Two step headers and rpm range?

[gregsdart]

The motor dynoed 847 hp, and i got maybe another 30 hp with some changes to get down to the best ET i have run. So 875 would be about what should show up on a properly calibrated dyno. Thanks for the input and direction. I an not sure how to deal with the possible "ledge" if the head port opening is bigger than the primary called for? Packaging this deal is going to be a challenge due to a 2x3 chassis with little room for a collecter, which is why the current one is short. I had to terminate it. Angling down behind the front tires. I am going to investigate how well a flat extension on the collecter might work like i have seen on some stock car exhaust tubing? I will do a form for Burns and see what they say as well.

[cjperformance]

What is mcsa of your exhaust port and what is the csa of your port at the flange?

[gregsdart]

1.76 wide by 1.54 high. 2.71 aquare inch for the exhaust port. The header flange is a bit bigger, can't get to it at the moment.

[exhausted]

1.76 wide by 1.54 high. 2.71 aquare inch.

Ok, if it was square, which it probably is not, than it is even smaller than that. 2.0" 18ga is 2.80 so I don't see a problem with that.
The header is larger than that but if it is shaped wrong an the roof of the port is smashing into the header flange, would you do that on your intake port? It will hurt power upstairs a lot. so start there, check it.
Also, I don't usually comment on things other than exhaust systems but that seems like a lot of duration for the rpm band or power for that matter. But as I say, it just surprised me. I never had a motor that big, so.

[cjperformance]

1.76 wide by 1.54 high. 2.71 aquare inch.

Ok, if it was square, which it probably is not, than it is even smaller than that. 2.0" 18ga is 2.80 so I don't see a problem with that.
The header is larger than that but if it is shaped wrong an the roof of the port is smashing into the header flange, would you do that on your intake port? It will hurt power upstairs a lot. so start there, check it.
Also, I don't usually comment on things other than exhaust systems but that seems like a lot of duration for the rpm band or power for that matter. But as I say, it just surprised me. I never had a motor that big, so.

Looking back some posts OP said the primaries at 2 1/8" required a lot of enlargement to fit the port face/header flange. Could be a difficult port to get down to the right primary diameter. 2" x 18g is plenty going by hp and mcsa, cant wait to hear port face csa!, may be hard to get a transition here that wont hurt more than smaller pipe will help

[exhausted]

1.76 wide by 1.54 high. 2.71 aquare inch.

Ok, if it was square, which it probably is not, than it is even smaller than that. 2.0" 18ga is 2.80 so I don't see a problem with that.
The header is larger than that but if it is shaped wrong an the roof of the port is smashing into the header flange, would you do that on your intake port? It will hurt power upstairs a lot. so start there, check it.
Also, I don't usually comment on things other than exhaust systems but that seems like a lot of duration for the rpm band or power for that matter. But as I say, it just surprised me. I never had a motor that big, so.

Looking back some posts OP said the primaries at 2 1/8" required a lot of enlargement to fit the port face/header flange. Could be a difficult port to get down to the right primary diameter. 2" x 18g is plenty going by hp and mcsa, cant wait to hear port face csa!, may be hard to get a transition here that wont hurt more than smaller pipe will help

Yeah well the ports on the Wedge head are really wide so that is what he refers to as stretching the tubing. As long as he doesn't intrude into the port anwhere. He is probably having to use a really tight radius off the head and if not done carefully then all bets are off. not my fault the chassis kills the header, story of my life...

[exhausted]

It has always amazed me how much effort is put into designing exhaust ports and working em to death on the flow bench and then give the engine to a header that just screws up the transition from port to tube a few inches from the valve where the velocity of the gases is the highest. It just kills things, and everything else downstream you try or do don't seem to make much difference. Well you already killed the header. Horsepower here is all about flow, you can't put a 2.5" radius tube off the head on a exh port that has a 3" radius, eh? and then if the port shape is distorted, ie not round, and you have to change direction of the flow at an angle down or whatever...if you look at it like a port and want to get it to flow most headers break every rule.

I have told this story before elsewhere here, but the very first cup header I built was for the 26 car and it was the same size tubing 188@12-200@12-2.12@12', straight 3" collector. Virtually the same "size" header. The only difference was it was 6 separate tubes, (middle are 2 tubes), which allowed me to use larger radius tubeing off the head and the radius' were not "cheated" , nice and smooth compared to the Stahl header. Oh and I took off the port adapters which gave me an extra 1/2 of room to the first obstruction on the tubes. 18hp when the engines were making about 675hp at that time.
It was like sex. Understand the only difference was the transition from head to tubing, and it was a bit smoother the rest of the way, but hello? By about a year later I had found out I could build a header using everything a 1/8th inch smaller and make the same power or more and the torque was way up.
Then we started not worrying about equal length so the header could be even smoother, more power. Then the 421's, bang, more torque and power and you could run bigger lobes. Its all in there and it is a lot more than tube size and length.

