What Size/Style Header Bolts? and What Sealant for the Studs?

[getslideways]

I am slapping some headers on my 70challenger with a 318.  My question is this, what size bolts should I get? I have read both 3/4 inch and 1 inch lengths, and to get grade 8 hardware from a fastener shop like Tacoma Screw.  Which length is preferred, my header flange is a smidge over a 1/4"? Also is there a special style bolt i should be considering, or is a simple hex head bolt the way to go? and it is best to keep the two end studs and not use any washers of any kind (regular or lock) correct?

2nd issue, one of the front studs was sheered off, so i replaced it with one from a spare head, but i forgot to seal it (since it goes into the water jacket i dont want it leaking), so was going to pull it out and seal it up and reinstall it.  What is best to seal it with.  I have heard some people say Teflon tape, is just ordinary plumbing Teflon tape going to cut it?  Or is everyone referring to something else.

thanks!

[Chryco Psycho]

assuming the bolts do not bottom out I would use 3/4 " long bolts . Header bolts have a smaller head for better clearance near the header tubes .
 Use white pipe thread sealer to seal the stud

[72cudamaan]

Did your headers come with bolts? At a 1/4 inch those flanges are pretty thin,
you might have to go with copper header gaskets if you keep blowing the fiber ones out.
And pipe thread sealer is easier to use than the tape.

[getslideways]

No the headers did not come with any bolts since they were purchased used, thats why i was trying to find out what the best way to approach this is.  Is there a better/easier/available bolt to use than just a grade 8 hardware bolt from a hardware/fastener shop?

[mojavered]

You can go to carquest, autozone, and I am sure there are others.  They sell header bolts.  There are 12 in the pack, about 8 bucks or so.

[getslideways]

Thanks for the tip! does anyone know off the top of their head what the thread size is for the header bolts? thanks!

[getslideways]

smallblocks take the 5/16" header bolts not the 3/8" right?

[Chryco Psycho]

5/16 coarse thread

[getslideways]

thanks!! it was tough finding someone locally that had 5/16 header bolts in stock! everyone had the 3/8th size!