approx horsepower & torque

[metcoll]

HI Guys....just wanted some opinions on what I am about to do...440 with six pack replacement pistons, lunati240/250 @050 520/547 lift cam rpm heads (84 cc) rpm intake 800 dbl. pump carb 13/4 headers...heads just have a minor port job done..just wondering what I should expect...thx

[RECHRGD]

I'm not the expert here by any means.  But that seems close to the recipe people use in search of 500hp.  You may want to up the header size to 1 7/8".  You wont get many guesses here without your known compression ratio.  Depending how it's put together, you could be anywhere from 300 to 500 at the crank.......

[myk]

Yup, too many variables to consider.  Just throw it on the dyno...

[BSB67]

You hit the key motor build elements in what you posted.  Assuming that you don't do something dumb in the details, and assuming a good tune and full exhaust, I would put it at 475 on a not too happy dyno.  If you're really good at your tune, maybe a little more.

Your starting with a good basic package, it will run good.  If you want to up the ante a bit, I would consider a similar sized solid designed for a Ford lifter, 1.6 rocker, and beehive springs.

If you find any more money laying around that I can spend for you let me know. 

[metcoll]

I did dyno the combo on a dyno chassis dyno...it dynoed 330 at the rear wheels..this was with 452 heads stock size and just really a clean up on heads...just wondering if I would see 375 to 400 at the rear wheels... I do have a 4200 stall converter and 4.66 gears, which I am told will show lower numbers

[BSB67]

So are you saying that you already have the motor with those pistons and cam, and you are at 330 hp w/ 452?  You want to change the heads to the Eddys and hope to get to 375 - 400?

I think 375 is doable. Better flowing heads and higher compression sounds to me like it would get you there.

Your 2355 pistons, how far below the deck?

If you are going through this, it would be worth going the extra mile to try and achieve a 0.040" quench, and a 10.5:1 CR.  Both of these should be reasonably achievable.

[PRH]

The combo, as described in the first post, should easily make 500+hp with 1-7/8x3 headers.

[Calif240]

As a reference, since I'm 440 and standard stroke... I'm pulling a bit under 500 at the crank (getting much less at the wheels after 727 and DANA)...

440 Stock Stroke (+.030)
Ross Racing Pistons (similar to 6Pack I believe)
Scorpion Lifters
Comp Cams Roller Cam
Comp Cams Roller Rockers
RPM Intake
Aluminum Heads (similar to Edelbrock)

[HPP]

I did dyno the combo on a dyno chassis dyno...it dynoed 330 at the rear wheels..this was with 452 heads stock size and just really a clean up on heads...just wondering if I would see 375 to 400 at the rear wheels... I do have a 4200 stall converter and 4.66 gears, which I am told will show lower numbers

Figuring 18-20% loss with that converter and trans, you would be around 366 at the crank currently. It safe to say the change in heads could get you another 10-15 hp at the crank. Putting another 70hp down at the wheels will require more than a head change, IMO.

[BSB67]

20% loss with 330 at the wheels is 412HP at the crank.  Increased flow and increased compression ratio will have a noticeable and meaningful difference, IMO

[metcoll]

how much does rear gearing & stall converter effect rwhp...I have 4.56 gear & 4200 stall..i was told about 30 rwhp compared to say 3.55's

[HPP]

20% loss with 330 at the wheels is 412HP at the crank.  Increased flow and increased compression ratio will have a noticeable and meaningful difference, IMO

My fault, math error. But I get 396, not 412.

Agree compression increases will net the largest gains in power, but that is  much more involved than a simple head swap.

The paradox about gear ratios and hp readings on an inertia dyno  is the by  product of the calculation. It doesn't necessarily mean you are putting down less power, it is simply the speed you can accellerate the drum at which creates a torque curve the computer extrapolates into HP. It could be 15-20 hp low or high because of this. I'm sure someone with more experience can highlight this impact.

Remember torque is the work your engine can do, HP is the speed it can do it in.

Driveline losses, on the other hand, are real based on how loose your converter is and how much  power is sapped by the trans and rear end.

[BSB67]

20% loss with 330 at the wheels is 412HP at the crank.  Increased flow and increased compression ratio will have a noticeable and meaningful difference, IMO

My fault, math error. But I get 396, not 412.

Your math is still incorrect.  You're incorrectly adding 20% to the 330 HP value.  It is a 20% loss

[cdr]

20% loss with 330 at the wheels is 412HP at the crank.  Increased flow and increased compression ratio will have a noticeable and meaningful difference, IMO

My fault, math error. But I get 396, not 412.

Your math is still incorrect.  You're incorrectly adding 20% to the 330 HP value.  It is a 20% loss

Here is a chart

[HPP]

Gotcha. Thanks.

[BSB67]

The table is nice, but the math is simple and easy to remember.  An example best shows it.

Start with 400 crankshaft HP and 18% drive train loss in this example. 

400 x 0.82 = 328 rwhp

328 rwhp / 0.82 = 400 crank HP.

[c00nhunterjoe]

Either way, 400hp seems low for a 440 with ported heads and a big cam... was this dynoed in the rockies? Has the car been to the track for a mph reading?

[HPP]

IMO, I think the whole "six pack pistons" is the issue. That is a fairly broad claim that could be 11:1 or 9:1. Kind of like 3/4 race cam. Without knowing what their actual swept volume is against the certainly large chamber 452 heads, I'm willing to bet compression is down and coupled with the largish cam specs, its simply bleeding off its cylinder pressure. Some earlier posts are saying the cranking pressure is 150 psi. http://www.dodgecharger.com/forum/index.php/topic,121409.msg1508298.html#msg1508298

Playing with some online calculators with that cam, its possible the dynamic compression of this combination is lower than 8:1.  Smaller chamber heads, smaller duration cam, or taller pistons are, IMO, the ways around this lower HP reading. All have different costs, efforts,  and results. $1500 on aluminum heads to reduce chamber volume 25-30cc isn't going to result in a much larger bang in the cylinder and may only be worth 10-15hp increase but can be done in an afternoon. Similarly, a change in cam with reduced duration to build pressure could also result in a 10-15hp increase for only a few hundred bucks and take a weekend. Step up to some larger pistons may cost $500 or more depending on balance issues, but could also net a 50-70hp increase and may take months.

[BSB67]

Certainly more information would be good, but I think we still can make some reasonable assumptions to provide logical estimates.

2355 pistons and factory open chamber heads.  It will be 9.4:1, plus or minus 0.2. Could it be 9.8, sure, just unlikely.  Same with 9.0.

The OP stated for his current 452 heads: "....and just really a clean up on the heads...." .  Does he mean that the head was milled to make it flat (i.e. 0.010")?  Maybe.  Or did someone "clean up the ports"?  Maybe.  Either way, and I could be wrong, but generally this is code for "nothing meaningful has been done to the heads".   Usually when people spend $ to have a professional porter do bowl work, true comp valve grind and milling for compression increase, they don't call it a clean-up.  I'll bet dollars to donuts that the intake currently flows 220 cfm max. and the head is 90 cc.

Putting on Eddy heads will likely add 0.5 to the compression ratio.  Could be more, maybe less but unlikely.  The head will go from his current estimated 220 cfm to probably 265 cfm if he bolts them on out of the box.

This is the basis for saying he should be able to go from 330 to 375 rwhp, about a 55 crankshaft hp increase assuming everything is done right.