D-450 headers in early a flange question

[Syleng1]

So after 4 months my headers arrived for the 66’ Barracuda and a 273 engine.

Honestly I was disappointed as the welds look like poop. I am a welder by trade so those need to matter.

Anyhow I ordered the flanges welded smaller for the 273 head ports and they arrive with 340-360 ports. They are ceramic coated so I void the warranty if I weld them up myself. Summit does not know what happened and it’s another 4-5 month wait for replacement ones.

Long story short- the sealing surface is now very small. Any advice for making sure this seals outside welding flanges and the warranty is out the window? Almost $1000 for Mexican made quality. Very disappointed for sure.
Syleng1

 

[RustyRatRod]

Some pictures might help us understand. I'm terrible at envisioning something from a description. I had those headers on my 65, but it had a 360 and I was in no way interested in making the ports smaller.

 

[Plymouth 65]

Use the Doug's headers gaskets! I had a leak and replaced one with a regular Felpro exhaust manifold gasket and it leaked worse. 65'

 

[Syleng1]

Some pictures might help us understand. I'm terrible at envisioning something from a description. I had those headers on my 65, but it had a 360 and I was in no way interested in making the ports smaller.

Rusty- the head mounting flange on the header is opened up to a 340-360 port and the factory 273 port is smaller. I cannot show a picture right now but the compressed gasket instead of like 1/4” flange surface is cut down to less than 1/8” due to the size difference. The d-450 headers port sizes are larger than the 273 flange surface so gasket compression is very narrow and I can see issue with leaks down the road. I’ve looked for a all copper or aluminum plate gasket cut for the 273-318 head without air ports would help but welding the flange smaller and machining them flat is the real fix.... or wait 4-5 more months for another set.

 

[RustyRatRod]

Rusty- the head mounting flange on the header is opened up to a 340-360 port and the factory 273 port is smaller. I cannot show a picture right now but the compressed gasket instead of like 1/4” flange surface is cut down to less than 1/8” due to the size difference. The d-450 headers port sizes are larger than the 273 flange surface so gasket compression is very narrow and I can see issue with leaks down the road. I’ve looked for a all copper or aluminum plate gasket cut for the 273-318 head without air ports would help but welding the flange smaller and machining them flat is the real fix.... or wait 4-5 more months for another set.

Yeah I understood that, but lemmie ask you, other than making them the same size, what would that accomplish? A small port into a big port will have no turbulence. As long as it will seal, send it. It'll be fine.

 

[Syleng1]

Yeah I understood that, but lemmie ask you, other than making them the same size, what would that accomplish? A small port into a big port will have no turbulence. As long as it will seal, send it. It'll be fine.

Correct but when I over lay the Doug’s gasket over the 66’ port the crush area is only like 1/8”. Maybe I’m over thinking because unless I have a muffler failure or a banana blocking my tail pipes there should be no back pressure build up to cause what I invision the “weak link” from blowing out.

when the engine was dyno’ed they used 340 extra long tube headers. No leaks but they did like 10 pulls and it was done. You and I are both old enough to know real world stop and go and torque will create a leak if it can. Murphy’s law or something like that lol!

 

[RustyRatRod]

Correct but when I over lay the Doug’s gasket over the 66’ port the crush area is only like 1/8”. Maybe I’m over thinking because unless I have a muffler failure or a banana blocking my tail pipes there should be no back pressure build up to cause what I invision the “weak link” from blowing out.

when the engine was dyno’ed they used 340 extra long tube headers. No leaks but they did like 10 pulls and it was done. You and I are both old enough to know real world stop and go and torque will create a leak if it can. Murphy’s law or something like that lol!

Maybe. Maybe not. I like the Remflex gaskets. I have one on Vixen. Since Freddie opened the exhaust manifold outlet to 2.5", the actual sealing surface is pretty thin. It seals fine.

 

[Syleng1]

 

[Syleng1]

Maybe. Maybe not. I like the Remflex gaskets. I have one on Vixen. Since Freddie opened the exhaust manifold outlet to 2.5", the actual sealing surface is pretty thin. It seals fine.

Thanks.- that’s some info I can use!

 

[RustyRatRod]

View attachment 1715761705 View attachment 1715761704

MadMax that beeotch and stick those out the fenders. LOL