Aluminum vs Iron compression on pump gas

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Mad Dart

Mad Dart

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Question, would you say that 10.75:1 Iron Head on pump fuel would be the equivalent of 11.25:1 Aluminum Head on the same fuel?? Dont want to run race fuel but I will if needed, it is sold at the pump where I live.

I am about to throw down some cash on my heads and intake, I would like some input.

I HAVE ALL OTHER PARTS EXCEPT THE HEADS AND INTAKE.

I will be buying this week and it is between the Fully Ported EQ Magnum Heads with BEEHIVE springs and fully ported Edelbrock Heads with same springs.

Quench will be in the .034-.036 range with either head.

Eq Heads are 62cc at 10.75:1 and I can take them down to bring compression up more but dont think it is needed.

Edelbrock Heads 58cc Comp is at 11.20:1

Cam is 256@50 Hughes Solid Flat tappet 106 LSA

Also I was going to run the Eddy Air gap port matched but I am leaning toward a Victor Jr as same.

My combination should be really close to 600hp with tq close.

Been working on this build for about 9 mos and it is time to finish it.

I do not baby my cars, I run them very hard. Street/Strip use.....

I used a program and it says cylinder pressure will be in the 190-200 range

This is a 4spd..............

Your Thoughts??
 
I have stock magnum heads (measured at 64 cc) and zero deck flat tops for 10.6:1 compression and 190 psi of cranking pressure. I run a 224/230 @ 0.050" cam, the quench distance is 0.039". The magnum heads are a much more efficient so they don't require as much total timing, I run 33 with 17 initial all in at 2500 rpm.

I run 89 octane on this setup and have run 87 in a pinch but it will detonate under 3000 rpm if you are not careful.
 
I would say that with that large of a cam, you should be OK, even with the tight lobe centers. I would most certainly run premium fuel though until you have everything sorted out, then you can experiment with different fuels. Good job on getting the quench right too. :)

Technically, iron will make more hp than aluminum but aluminum is easier to port and is lighter and will take 50lbs off your front end so it's a toss up. Aluminum also dissipates more heat which is both good and bad. If it were my car, I'd go with the eddys.
 
Dgc,

Is yours a stroker ??
And if you could tell me your elevation?

My Cam will not make enough vacuum so the canister has been removed.
I had the dist redone by Don at 4secondsflat.com FBO systems.
He is saying my initial timing should be set at 24 degrees and the mechanical advance is set to 34 degrees at 3400 if I am correct. I will need to pull out the card and check it. I will check it later today and post if I am incorrect. My cam has .614 intake lift , 256@50 the exhaust is .624 260@ 50 with the intake valve closing ABC at 51 degrees.

This is with the eddy heads.......

Then the Eq's
 
The EQ heads are good but I would go with the Edelbrocks because of the lighter weight.
 
This is another problem.

I am switching to magnum oiling. So the Edelbrock magnums will need to be machined at a cost of $200.00 to accept LA intakes. If not I will be stuck with 2 intake choices for this combo.

1) Eddy Air Gap
2) M1

Unless somebody knows something that I dont?? Help here...........
 
The crosswind is dual pattern also..if not get the EDDY
 
Here are a few pictures of what I have put together so far.

photo-9.jpg

photo-1.jpg

photo-9.jpg


photo-1.jpg
 
74,

Where do you get a Crosswind?? Is it dual or single plane?

Do you have a link or something to it?

I think you live about 25 minutes from me, I am in Murrieta ca
 
IIRC, the Crosswinds intake can be purchased through Jegs or Sumitt racing. Sumitt's brand is the crosswind intake, it's a dual plane Edelbrock knock off with dual bolt holes for regular LA and Magnum heads.

IMO, I would run the single plane intake. A M-1 would be fine. It is a capable intake.
 
Rumble,

Do you know the M1's RPM Range? Where does it start to come on at vs the dual plane Air Gap? Air Gap is 1500-6500? I know the Victor Jr is about 3000-8500..............But I may be incorrect.
 
Well, no, but, hummmm, If I look in the old performance tips sction, the M-1 single plane intake is recomended to the 11 second bracket. Now, I'll turn some pages to the recomended cam for 11's ... flip flip flip flip...


A mechanical 655 for the 11.5 and the 657 for the 11 second build. Flip flip flip flip flip

655 specs out to be; 296/.557 with a duration @ .050 of 251.6
657 specs out to be; 312/.590 with a duration @ .050 of 265.2
(Hummm, big cams and I'll take a stab and say 3,000 - 7,000 rpm)

Hummmm Now, if I go over to Comp Cams to kind of match up the duration @ .050 specs to there extreme high lift cams for a comparo... Click click click....

Hyd. 3000 to 6800 20-229-4 XE295HL 295 307 251 257 .564 .564 110º
Oh wait, that's a Hyd. but I'll leave it up for food for thought.

.022 .022 3000 to 6500 294S 294 294 248 248 .525 .525 110º
OH wait, that's a Magnum cam. Hummm, take notes now..... scroll scroll scroll

Heres the drag race cams;

SOLID-3500+ converter inin 340. Needs single plane intake and
10.5:1 compression. Excellent low end and mid-range torque.360 or 3800+

.020 .022
3500 to 6500
(Adv. duration / @ .050/ ....lift/ .........centerline)
281 299 ..........252 262... .542 .555 ...106º




SOLID-318-340. 4000+ stall 750 CFM,manifold. 4.88 gear. 10.5:1 & up
compression.
.026 .028
4000 to 7000
290 290 255 255 .540 .540 106°

SOLID-Best all around bracket cam. 4000+ converter in 360 or 4300+ stall
in 340, min compression ratio is 11:1.

