1 7/8 inch headers

Max Headroom

Master Mechanic
Sep 8, 2011
369
63
Exhaust manifolds can easily get literally glowing red hot... Much much hotter than 400 degrees, I think regular powder coating would burn right off an exhaust header or manifold. Or do they sell a special high temperature powder coating?

I saw a magazine test of ceramic coated vs. raw steel headers where their only concern was how hot they got according to an infrared thermometer during a Dyno run, they were each measured immediately after the pull was made, then again with a 1 minute cool down. The raw steel hit almost 900 degrees and had cooled down to around 500 after one minute, coated hit just a few degrees below 300 and cooled to less than 200 a minute later. However the internal heat of the pipes I'm sure was wicked hot, the ceramic just insulates the pipes basically.

My brother in law had a big block vette where the headers used to glow cherry red. I run sbc made for torque and don't think I make that I make that much heat. I am trying to find out how hot the powder coat can get without damage. I will post whatever I find out. However, I have a set of old headers that I'm going to try it on anyway. I'll post how that goes too.
 
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scoti

G-Body Guru
Supporting Member
Sep 5, 2019
814
93
Texas
My basically stock BBC in my dually has port temps (between port & 1st bend) of around 700° on the ceramic/titanium coated header. Powder coating will not survive. It will need a coating that withstands extreme heat. Manifolds will be more forgiving on temps w/the thicker material but I'd bet PC wouldn't last on them either.

I got the ram-horns for my 64 C10 coated in the same stuff as my duallys cheap, C-list bought 1 3/4" car headers (headers were $50..... Coating was $250). Collectors are showing some rust color but that's the area that sees the most environmental impact & was expected. I've been debating on yanking them (>5yrs later) for a re-coat.
 
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Pc3

Master Mechanic
Nov 17, 2019
334
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06468
And as for that, yeah I was already thinking if the 1 3/4 opening is still slightly undersize I can go at it with a die grinder a little bit to open it up. The opening on that 1 5/8 set is hopelessly small, if you opened up the flange enough that it wouldn't interfere with the port opening you'd be through the pipe.
there you go....
reread post 26..
AHR has what you need but BIG $$there was a set on here awhile back sold for 800 IIRC
 
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lilbowtie

Comic Book Super Hero
Jan 7, 2006
3,462
113
Canton Mi
I'm a little worried the engine is a bit much for the street like you said. I hope it's not lazy and weak in the lower to mid RPM's and just a screamer. I'm seeing similarly put together 406's in the range of 530-580 horsepower. The cam is really the only unknown with the engine, it's a big solid flat tappet, but I have yet to pull the timing cover and sprocket to find out what exactly it is.

Big cam, 3.42's, 26-28 stall, hope you have compression, large runner heads (I wish I had) is not going to be good for bottom end
 

kornball426

Royal Smart Person
Thread starter
May 29, 2009
1,456
83
Philadelphia, PA.
Big cam, 3.42's, 26-28 stall, hope you have compression, large runner heads (I wish I had) is not going to be good for bottom end

Supposedly 10.5:1, I'll probably call around to hughes/tci/ati, etc. and get converter suggestions but it's not a drag car, I'll probably literally never take it to the track so if it doesn't launch hard it doesn't matter to me. If the cam is too radical I'll change it to something more streetable, I'd rather have a hydraulic roller, but I want to find out how radical the cam actually is before I go off ordering an expensive roller retrofit cam.

It was in a street driven car before I got my hands on it, however it was in front of a four speed manual which would be more forgiving of a radical cam. But it has an 850 holley vacuum carb on it so I'm assuming it wasn't too crazy or it would probably would have a double pump carb. I don't know, it's all speculation till I find out what the cam specs actually are.
 

bracketchev1221

Royal Smart Person
Jan 18, 2018
1,005
113
Supposedly 10.5:1, I'll probably call around to hughes/tci/ati, etc. and get converter suggestions but it's not a drag car, I'll probably literally never take it to the track so if it doesn't launch hard it doesn't matter to me. If the cam is too radical I'll change it to something more streetable, I'd rather have a hydraulic roller, but I want to find out how radical the cam actually is before I go off ordering an expensive roller retrofit cam.

