440 Dyno Results

-
PRH said:
Those fenderwell headers probably cost you some power on the dyno.
The extra long primary length tends to make the peak happen earlier than with more “normal length” headers.
Click to expand...

Well... There are a lot of variables here...

My headers are underchassis 2" TTI. These are 2 1/8 fender exits. 2 different styles, 2 different sizes.

Now if some power was left on the table, and his has often been called an unflattering dyno to begin with, I'm good with that. I mostly wanted a proper tune and a controlled break in. I also tried 2 different carbs.

You think those TTI's out perform the dyno headers? That actually surprises me.

Good thing is, he re-tunes your engine once it is in the car/boat etc. So it will still be dialed in perfect.
 
I’ve done a back to back test of normal length headers vs the 42”-ish primary length Hooker fenderwells at least twice(that I can think off the top of my head).
Both strokers....... both lost about 40hp by installing the fenderwells.
They weren’t 2-1/8” fenderwells though.

I also remember testing a SR headed 446 with a .625 lift roller cam with the owner’s fenderwell headers....... which were the only headers we tested it with, but I remember thinking it was down about 40-50hp from what I would have expected.

Where the long primary length excelled was in pumping up the TQ numbers below peak TQ.
At the beginning of the pull there were a few lines where the longer primaries were up about 40ft/lbs.
 
Last edited:
69conv said:
I would love to fit a wheel and tire combo under my Dart like that. What size and offset are you using? Did you do anything to the springs?
Click to expand...

15x4's up front. Maybe they are 3.5's I don't remember.

rear wheels are 15x11.25 with 3.5 backspace.

I relocated springs and minitubbed. The rear is narrowed as far as it can possibly be for a mini tub.
 
PRH said:
I’ve done a back to back test of normal length headers vs the 42”-ish primary length Hooker fenderwells at least twice(that I can think off the top of my head).
Both strokers....... both lost about 40hp by installing the fenderwells.
They weren’t 2-1/8” fenderwells though.

I also remember testing a SR headed 446 with a .625 lift roller cam with the owner’s fenderwell headers....... which were the only headers we tested it with, but I remember thinking it was down about 40-50hp from what I would have expected.

Where the long primary length excelled was in pumping up the TQ numbers below peak TQ.
At the beginning of the pull there were a few lines where the longer primaries were up about 40ft/lbs.
Click to expand...

well 642hp sounds ever better!
 
Are you planning on having it back in the car and running at the track before the end of the season?
 
PRH said:
I’ve done a back to back test of normal length headers vs the 42”-ish primary length Hooker fenderwells at least twice(that I can think off the top of my head).
Both strokers....... both lost about 40hp by installing the fenderwells.
They weren’t 2-1/8” fenderwells though.

I also remember testing a SR headed 446 with a .625 lift roller cam with the owner’s fenderwell headers....... which were the only headers we tested it with, but I remember thinking it was down about 40-50hp from what I would have expected.

Where the long primary length excelled was in pumping up the TQ numbers below peak TQ.
At the beginning of the pull there were a few lines where the longer primaries were up about 40ft/lbs.
Click to expand...

Yeah I've seen some weird results with the fenderwell headers also. I've run them on the dyno before and had the power curve look funky. I never thought that having the primary tubes too long would cause such a power loss but evidently it does. I had a 505 on the dyno the other day and we tried a Weiand tunnel ram on it. The tunnel ram cost the engine over 100 hp. The long small runners just choked the engine. So sometimes stuff that looks okay really doesn't work.
 
AndyF said:
Yeah I've seen some weird results with the fenderwell headers also. I've run them on the dyno before and had the power curve look funky. I never thought that having the primary tubes too long would cause such a power loss but evidently it does. I had a 505 on the dyno the other day and we tried a Weiand tunnel ram on it. The tunnel ram cost the engine over 100 hp. The long small runners just choked the engine. So sometimes stuff that looks okay really doesn't work.
Click to expand...



You'll also see weird stuff like you did with the TR when using stack injection. Too small and too long will drive the engine wild. They loose power and you almost can't tune them. It's hard to make them happy.
 
On a 500” build, the Weiand TR is probably tuned to about 5500rpm.

And when you reach the end of the tuned operating length on the Weiand TR, the motor will nose right over.
 
Last edited:
As for the headers........
This the only sheet I have handy for that:
Dyno headers:
600tq @ 4000
675tq @ 4500(peak)
718hp @ 6000(peak)
692hp @ 6700

Fenderwell headers:
658tq @ 4000
673tq @ 4500(peak)
678hp @ 5900(peak)
643hp @ 6700
 
PRH said:
Are you planning on having it back in the car and running at the track before the end of the season?
Click to expand...

I'd like to have it back together this season. It won't see the track until next year.
 
Best of luck. In re installing my motor I found a thousand little upgrades and minor repairs to do while it was going in.
 
PRH said:
The pic in your avatar looks like LVD.
Is that where you’ll run the car?

600hp in a Dart should be plenty to get you into the 10’s.
Click to expand...

You were right!

10.98@124
7.0@100

Geared all wrong, convertor wrong

More to come this season
 
PRH said:
There must be a dyno sheet you could post.
Click to expand...

I was actually looking for it today because I needed the tq@3500rpm for another post. NO dice. I think I have a hard copy in the glove box.
 
roccodart440 said:
3450 with me in it. (3150 curb weight)
Click to expand...
I'd say realistically you may have 2-3 tenths left in the combo once you get it all sorta out. My wife's car weighs 3120ish on the starting line with her little butt. Her engine made 535HP on the dyno. It went 10.70s at LV last year during bracket finals, but typically a 10.90ish car.
 
moparstud440 said:
I'd say realistically you may have 2-3 tenths left in the combo once you get it all sorta out. My wife's car weighs 3120ish on the starting line with her little butt. Her engine made 535HP on the dyno. It went 10.70s at LV last year during bracket finals, but typically a 10.90ish car.
Click to expand...

Going 10.70's on street tires and full street trim would make me a happy camper. I just want to finish getting it sorted this season.

I ordered new 4.10 gears and a 4,500 9.5" billet convertor. We'll see where it leads.
 
You must log in or register to reply here.
-

Back
Top