Jay or Barry or Others. Need help choosing proper header size for a 482

[TimeWarpF100]

If it was me, me would just get a set of them truck headers Jay used in his book/test.
They made the most power and where the cheapest.

I have a set of them but the port is all wrong. I know I could fix it but the collector is in wrong place, pointing in bad direction. Instead of modifying those new 1 3/4" truck headers I will put them on next project a 416 FE into my other daily driver 1966 F100 which will most likely get Jays intake base & who knows . .

By the way Jay never put them on anything larger than the stroker 390 best I can tell. But they did work well on a 425hp engine. I think I will be making a tad more than that. LOL

[My427stang]

OK, so I read your cam stuff wrong, thanks for clarifying.

With your additional info, I am not sure I would change anything.  If anything, I may just tight lash it.

Here is why.

1 - The lift should do will with your heads and intake
2 - The tight LSA will make a lot of torque and mid range, probably be downright brutal
3 - The advertised duration is a good match and is high enough to carry the power through what you'll be using if for (gears and truck weight)
4 - Its in there already, always easier than changing
5 - DCR is at 8.12, which is about perfect.

I know .050 sounds  low, but I am not sure it would be worth a cam change without going converter/gearing changes, because the rest matches pretty well.  I think I'd run it, it's not like it'll be tough to do a cam change later if you really hated it, its a F-series.  At worst depending on year the grill and radiator has to come out.

That overlap and 10.41 compression should sound like a monster,  should run well on pump gas, and pull hard. Your comment about get in and drive it makes a lot of sense and this will do well

[TimeWarpF100]

OK, so I read your cam stuff wrong, thanks for clarifying.

With your additional info, I am not sure I would change anything.  If anything, I may just tight lash it.

Here is why.

1 - The lift should do will with your heads and intake
2 - The tight LSA will make a lot of torque and mid range, probably be downright brutal
3 - The advertised duration is a good match and is high enough to carry the power through what you'll be using if for (gears and truck weight)
4 - Its in there already, always easier than changing
5 - DCR is at 8.12, which is about perfect.

I know .050 sounds  low, but I am not sure it would be worth a cam change without going converter/gearing changes, because the rest matches pretty well.  I think I'd run it, it's not like it'll be tough to do a cam change later if you really hated it, its a F-series.  At worst depending on year the grill and radiator has to come out.

That overlap and 10.41 compression should sound like a monster,  should run well on pump gas, and pull hard. Your comment about get in and drive it makes a lot of sense and this will do well

Thanks for your Input!

Its all about the torque for me on this truck. It will seldom see 5-6000 rpm. Typical will be off idle to 3-4000 rpm. If I have to give up a few HP on higher end is ok by me.

I had initially wanted to make 600hp but with the way its setup as long as it has a nice torque band.

Any estimates on HP? TQ?
My Dynomation Software is showing 600 TQ @ 4000 RPM and 580HP @ 5500 RPM
Its showing 40HP gain just in the intake mod.
Software saying 500 TQ will start around 2000rpm.  In the past have found it quite accurate as long as I have accurate inputs.
Shows 500 + TQ from 4000~around 5700

I ordered the newest software and it should be here today. Fun to mess with and will be interesting to compare when I get it on the chassis dyno.

Sound, Torque and drivability are my top 3. Reliable of course too.

I have had enough of the gotta spin a high RPM for power . . . LOL

[My427stang]

My electronic guessers are saying around 540 hp at 5200 and between 560-580 ft lb at 4200, above 500 from 3000+.  I'd guess those numbers  at the high end, but it should match your desired RPM pretty well.

It's such a unique cam for a 482 I hope you try to use it and see what it does.  The tight LSA should help the torque and make a nasty sounding idle.

I went the other way with my truck 445, about the same .050 duration, lift, and a 104 intake centerline, but spread the centers t0 112 to make it idle smoother.  It runs GREAT and I don't have the headers, intake or head you have.

[TimeWarpF100]

My electronic guessers are saying around 540 hp at 5200 and between 560-580 ft lb at 4200, above 500 from 3000+.  I'd guess those numbers  at the high end, but it should match your desired RPM pretty well.

