So my 67 Bird has leaky Headman headers PO installed on a 75 400. I was thinking about swapping out the headers for some stock manifolds. Will the 75 firebird manifolds fit ? They look like they might but would like to know for sure. Also thoughts on LBM besides they're expensive as hell. Are there any other issues with LBM's besides the oi filter adapter?

They're heavy as hell. But other than that they work very well. There's also some shorty headers made by Sanderson that are supposed to work pretty well too. Nothing is going to be cheap though except stock logs

I prefer headers. Never had any problems with Hedman 35270 headers. My last 1st gen had old Hedman 3-tubes. No leaks. You can go online & find lots of helpful hints on how to keep headers from leaking. My Pontiac friend who did lots of dirt track racing recently told me that he glued 2 gaskets together with high temp silicone, and also used it around each port, on both sides of the gaskets. With the price of gaskets today, it would be cheaper to buy thick gaskets, rather than 2 sets of gaskets.

https://shop.advanceautoparts.com/p...-gasket-maker-3-oz-81878-82160/7160075-P

I think most cheaper gaskets are 1/16" thick. Here are some 1/8" thick gaskets. And there are all sorts of higher priced brands.

https://www.amazon.com/Spectre-Performance-453-Exhaust-Gasket/dp/B001FJD1BA

Some say that Remflex gaskets seal better than anything else.

https://www.summitracing.com/parts/rfl-12-001/overview/make/pontiac

https://www.amazon.com/Remflex-12-001-Exhaust-Gasket-Pontiac/dp/B000TLH3AA

The 3-tubes fit real good. They're not too much over $200, unless you insist on coated headers. The Long Branch manifolds ain't cheap either.

The 3-tube headers are said to flow just as much as Ram Air manifolds.

https://www.ebay.com/itm/Hedman-Hedders-28140-Exhaust-Header/133009958607?fits=Make%3APontiac&epid=194823451&hash=item1ef802e6cf:g:YosAAOSw2EJcopvH

OK, the link don't work on this site. They're $217 shipped from the Ebay seller US Parts Outlet.

Depending upon what you are trying to do with the car I would go log manifolds or the long branch(but I like stock appearing). Since you don't have the original drivetrain whatever you do won't really affect value so do what fits in your budget and what you like.

Looking at the stock exhaust manifolds pictured at Frank's Pontiac parts: https://www.frankspontiacparts.com/engineparts/pontiacengineparts.htm

It looks like the exit on at least one side of the '75 manifolds is in a different location which might cause an issue. So, fit of the '75s may be an issue in a First Gen and should be checked.

Ok, I have Hooker headers on my 69 LeMans and the bolts are a real bear to deal with. I haven't tried Hedmans yet, I hope they're better. That's mainly why I was leaning towards stock. Does anyone have a pic of the 56 manifolds? This is what mine look like.

** need pic of 67 manifols**

I Have used both Hooker & Hedman. My experience with the Hookers was just like yours. I had to modify a 7/16 open end wrench, by grinding it down real thin, to turn one of the bolts.

If you look closely at the pics of the Hedmans you can see that all the bolts appear to be fairly easy to get to. I recently took some 3-tubes off my '68 Bird & put 'em on my '80 Bird. No problem at all. And I'm 70 years old. The 3-tubes are the easiest to install/remove Pontiac headers I've ever used. But, I never had any problems with the 35270 4-tubes either. Used them on quite a few Birds, including several race cars, where I had to install/remove 'em several times, over a several year period. Never any problem.

Summit will sometimes meet or beat the best legitimate shipped price you can find. They definitely don't have the lowest price on the 3-tubes.

https://www.summitracing.com/parts/...7xyQGHbVz6_eGf2Z5nDAVslw8_kaAq3zEALw_wcB

https://www.summitracing.com/parts/...j29jqmaNOvn9wSJeT32UpE98GHEaAjYPEALw_wcB

https://www.amazon.com/Hedman-35270-HUSLER-Street-Hedders/dp/B000CO9BWM

Concerning price, Summit, Jegs, & Amazon Prime now charge tax. Some Ebay & Amazon sellers, as well as some other online sellers do NOT. This can make a seemingly "best" price, not the actual best price.

Yes, the 3 tubes look much more manageable. Can I install them without lifting the engine?

I Have used both Hooker & Hedman. My experience with the Hookers was just like yours. I had to modify a 7/16 open end wrench, by grinding it down real thin, to turn one of the bolts.

If you look closely at the pics of the Hedmans you can see that all the bolts appear to be fairly easy to get to. I recently took some 3-tubes off my '68 Bird & put 'em on my '80 Bird. No problem at all. And I'm 70 years old. The 3-tubes are the easiest to install/remove Pontiac headers I've ever used. But, I never had any problems with the 35270 4-tubes either. Used them on quite a few Birds, including several race cars, where I had to install/remove 'em several times, over a several year period. Never any problem.

Summit will sometimes meet or beat the best legitimate shipped price you can find. They definitely don't have the lowest price on the 3-tubes.

Yes, the 3 tubes look much more manageable. Can I install them without lifting the engine?

Sorry Oldskool, have trouble with the Quote button.
Yes, the 3 tubes look much more manageable. Can I install them without lifting the engine? Thanks

Yes. I removed them from my '68 with the engine bolted to the mounts, and I installed them in my '80 Bird with the engine bolted to the mounts.

Same goes for the 35270 4-tubes. Engine does not have to be raised.

You just have to have it jacked up high enuff off the floor, since they must be stabbed from the bottom. I did it with just a floor jack & jack stands.

And obviously, the starter will have to be off, and the oil filter & mount will have to be off, on the other side.

You can get to some of the bolts from the bottom & some from the top. Some with a rachet/extension/socket, and some with an open end/box end wrench.

At the suggestion of some on some of the Pontiac forums, I made some stands out of wood, to put under the front tires. So, I replaced the jack stands with the wooden stands. I think some call 'em "cribs".

https://www.garagejournal.com/forum/showthread.php?t=321263

That's a nice set up. I'll try replacing the gaskets first .. I had a lot of trouble with the Hooker headers in my LeMans. The Hedmans do look friendlier. Hopefully the bird will be easier.

Go to the link I provided.

Don't like the fit of these Hedmans. I can barely get a matchbook between the pipe and the steering gear. Do the three tube headers fit any better?

That don't look like the 35270 Hedman headers to me. The pipes coming off #3 & #5 exhaust ports come almost straight down. The pipe in your pic is going horizontal.

Check out the pics of the center pipes, and see if that's how your headers look.

https://www.summitracing.com/parts/...XtV5va1f36Xa2uehSCjr0ZuMT54aAu-MEALw_wcB

https://www.classicindustries.com/p...Ca44N4_yrZYG3aQDCBT5RZ2KUwgaAmM7EALw_wcB

Below is a pic of some 3-tubes on my last '68 Bird.

Sorry for the terrible pic. It turns out I do have the Headman tri tubes. Looks like you have a manual steering gear? Is it as close to the header as mine? I would also like to ask what type/brand of gaskets anyone is using? Are the tri tube gaskets the same?

Mine is power steering. I'm concerned it mat be too close to the gear and cause issues.

'67-'68 Firebird Exhaust Manifolds