LD85

Anybody go the 18 degree heads yet, I'm sure someone has, but I probably missed it.

For my fall project,,, I'm tossing around the idea of 434 w/18 degree heads, single plane plane intake with @ 80mm throttle body intake,

cv67

I wish!

think there is a guy here with that same setup name escapes me (stevexxx?)
Pretty stout setup

Hes a regular sure he will post

LD85

I cant see a reason to build , just another 434, it needs some spice, although every component involved with 18-degree heads costs more, I have no problem in making this a piece by piece process.

Less than 5 miles from me is an excellent Cylinder Head resource, so that part would be easy, and I would thoroughly enjoy welding up my own header tubes

1991Z07

Not too sure why you would WANT to go that route.

Your engine @ 7K RPM's NEEDS 1,758 CFM. That would be about 280 CFM per cylinder.

A set of Brodix 23 deg. T1 M2's like I have flow 309 CFM's.

To convert to 18 deg. heads?

Custom Intake
Custom Headers

Both will cost you a BUNCH of money.

23 deg. intakes & headers?

LOTS of choices.

EASY decision...

bjankuski

It is not this simple. A 434 is definitely air flow limited and the better flowing the head the more power it will make (assuming a high performance build and not a low RPM stocker). At 100% VE a 434 will need 879 CFM (4 stroke has 1/2 the power strokes that you calculated) but since the head only has a limited amount of time to get air into the engine the better the flow the more power potential. A general rule of thumb is that a head that flows 309 CFM can support 632 HP and on a 434 it will peak HP at 6250 RPM if the correct parts are chosen. If you want peak HP to occur at 7000 RPM on a 434 you need cylinder heads that flow 350 CFM at 28in of depression.

LD85

I have no concern for the custom parts, they are more available than you might be aware, and i can weld the headers, so zero issue there,, and cost is relative.

Bending air on a 434 for an optimum performance is always a challenge, hence the SB2 / 18-degree heads. Also, my local shop M&M Competition Engines, @ 2 miles away makes SB2.2 exclusively

18 degree will make for HP than 23 degree on performance engines , that's a fact, fast cars are expensive, that a fact as well.

1991Z07

My heads on a 427 make 750 HP and 695 lb./ft.

That's a fact...my engine builder has done half a dozen of them, and dynoed every one of them. Mine will be built to run E85, so the compression ratio will be in the 12.5:1 range to get the most out of the octane rating of the fuel.

My calculations were a bit off, and after looking at it closer I posted this in another thread...

LD85:Understand why you are going that route then...if the builder is using that, then go with what they know best and you should be happy.

And I couldn't agree more about costs. It seems that you spend cubic dollars to get small gains sometimes...but you have to spend it.

It'll be interesting seeing the results of your project...

LD85

Tru dat!

All of the work on my first 3 engines was done here before the owner Bob, sold it to guys that used to work at INDY Cylinder Head, which is a premier MOPAR performance shop. i.e. Top Fuel etc.

http://mmcompetitionengines.com/

LD85

Spoke to my buddy at M&M, he says that a SB2.2 using Edelbrock Pro Port Heads, (they used to use the GM-011 heads) would cost $12k-$13k with me doing the assembly but with them blue printing the setup,,, and using a single plane EFI, tall deck block Dart Iron block, and hyd-roller, pump gas, 434CI.

I asked him for a ballpark power estimate and he said that he would "feel safe in saying @ 660-FWTQ and 675-FWHP range" , take it for what its worth

So, I'm stuffing the piggy bank and gonna put a freeze on gun purchases, my other hobby and go out and sale Automation Equipment like I never have before!

Today its a dream and I hope some tie after Thanksgiving, its a reality.

racebum

reading all this..can see the draw to 18deg heads, but, if you're going to do the fab work wouldn't using a turbo be almost smarter? you can set the hp level anywhere you want, can maintain a hyd valvetrain and do not need any trick engine parts..except a very solid bottom end and if possible inconel exhaust valves.

something like

http://www.youtube.com/watch?v=cccYWADbHPw

would not be all that hard to do

and another in action

http://www.youtube.com/watch?v=bpP20...eature=related

USAsOnlyWay

Why type of RPM is that going to end up turning?