.020 .022
4000 to 7000
290 304 260 266 .558 .555 106º

SOLID-4500 converter in 360 4800+ stall in 340, 11.5:1 compression.
.018 .020
4300 to 7400
312 266 274 .570 .572 106º


SOLID-Good Super Street or fast bracket cam.Works best with 12:1 compression and 5000 + converter.

.018 .020
4500 to 7500
300 316 270 278 .579 .578 108º

Take it for what it's worth.
 
Rumble,

Dang that is alot of information. I really appreciate you taking the time to go WAY over the extra mile.......
 
i seen 600hp I say go with the EDDYS and port match the M1
 
To copy and paste is easy. Actually, a peice od cake.. Now that BJR posted up the RPM range, it sounds right, like I seen it before. I know I seen it before but just can't remember where I seen it or remember it when the post came up.
Even though I agree that's the range Mopar gave it, I don't dopubt for a second it'll go to 7,000.

If you compare duration @ .050 numbers, they all fall within the intakes RPM range preety much. Do note that the MoPar cams have the highest lifts and durations are calced at Advertised duration X .850 making them a preety quick ramp cam with superoir lift. Not all of the Comp Cams listed rise that quick while others rise quicker. This cn be seen in the difference in the advertised duration vs. the duration @ .050 difference.

Not the XE Hi-Lift cam is very aggressive in it's numbers but is softened by the Hyd. lifter which broadens the RPM band. (That's a hyd lifters advantage.... in a way. LOL, the pro's and cons of cams.
 
Mad Dart I'm curious as to why your switching to magnum style valve train? LA head rocker shaft system is superior IMO. Do you plan on running a girdle on the rockers? That's going to be quite alot of stress on a 5/16" rocker stud.
 
fishy68 said:
Mad Dart I'm curious as to why your switching to magnum style valve train? LA head rocker shaft system is superior IMO. Do you plan on running a girdle on the rockers? That's going to be quite alot of stress on a 5/16" rocker stud.
Click to expand...

Fishy,

I bought some parts a while ago, the 1.6 Roller Rockers, JOMAR GIRDLES studs etc, and decided to use them on this build. Plus I wanted a CLOSED combustion chamber and attempt a tight quench and run higher compression and bigger camshaft on PUMP fuel if it is possible. I understand that there will be more stress and hopefully the use of BEE-HIVE valve springs will help with this issue.

I really got caught up on the EQ heads and how much flow was available for an Iron Head without the CRACKING issue compared to stock casting Iron Heads.

I hope this explains.
 
fishy68 said:
Mad Dart I'm curious as to why your switching to magnum style valve train? LA head rocker shaft system is superior IMO. Do you plan on running a girdle on the rockers? That's going to be quite alot of stress on a 5/16" rocker stud.
Click to expand...

Fishy,

Also if I was to do it all over again I would have stayed with the LA style edelbrock heads. There was an extra cost with the JOMAR GIRDLES,,,,,,to get everything to clear I had to get TALLER valve covers and it will certainly take away from the STOCK appearance. I was going to make an adapter for the heads and run the LA valve covers........just to be incogneto but cant do it now............there is just too much room that is needed.
 
Is this a 4" arm engine? Stay away from the Crosswind if that is your goal. It cant move enough air.

I'd go with the RPM Magnums with the smaller chamber. The aluminum will help with the pump fuel. But, you could run a much bigger cam if this is a 4" stroke engine. I have a hard time seeing you getting anywhere near 600hp with a 256° cam, regardless of heads or lift. Like was said, smaller chambers, good quench, mean less total timing.
 
you'll be in the 550+/- range if you can pick up port volume.jmo

More lift would be nice if you are gonna run a flat tappet and achieve 600.jmo

An actual 'after lash' .588 '+' lift is what I expect to see in a 600 hp 4''arm build.
11.1+ comp too.

sounds good though, have fun!
 
1wild&crazyguy said:
you'll be in the 550+/- range if you can pick up port volume.jmo

More lift would be nice if you are gonna run a flat tappet and achieve 600.jmo

An actual 'after lash' .588 '+' lift is what I expect to see in a 600 hp 4''arm build.
11.1+ comp too.

sounds good though, have fun!
Click to expand...

Yes it is a 4" arm. I am using 1.6 Rockers Lift is .614 before lash on the intake and .624 for the exhaust. This is a flat tappet solid cam also. 600hp is just a number and don't mean anything if you cant actually get the power to the ground. I am just excited to be able to finally get it finished. I will be telling everyone it is a 318 anyway.......haaaaaaaaaa
 
moper said:
Is this a 4" arm engine? Stay away from the Crosswind if that is your goal. It cant move enough air.

I'd go with the RPM Magnums with the smaller chamber. The aluminum will help with the pump fuel. But, you could run a much bigger cam if this is a 4" stroke engine. I have a hard time seeing you getting anywhere near 600hp with a 256° cam, regardless of heads or lift. Like was said, smaller chambers, good quench, mean less total timing.
Click to expand...


I want to learn something, when you say smaller chambers, good quench means less total timing.......does this equate to less power?? I would like to know......

Thanks.
 
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