Best RTV for exhaust manifolds?

#1
Just got my exhaust manifolds back from machine shop. Wanting to bolt on but wanted to ask what rtv have people used that they can vouch for. I was considering 3 different ones. All permatex. High temp red I think is good for 650 degrees, ultra copper is about 700 and they also have a "muffler sealant" rated for 2000. Anyone ever use these or another product they can recommend? And before anyone tells me to use gaskets, I can't. Motor is a 78 and they don't make any performance gaskets for this motor. Just ones that have a reputation for blowing out which is why I am going gasketless and had manifolds machined.
 
#3
Ultra copper and have the mating surface smooth then use even torque to tighten them down.

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earlbrown

runs with scissors
#11
Use whatever silicone/RTV you have that hasn't solidified yet. It's not going to matter.

The end result comes from the actual application, not what color dye the goop has in it.
 

earlbrown

runs with scissors
#13
If you just have to have colors, get the red. The red dye is rated higher than the copper dye.


Not that it really matters. Anything is better than nothing and the factory didn't use anything.