Just another alternative which you could definitely build headers for, been getting that itch myself lately, LSx 454 or 500cid motor.

tpi 421 vette

The AFR 235's flow in the 340cfm range, and the AFR 245's flow in the 350cfm range, both 18 degree territory. And they use off the shelf 23 degree stuff, although the 245's require a shaft system.

LD85

A lot to think, no doubt!

cv67

Probably make more sense what Jim said more affordable.

Man the eye candy of an SB2...I get it.

Poverty sucks lol

bjankuski

The 245's should work well and save some money.

1989TransAm

"The AFR 235's flow in the 340cfm range, and the AFR 245's flow in the 350cfm range, both 18 degree territory."

I know what everyone is saying but I think there is more to this from my experiences. Comparing my motor to the LSX series I am down 30+ horsepower. Here are my stats.

1) 369cubes
2) 11.12:1 compression ratio
3) 280/280-233/233 camshaft on 113 LSA, .594" lift at valve.
4) AFR 210 heads modified by DR J., Flow 305cfm at .600" lift on his bench. Speed at the pushrod pinch is 315fps. 2.08/1.60 valves.
5.) Intake flows 336 cfm with maximum with max airspeed of 300fps at peak horsepower rpm of 6500rpm.

Everything is there and the best I can do is 420rwhp/417rwtq. If this was an LSX combination with the same exact specs I would be well past 450rwhp. IMHO I am thinking that the 18 degree and 15 degree heads utilize the available CFM better in creating horsepower. In other words it is much easier to make the power with the 18/15 degree heads than the 23 degree heads. I am still wrestling with this and found this thread quite interesting as I am looking into it myself.

LD85

I 100% agree! Look at how many engines are built with 23-degree parts and very rarely do I see "exceptional" numbers, and most times, the numbers are just flat out less than anticipated,,,, the math tells us one thing, and the result reveals something else.

The best engines I can recall reading about always seemed to have hi CR, and the ones that had crazy good numbers, well, I was always suspicious of those.


At this point, i.e. today, I don't see myself spending $12k but the engine in my car has probably only @ 10k miles on it, so I am in no rush, I'll read and study about this more, lots to consider, hood height and clearances etc.

The only custom part is the headers as far as I can see, everything else is off the shelf, although the heads are ported by a CNC , just as many others are. So off the shelf yes, and costly yes yes!

LD85

Also, I agree that there are less costly options, if I had to do it on today's budget, I would buy a Dart SHP block ($1500) or Little M, and then throw my forged 406 parts into it, and add a blower or SC.

bjankuski

I do not necessarily agree that there is anything magic with the LS heads that create more power than a similar flowing SBC head. The plain truth is that most LS heads outflow a SBC head and not until you spend big dollars on real good SBC heads will the engine make excellent power. I chassis dyno and tune approx. a hundred cars a year and always study the combination of parts in each car. The conclusion I have come to is that when the engines are equipped with similar power making parts, the engines will make similar power. It just takes more money to make a SBC perform at the same level as a LS engine with stock or near stock parts. You add a cam and headers to a LS 6.2 and it will knock down 450+ RWHP but it has heads that flow 330 CFM at .600 lift along with good supporting hardware from the factory like windage trays, excellent intake manifold, and 90mm throttle bodies.

I am not sure what your goals are but your combination could benifit from a cam with a tighter lobe seperation and more duration. It will idle rougher but it will hit harder and make more power if the cam was changed.

bjankuski

I am not saying a engine with heads like yours cannot make 750 HP, what I am pointing out is better flowing heads will make power more easily.

A rule of thumb is (intake flow X .256 X 8 = HP potential of a high performance street car), (intake flow x .280 x 8 = HP potential of a competition built engine designed for racing with limited on no street use), (intake flow x .311 x 8 = HP potential of an all out drag race engine, no compromises)

HP street (309 x .256 x 8) = 633 HP
Competition (309 x .280 x 8) = 692 HP
All out, no compromises (309 x .311 x 8) = 769 HP

These are rules of thumb and should only be used as that.