It's such a unique cam for a 482 I hope you try to use it and see what it does.  The tight LSA should help the torque and make a nasty sounding idle.

I went the other way with my truck 445, about the same .050 duration, lift, and a 104 intake centerline, but spread the centers t0 112 to make it idle smoother.  It runs GREAT and I don't have the headers, intake or head you have.

I know its only bench racing but I have my newest dyno software loaded and the initial info inputs done. Not quite finalized as need to do the compression math part but manually input of actual comp.

Ross, Can I email this info to you to see what your thoughts are?
Now I can mess with all kinds of stuff I could not before.
I have done them before on a earlier version then went to engine dyno then to chassis dyno and found them very very close.

Hopefully I will soon find out. Its fun to mess with if nothing else.
All in all a lot of parameters I can mess with.

I will then go to a chassis dyno to see if numbers are in ball park.

If nothing else it appears the torque will be good for a 3500lb truck!

[My427stang]

Sure!

My427stang  at cox.net

[TimeWarpF100]

Sure!

My427stang  at cox.net

Tried a few times but keeps bouncing back saying file is too large. Gotta figure out how to make it smaller.
Tried both pdf and JPEG

[TimeWarpF100]

Ross,
For some reason am having a issue sending docs to your email.

I did look up the Compression stuff & remembered the reason for the .100 down. It was to double check my math as the initial comp came out to 9 to 1
(combustion chamber issue)

The real specs are. (fixed it in program)

A few pics

Final chamber size  74.0 cc

Dish volume   18.0 cc

Head gasket 4.400 bore x .041 compressed

Deck height of .012   

With this info is where I came up with the 10.41 to 1

[My427stang]

I replied to your email, looks good to me!

To add some additional thinking to the decision, we had a discussion on Speedtalk a long while ago on whether equal length tubes were beneficial, same with a balanced length intake, and the answer was, yes, no, it depends LOL

You could put the longer primary tubes to match the shorter intake port lengths to balance the peaks a little, whether it would work or not who knows? or, you could optimize each primary tube to its intake port length which would theoretically make a lower peak overall but a flatter torque and hp curve....maybe LOL

Can't really know without testing, but in the end you are in spitting distance of happiness even if you tried to screw it up LOL

You have a well blueprinted motor that seems to match the end use of the truck, now build a set of headers 2 inch with a 3 inch exhaust and good mufflers it should do great things for you.

Thanks for sharing the program information and all your math, it's always good to talk to guys who don't assume the dimensions on the box.  As you can see, no two end up alike unless you make them exactly the same.

How long until you start building your headers and even more, when do you think it'll run?

[TimeWarpF100]

Thanks for all your help & input!

Goal was to start on it May 1st. Health said no.

Latest was August 1st but have another vehicle in shop that cannot be left outside. Yeah is a chevy . . . Just dont tell anyone! (not mine)

My exhaust parts should be here by this coming wednesday. Chevy should be picked up by then (stored here)

Then I can get to where the '66 is stored and bring it to shop to start the header~exhaust. I need to pull the front clip to paint the core support as when I moved did some assembly to help eliminate damage going across the country.

Much easier building the headers with the front clip off.

I can then of course add the fresh show chrome Mercury script covers, add brake lines, LARGER fuel line.
Truck Box~Bed is still off so should make for building rest of exhaust much easier.

I need to finish up a bit of grinding~welding on bed~box then I can prime paint and install.

Need to finish up inside cab wiring, add heater assy but its getting close.

Engine has never been fired. Hope its ok as been sitting done since 2009. Truck has been out of sight but not Quite out of mind .. Some times it will go months before I even go take a look at it. Gotta just block it out that I own it as drives me nuts not being able to finish it up.

I am hoping to have it running by September 1st. Gotta sell more stuff to finish it. Maybe the 416 FE . .

[TimeWarpF100]

Oh Wow!

Ordered the Shoenfeld header parts lunch time on Wednesday. They told me they would be here next wednesday.

Everything showed today, free shipping!

Time to get busy . . .

WIll have to add to the collectors they are 8"

[TimeWarpF100]

Ordered a box of misc mandrel bends in 1 7/8" also.

