Anybody here using the Pipemax app, or other software to build headers? I have a coupke recommendations from Koeffel's Place, but since it is an endurance application and kind of odd I'd like to run the numbers. Mr_P_Body Mike offered a while back, but I didn't have the numbers I needed at the time and he hasn't been on here in several weeks, hope he is ok.
If you can and care to help, please let me know. Thanks, Jerry -numbers below

volumetric efficiency if known -unknown, but estimating 105%? Your guess is probably better than mine.
bore 4.500
stroke 3.915
rod length 6.7"
compression 14.9:1
peak hp rpm - hasn't run, say 7500+-
valve diameter 2.40 Ti Int, 1.78 Ex
valve stem diameter .3142"
valve lift .879 Int @1.75, .850. Ex @ 1.70 T&D rockers
duration @ .050 282 Int, 303 Ex
LSA 114
degreed center line 112
flow of the heads
Lift.  L/D    Int.   
.500  .208.   357    
.600. .250.   394   
.700. .292.   425   
.800. .333.   443   
.900. .375.   454    
1.0.  .417.   456
Lift.  L/D.   Ex
.500.  .281.  243
.600.  .337.  274
.700.  .393.  299
.800.  .449.  312
.900.  .506.  319
1.0.   .562.  336
exhaust port length of head- 2 7/8" measured as far into the port as I can get a tape measure past the valve stem to the far side of the pocket, to the bottom of the port exit as installed.

I'm thinking the RPM will be more like 8000+ Jerry. What do Pete and Chuck say? They would know. It looks like a great combo.

I have your info, but can't make it small enough to post. What measures do you need?

Here ya go. Didn't know your ex centerline length, so 3.2 is the default.

Hey Tom, they said I'm overthinking it...they gave me some sizes and lengths and set build them and they would be fine.

Thanks Mopar Dave, really appreciate your time. Is that Pipemax software or something else? Hope those hp numbers are a little pessimistic, I was hoping for 950hp+ with good tq numbers. I should know sometime this year! The numbers are about the same as Koeffel's team provided...guess they've done this before!

Mopar Dave, couple more questions. What constitutes a "tuned" collector? I am considering a merge collector into a straight exit (non-megaphone) vs a formed straight collector. Also, do you kmow if the collector has to be straight, or is it only the length and diameter that is critical? I want to do side exhaust old school NASCAR style to help deflect some air around by rear wheel openings with the tips just behind the door openings. Trying to break a 237.3+ mph record. Thanks.

Someone here knows more about that than I, but merge collectors need to be tuned to your combo on a dyno. I tried some $600 merge collectors once without dyno tuning and found nothing on my slip. Those things sure are not cheap. oh yeah pipemax

Thanks, I was tracking the same about having to be tuned significantly to your combo. Man, they are cool looking though (when you are under the car to see them)!

How about using a set of boom pipes off of a NASCAR cup car?
I wouldn't run them both out the same side though like NASCAR does
I still haven't got to go watch at Bonneiville yet Let me know if your going and maybe I can come watch for a couple of days

I think I've said this before but this is a nice build and I appreciate you sharing everything. Also, I think you choose a good builder, one of the worst things you can do is veer off the course of what the 'team' your working with is guiding you on IMO. I'd trust what they told you to spec dimensionally for tubes. I also think given the parts you are listing that, the power will be well above 1000HP. I'm really eager to see the plumbing on these...If they are class legal you may do better with a fender exit collector.

I have built several headers using pipemax software, it works really well. If you have the room and take the time, I see improvements by building the step headers. I like fenderwell style headers because it makes stuff easy to work on, so I just choose a longer harmonic, and again it always makes good power. I personally have had good luck on my drag car with the old style Hedman 4 into 2 into 1 style collectors which make more low rpm rang torque. My racing buddies made fun of my old school collectors so I tried some of the merge style and the car slowed down. I would think on a land speed car you would want just a good 4 into 1 standard style collector. And on the projected HP numbers, most of the engines I build come up at the average HP number generated by pipemax. I also use performance trends engine software and it hits within 10% error when I dyno the engines.

I agree that pipe is a good tool but, I haven't reviewed the inputs to know that it is giving an appropriate 'output' but at a glance I noticed it recommended 2" initially...that is too small!...also I noticed AT A GLANCE that it is only predicting a peak of 925ish HP and that is IMO, not accurate.

If you input a larger volumetric efficiency number you will get bigger hp numbers, but then how accurate is that? If we only knew the correct VE numbers to input to start I think the output numbers would be more accurate. junk in junk out.

I agree with most everything said here. You will make over 1000HP easily, just up in the RPM range, 8000 and above. Volumetric efficiency is everything and I don't have my dyno sheets available right now but would be willing to share what my stuff has done in the past. The guys that are building your engine are top drawer from everyone I know that build high end engines so listen to them as pointed out. I would think for a land speed application that merge collectors would be a waste of money but you also know people that would know. Most of us on this site are drag racers and that's a totally different dynamic than having a few miles to get up to speed. I'm thinking with the right tune up, you will break records.

I’ve never used that program, but I’d try tweaking the inputs of VE and peak rpm until the predicted flow requirements get closer to the actual head flow.
The current read out is only looking for a head flow capacity that’s 50cfm lower than what’s available.

Based on the old superflow formulas, a 499 with heads that flow in the 440 range should be able to peak in the 8400-8800 range.

Using the 387cfm number the program spit out puts the estimated peak at 7400-7800.

garbage in garbage out. If you have the head flow numbers, pipemax has a calculator to predict volumetric efficiency. which helps get the numbers closer. I mainly use it to predict header tube length as the program calculates the resonance of the gasses, which plays a big part in tuning the headers to the cam and intake to make them work together. 1000 hp is around 2 hp per cubic inch for the combo mentioned, you have to have all your ducks in a row to make that level of power. Again all the computer programs made are just tools to help you get the combo close. Then time on a dyno gets it better, then the race track tuning gets it as good as it can get. I personally have never made 2 HP per cubic inch with out some dyno time and changing a few parts and playing with cam timing.

Like I said........ never used the program....... but the head flow numbers are in the first post.

If I use your max flow number(454) PM shows 124.37VE and 1138hp/848.9tq.
If I use 425/.700"lift PM shows 118VE and 1065hp/812tq
If I use 394/.600 lift PM shows 111.24VE and 987hp/758tq
Looks like pipe diameter is 2" with the 394 flow and 2.146 with 454 flow number.
Hope that helps. If ya have a specific VE number let me know. Only takes a minute.

Just noticed at the bottom of your page ex port length. I don't see well any more. I'll rerun some numbers later and see if they change with the longer port. I don't expect them to change much. They didn't on my head.