[cjperformance]

Ok, if it was square, which it probably is not, than it is even smaller than that. 2.0" 18ga is 2.80 so I don't see a problem with that.
The header is larger than that but if it is shaped wrong an the roof of the port is smashing into the header flange, would you do that on your intake port? It will hurt power upstairs a lot. so start there, check it.
Also, I don't usually comment on things other than exhaust systems but that seems like a lot of duration for the rpm band or power for that matter. But as I say, it just surprised me. I never had a motor that big, so.

Looking back some posts OP said the primaries at 2 1/8" required a lot of enlargement to fit the port face/header flange. Could be a difficult port to get down to the right primary diameter. 2" x 18g is plenty going by hp and mcsa, cant wait to hear port face csa!, may be hard to get a transition here that wont hurt more than smaller pipe will help

Yeah well the ports on the Wedge head are really wide so that is what he refers to as stretching the tubing. As long as he doesn't intrude into the port anwhere. He is probably having to use a really tight radius off the head and if not done carefully then all bets are off. not my fault the chassis kills the header, story of my life...

In an ideal world, intake sizing then matching port, and ex pipe sizing/logistics then matching port for a given hp target would be great starting points.

[gregsdart]

To stear clear of tight turns off the flange, all tubes on my current set of headers come straight away from the heads then angle up gently to go OVER the front of the chassis, not through it. I needed that extra length to get everything to fit , including a collecter.
Flanges for stock 440 heads have smaller port openings, and i will be looking at them to use to get a better transition or match if i build another set. From the looks of the ports the exhaust gasses leave the port at an angle of maybe 10 degrees up rather than straight away. I can kill two birds with one stone if i fit those tubes to match that angle. A better port exit, and a bit more length before i have to use a bend.

[maxracesoftware]

I have an rpm spread max of from 6,000rpm to a max of 7450 shift and trap rpm on the data logger, and am asking if two step headers help in a some what narrow rpm spread? Auto trans, 2.45 low 1.45 2nd, 1/1 high. 2 1/8 to 4 inch collecter currently, best of 8.77 at 153 at 3055 lbs.

I don't mind my thread going off my topic some,
but would like some general input on possible gains in ET,
or some idea if my headers are way out in left field.
So here is a bit more info, and i know the answers are not going to be guarantees of gains,
just opinions on limited info on what MIGHT be possible gains, or better to leave the headers as is.
So i ask for your opionions.
4.15 stroke 4.500 bore 528 cubes, single plane large port 3x Indy Intake on ported 440-1 heads,
Jones inverted flank rollercam, 284/296/114 with .870 gross intake lift, .800 exhaust.
In at 110. Alky injected, 15/ compression,.
Exhaust ports on these heads are large,
and the header flange required a lot of enlarging of the 2 1/8 pipes to fit. the flange,,
and match the port. 2 1/8 tubes are 28 inch to the collecter from the head.
No or little pinch in the collecters, about nine inch from pipe to end of collecter.
I have run 8.77 at 153 at 3055 wieght,
2.45. Low gear Torqueflite with 1.45 second, 4.56 rear gear
with 33 inch tall by 15 wide Goodyears.
Launch at 5,000 off brake, flashes to 6,000 in low, shift at 7450 drops to 6200,
2/3 shift at 7300 drops to 6200, 7450 at stripe.
So again, any idea if there may be more that say 15 hp hiding in this deal?
1965 dodge Dart, 528 cu in wedge, 8.76 at 153 mph best. 3050 lbs

The motor dynoed 847 hp, and i got maybe another 30 hp with
some changes to get down to the best ET i have run. So 875
would be about what should show up on a properly calibrated
dyno. Thanks for the input and direction. I an not sure how
to deal with the possible "ledge" if the head port opening
is bigger than the primary called for? Packaging this deal
is going to be a challenge due to a 2x3 chassis with little
room for a collecter, which is why the current one is short.
I had to terminate it. Angling down behind the front tires.
I am going to investigate how well a flat extension on the
collecter might work like i have seen on some stock car
exhaust tubing? I will do a form for Burns and see what they
say as well.

the Headers you now have look very close to what you need
here are some 2-Step and 3-Step Header Specs for you to look at
as well as Simulation Data of your Engine ...

[maxracesoftware]

your Cam Specs are very close too !!!

[gregsdart]

Thankyou! I get a big kick out of all the help and knowledge available now days. I am 69 years old. I especially appreciate you guys that are willing to help on a forum like this! From showing me how to keep my stuff alive, to how to make serious (for me at least) power. !!!!