gear head supposed to make informed decisions?

I mean I'm sure most know that you shouldn't run AFR 205 with an otherwise stock cam and intake, or that you shouldn't run a cam that's 280/280 @ .050 with 700 lift and 104 LSA with stock heads and intake, or a TFS R intake with stock stuff ect....

But if your putting together a combo and you use advertised flow numbers that are similar, to assemble it, am I to understand that you could still end up with a poor performing set up? All other supporting drivetrain items factored in (gears, converter, ect...)

Right or wrong, I think that realistically, flow numbers and durations numbers are how a lot of people make decisions on parts to run. So, short of running a combo that is designed to compliment one another like the Trickflow top end kit or the Edelbrock stuff what is the best way to sort though the vast number of performance items and come up with a package that will perform like the owner envisions?

Ready to take my understanding to a higher level.
 
#19 ·
get rid of those E7's they are very garbage heads, they flow like crap and it's a waste of money to port them just because you can get a decent set of GT-40's for like $300. I used to have E7's and when i did Edelbrock performer RPM's the car got wayyyyy faster.
 
#20 ·
Hmmmmm, and where did you get the information that Power Heads were "garbage". cleanLX used a set that flowed 229/182cfm and made 292RWHP/325RWTQ with a ported stock intake and a custom cam. He did have issues with spring heights that needed correction, but they still performed.
 
#23 ·
Actually your thinking is backwards............ if you want the power.

If the head is small, typically you require a longer duration lobe to facilitate filling the chamber, and or allowing the RPM window to make the power. At some point it becomes a futile effort... ie the head just cant flow any more no matter what (360 degree lobe duration)

The larger the head and the more efficient that it is, the less cam the engine requires because the air is already there.

Part of the problem with racing flow benches is none of them are calibrated exactly the same....... so one set of numbers from 1 bench seldom get close to the numbers attained from the same part on another flow bench.

LAstly flow bench numbers alone don't tell you anything about the head unless your the porter/flow bench operator. You can have head A, that has a cross section of x and a runner length of y, and it will flow 300 peak cfm, with a nice curve.

Now you can have another head that has a lower cross section, but also a shorter runner length, (ie, twisted wedges) and it will still flow 300 cfm.

Now to add a monkey in the mix here too, the two heads on the same engine would make about the same peak HP, but the longer runner would have broader torque curve (we are only talking about a 1/4 to 1/2" in this case so it would only be a small percernt variance) so someone with a more street oriented ride would prefure the longer runner head......


Back to the flow bench operator, by using dye, and listening to the port, its an invaluable tool for improving/maximising port flow for a given design, and once you have a base flow established, again invaluable for documenting improvements......
 
#24 ·
I'd say with those Powerheads and the custom cam, you have a great foundation to slap the charger onto. You know you're already making "more than stock" power, so with the supercharger you should make well in excess of what you would if you had a completely stock engine and a supercharger.

How close does your ported intake come to that of an aftermarket unit, like Edelbrock?
 
#25 ·
BocSez

Let me help you understand what Jay is saying

Head guys flow heads at 28"h2o because thats where the transition from the bench to the actual engine happens. In other words if we develop a port at, say 3" h2o where the engine really sees it, and it looks good on the bench but it won't do diddley on the dyno. But when we use the 28" h2o # and we develop that port and it looks good on the bench that shows up on the dyno as well.

There's more to what the head does than just the flow numbers, it has to contain the heat of combustion and transfer that to the piston, and if you are stuck with low compression because of unleaded junk then the gas doesn't know that you have alum or iron heads. So if the heads are transferring too much heat out of the combustion area it can't push the piston down as hard.

If you have two heads that flow identicle, have the same C/R and all elase is indentical than the iron heads are going to make more power. In order to recapture that power in the alum heads you have to increase the flow by 15% at every lift point or increase the C/R by 2 points.

Denny@JDS Induction Products
 
#28 ·
then let me say it a diff way, to make up the diff in power from alum head could you just tune it back in [ air fuel]-[timming]- an engine makes its most power at the edge of detonation, heat couses detonation, alumin cools the combustion chamber by leting the heat out, it would have to be the correct amount of air fuel but it would have to be right amount of timming and air fuel on the iron head to make peak hp
 
#29 ·
Kim & HeadDoctor

Let me see if I have a better understanding.