It was in a street driven car before I got my hands on it, however it was in front of a four speed manual which would be more forgiving of a radical cam. But it has an 850 holley vacuum carb on it so I'm assuming it wasn't too crazy or it would probably would have a double pump carb. I don't know, it's all speculation till I find out what the cam specs actually are.
A good converter can drive around and still not really be noticeable. We had a 4500 stall ati converter in my friends car and he drove it all over. Granted it had 4.56’s which help to not load the converter and make it want to slip as a 3.42 would. But it didn’t just slip constantly. He ran 11.50’s with a 355 in a street car.
 
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kornball426

Royal Smart Person
Thread starter
May 29, 2009
1,456
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Philadelphia, PA.
A good converter can drive around and still not really be noticeable. We had a 4500 stall ati converter in my friends car and he drove it all over. Granted it had 4.56’s which help to not load the converter and make it want to slip as a 3.42 would. But it didn’t just slip constantly. He ran 11.50’s with a 355 in a street car.

I had a 3500ish stall converter with 4:10's in my 74 firebird behind a pretty warm 355 like ten years ago... And it was absolutely terrible to drive, it felt like the motor was just screaming and barely moved till you were really in it. Maybe there was something wrong with it but I thought that's just how it is.
 

565bbchevy

Geezer
Aug 8, 2011
8,448
113
Michigan
I had a 3500ish stall converter with 4:10's in my 74 firebird behind a pretty warm 355 like ten years ago... And it was absolutely terrible to drive, it felt like the motor was just screaming and barely moved till you were really in it. Maybe there was something wrong with it but I thought that's just how it is.
I consider my Monte's 565 BBC very streetable with a 4,000 convertor, 4.10 gear, 1250 Dominator and 4.50" exhaust but I wouldn't call it practical but my Regal's 355 set up falls more under that category having overdrive and still has the stock gear.
It sounds like maybe you had too much convertor behind your 355 or something else was wrong with it.
 
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kornball426

Royal Smart Person
Thread starter
May 29, 2009
1,456
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Philadelphia, PA.
I consider my Monte's 565 BBC very streetable with a 4,000 convertor, 4.10 gear, 1250 Dominator and 4.50" exhaust but I wouldn't call it practical but my Regal's 355 set up falls more under that category having overdrive and still has the stock gear.
It sounds like maybe you had too much convertor behind your 355 or something else was wrong with it.

Well I remember it had a .030 350 block, a tad over 10.5 comp with edelbrock performer RPM aluminum heads, an RPM air gap intake, holley 750 double pumper, (can't remember what cam was in it, it was lunati but specs I couldn't tell ya), Hooker super comp 2nd gen F body headers, and a built TH350 full manual valve body (which was totally unnecessary and made the car shitty to drive), an approximately 3500 rpm stall converter, 4.10 rear, and 275/55r15 tires in the back on weld draglites all around, I think the fronts were 26/6/15's. Was a pretty bare bones car, had no power options at all, no audio equipment whatsoever, no carpet, no sound deadening. Couldn't have weighed that much... But the thing just didn't want to go unless you buried the skinny pedal. When you got it revved up it was very fast... But it was not fun to drive in the street. I thought the converter had a lot to do with it.
 

bracketchev1221

Royal Smart Person
Jan 18, 2018
1,005
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Well I remember it had a .030 350 block, a tad over 10.5 comp with edelbrock performer RPM aluminum heads, an RPM air gap intake, holley 750 double pumper, (can't remember what cam was in it, it was lunati but specs I couldn't tell ya), Hooker super comp 2nd gen F body headers, and a built TH350 full manual valve body (which was totally unnecessary and made the car shitty to drive), an approximately 3500 rpm stall converter, 4.10 rear, and 275/55r15 tires in the back on weld draglites all around, I think the fronts were 26/6/15's. Was a pretty bare bones car, had no power options at all, no audio equipment whatsoever, no carpet, no sound deadening. Couldn't have weighed that much... But the thing just didn't want to go unless you buried the skinny pedal. When you got it revved up it was very fast... But it was not fun to drive in the street. I thought the converter had a lot to do with it.
Like was said, bad converters will do that. There are 2 different types of converters. Ones that drive "well" at all rpms and those that slip like crazy down low and still function after stall point. Most Cheap shelf converters fall in to the second band. More expensive custom built converters will be tailored to work in the first band. Now granted, an expensive converter is NOT going to be like a 1500 stall stock converter. But the engine is not going to rev high and the car just start creeping away slow either. I had a 5600 stall converter in my Chevelle, and when I put it in gear the rear shocked and the car started rolling. The car drove around the pits just like any other car.
 
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