I will build a set of step headers. Still working on the pipemax program to get me in ballpark on the lengths . . .

Looks like peak HP will be pretty flat around 5200-5800, with peak closer to 5400.

When PipeMax talks about fps on both intake and exhaust how do I convert from Mach? And at what RPM? At the peak HP?

[jayb]

Sorry I'm late to this party; been buried in other stuff.  In a nutshell, I'd stick with the cam you have if you want to power brakes to work reasonably, and I'd probably build a set of 1 7/8" to 2" to 2 1/8" step headers.  Primary pipe length isn't going to be critical; shoot for around 30", but anywhere between 25" and 36" should be fine, and I also wouldn't worry about keeping the tubes all the same length; I think it is more important to get that straight shot out of the port for as long as possible, and then maximize the bend radius of the tubes.  If you can afford a merge collector that would also be a good investment, and a long collector will help you quite a bit; the collector volume is quite a bit more important than the primary pipe length.  If you are going to put mufflers and an exhaust system on the truck (I assume so!) put a crossover pipe at the end of the collectors, to effectively define the collector length.

I think Ross's numbers for HP and torque are probably about right, and bear in mind that a chassis dyno will give you rear wheel HP, while the engine dyno software will give you flywheel HP in most cases.  So don't be disappointed when you get to the chassis dyno and only see 440 HP; that will translate to around 550 HP at the flywheel.

Looking forward to seeing the header pictures and the dyno numbers...

[TimeWarpF100]

Sorry I'm late to this party; been buried in other stuff.  In a nutshell, I'd stick with the cam you have if you want to power brakes to work reasonably, and I'd probably build a set of 1 7/8" to 2" to 2 1/8" step headers.  Primary pipe length isn't going to be critical; shoot for around 30", but anywhere between 25" and 36" should be fine, and I also wouldn't worry about keeping the tubes all the same length; I think it is more important to get that straight shot out of the port for as long as possible, and then maximize the bend radius of the tubes.  If you can afford a merge collector that would also be a good investment, and a long collector will help you quite a bit; the collector volume is quite a bit more important than the primary pipe length.  If you are going to put mufflers and an exhaust system on the truck (I assume so!) put a crossover pipe at the end of the collectors, to effectively define the collector length.

I think Ross's numbers for HP and torque are probably about right, and bear in mind that a chassis dyno will give you rear wheel HP, while the engine dyno software will give you flywheel HP in most cases.  So don't be disappointed when you get to the chassis dyno and only see 440 HP; that will translate to around 550 HP at the flywheel.

Looking forward to seeing the header pictures and the dyno numbers...

Thanks for your input Jay!

I would be happy with 440 at the wheels and 460 or more torque. Although for the $$ spent if thats all it makes would never do it again . .

I was just going by what my mostly stock 427 Comet did.

It made 420hp & 440 tq at the wheels on a 105 deg day with no tuning. Pretty much as I drove it to dyno.

Stock bore 427
Stock unported MR heads
9.6 to 1 comp
6113 Hooker headers
Good 3" exhaust with Dyno Max Ultra Flow mufflers, it did have a crossover.
It had a close to stock solid cam
Stock carbs and MR intake
Stock ignition etc

Again that was with a Top Loader so do expect more loss with the C-6
In the past I have done engine dyno then chassis dyno just to see the loss.

Pretty much all were a 100hp loss with a 4spd and 120 with a c-6  That was 500hp engines.

Looks like my dyno program is a bit HAPPY! 

Its typical cool arizona day 1000' elevation, 72 deg temp with 12% humidity.
Typical for the PHX area

I am at 1966' elevation that by itself kills power around 25hp.

If I change the desktop dyno to 2000' elevation, 100 deg F and 30% humidity it drops the numbers to:

548Hp @ 5400 RPM

586 TQ @ 4200 RPM

It shows 438 RWHP & 469 RWTQ

Which is pretty much in ballpark to what Ross/Jay said

Again its just a bench race tool. The real dyno will give me the numbers . . .

I will be very very disappointed if it does not make 460 TQ to the wheels . . I did a LOT better with a Cast Iron D3 head in my 460 pickup . .

[sumfoo1]

you don't put the plug in for the heads?