'70 Charger 440 exhaust manifolds, gasket or no?

[OrangeCrush]

I'm resealing and changing gaskets on my 1970 440 Charger R/T to fix some oil leaks and will be removing the exhaust manifolds. My question is: do i need to use exhaust manifold gaskets or not? The Dodge manual states that no gasket is required. I don't have much experience working on old Mopars and wonder what the concensus is on this. Thanks in advance!

 

[Plyrr471]

I just put my oem exhaust manifolds on, replacing headers. I used gaskets, can’t hurt. Don’t forget to use thread sealant on the studs.

 

[1 Wild R/T]

No gasket... Gaskets blow out creating leaks...

 

[Kern Dog]

I’ve wondered why those gaskets are included in every full gasket set. I have used them a couple of times but have also had leaks. I thought the leaks were from the manifolds being warped but maybe it was the gaskets failing all along.
My three big block engines have headers but I have one 360 in a car with manifolds that has leaks. Maybe I should try them without gaskets to see if it seals okay without them. I was of the mind that they can’t hurt but maybe they just increase the chance of leaks ?
It is an interesting point.

 

[1 Wild R/T]

Factory didn't use gaskets, manifolds do warp but typically you get a minor tick, try snugging the bolts while it's hot, sometimes it helps... If not often carbon will build up and stop the leak.... Using gaskets the gasket burns out & you get a big leak that sounds like ****..

 

[pnora]

I’ve wondered why those gaskets are included in every full gasket set. I have used them a couple of times but have also had leaks. I thought the leaks were from the manifolds being warped but maybe it was the gaskets failing all along.
My three big block engines have headers but I have one 360 in a car with manifolds that has leaks. Maybe I should try them without gaskets to see if it seals okay without them. I was of the mind that they can’t hurt but maybe they just increase the chance of leaks ?
It is an interesting point.

Most all the time no gaskets. If the surface on head or manifold is questionable a light film of ultra copper on a clean dry surface can seal up minor imperfections.

 

[Jerry Hall]

If the manifolds are questionable, I have them surfaced. When I take the manifolds off, I make note if there were gaskets on them. If no gaskets, I inspect them and if no issues I reinstall them without gaskets.

 

[Hilljack68]

Does the same policy apply to headers as well? ...or do they seal better with gaskets?

 

[Don Frelier]

Does the same policy apply to headers as well? ...or do they seal better with gaskets?

Headers always require gaskets.
Cheap headers always leak after some use.
Probably the biggest problem with headers

 

[OrangeCrush]

Thanks for the input, there's no gaskets currently and no leaks, I'll keep it this way. The factory torque spec is 30 ft/lbs which seems low but one has to think there's some engineering in sealing two parts that expand when heated. The manifold bolts came out easy and didn't strip which was nice!

 

[Don Frelier]

Thanks for the input, there's no gaskets currently and no leaks, I'll keep it this way. The factory torque spec is 30 ft/lbs which seems low but one has to think there's some engineering in sealing two parts that expand when heated. The manifold bolts came out easy and didn't strip which was nice!

Perhaps you meant nuts and not bolts?
Studs are used on the heads.

 

[pnora]

Headers always require gaskets.
Cheap headers always leak after some use.
Probably the biggest problem with headers

I never used gaskets on my race motors headers. Bead of high heat ultra copper, snug the bolts, let cure 24 hours and torque. Never a leak.

 

[WileE]

Factory didn't use gaskets, manifolds do warp but typically you get a minor tick, try snugging the bolts while it's hot, sometimes it helps... If not often carbon will build up and stop the leak.... Using gaskets the gasket burns out & you get a big leak that sounds like ****..

^

 

[1968rt]

If the faces on the manifolds are clean and flat I use a VERY thin coat of high heat silicone. works great, years of use.

 

[Cranky]

Does the same policy apply to headers as well? ...or do they seal better with gaskets?

The biggest problem with headers is that the flanges are usually not flat and especially so with the cheap ones so a large file is needed to get them to get them that way.

 

[haywire 440]

This was discussed on forcbodiesonly a while back and similar to here many long time members said no gasket. It was also pointed out that having the manifolds surface ground is important.