You can have 2 heads that will flow the same CFM, but factors such as runner length and cross flow (size of the port length and width??) will affect where the power comes in and stays, whether its averages more torque in the RPM band where a street engine will spend most if its time or if it comes in with more HP in the higher RPM where a more track oriented engine will use it.

So its possible for head A to flow 300 CFM and make 40 more ft lbs of torque from 2500 - 4500 RPM at the expense of top end HP than head B.

And for head B, which also flows 300 CFM to make 40 more HP from 4500-6500 RPM at the expense of some mid range torque.

That the purpose of a flowbench is less of an actual tool for the end user and more for the head designer and porter in that he is starting with a known number, ie. 300 CFM flow at a known amount 28". Then the designer/porter knows if any modifications made is an improvement or detriment based on the increase or decrease of flow from the base numbers or constant of 300 @ 28".

Is that somewhat more correct or am I still missing the boat?

The_Mustang

I agree, when Jay designed my cam, it was with the powerheads and stock ported intake. He also factored in that I may be adding a low boost SC or 125 dry shot in the future. I am very happy with the cam. When I started this thread, I was thinking of going with better heads as it would be 1 less thing I would have to worry about breaking in the future. When I started looking at heads, I was concentrating on flow numbers and was seeing that some of them were not that much better than what I had.

My car is a street car, in the almost 3 years I have had it, its never seen the track and is going to the dyno for the 1st time in 2 weeks. Think I'm gonna stick with what I have, add an SC to it and upgrade the valve springs.

I think this thread has some good potential though for info and would like to keep it going, just to learn more if nothing else.
 
#30 ·
That the purpose of a flowbench is less of an actual tool for the end user and more for the head designer and porter in that he is starting with a known number, ie. 300 CFM flow at a known amount 28". Then the designer/porter knows if any modifications made is an improvement or detriment based on the increase or decrease of flow from the base numbers or constant of 300 @ 28".
Exactly.

I had a customer report back the flow results of a Cobra intake (both pieces) that i had ported the lower for. The results were 236cfm average which seemed a little low to me - then I asked him to send the flow results of the stock intake which averaged about 195cfm - this told me that the net result had been about 40cfm which is right where I thought it should be. The net before and after numbers on the same bench are what counts - not the absolute number as they will rarley match from bench to bench. I've had other test results come back at 255cfm average - but the net was still in the 40cfm range. Both of those intakes would perform the same on the same engine.
 
#31 ·
I just wanted to add that my car felt like it had much more usable torque with the Powerheads/performer intake than my AFR 185s/systemax. Im talking about 1000 rpm-2200. It would kill the tires in second gear at 1200-1400 rpm easily but taper off as the rpms came up. Now its kind of the opposite, it wont spin the tires in second until it hits about 3500 rpm. Then it just smokes them until it hits the limiter. The car is faster now but I had more fun with the powerheads on the street. Dave.
 
#32 ·
I try to get this message across often - when most of your driving is done on the street where driveability and great low-mid range response is most often used, you want to keep the power band where you will use it most often. When some weeny in a Honda, Z car, Beemer, etc wants to see what ya got or trys to squeeze you off at the on-ramp, I like not having to rev the engine to 4,000 rpm to get into my power band. Makes too much noise and commotion if you catch my drift. The wrong kind of "cruiser" is more likely to take notice.
 
#33 · (Edited)
TRICKFLOW STREETHEAT
100 72 48
200 138 78
300 181 100
400 207 125
500 220 135
600 230 140
Not sure where you got those flow numbers for unported TFS High Ports, but here are the flow numbers for my 1.90 I x 1.60 E valve heads compared to the latested flow #s from Summit Racing for the new ones with 2.02 I x1.60 E valves.

My heads were fowed by a local shop which also did a competition vavlve job on them. The shop owner has years of experience with these heads and uses some on his combo.

New High Ports------------------Iron Street Heats

Intake 2.02---Exhaust 1.60-- Intake 1.94----Exhaust 1.60

.100....67...........55................63.......................58 .200...133.........103...............138.....................115 .300...186.........138...............188.....................146 .400...230.........166...............228.....................163 .500...257.........183...............254.....................172 .600...267.........193...............257.....................179