Hey guys quick question,what's the header bolt size on a 70 cutlass?

 

3/8 x 16, 3/4" or 1" long depending on header flange thickness. Longer with stock manifolds, probably 1.25" will work; depends on washer thickness somewhat. Try for 1/2" or so of threads into the head.

 

Good thing is if it is just a little too long they are thru bolts, so you should be ok. I like to use a thick washer like the ones on the center bolts of the dreaded tubular exhaust manifolds whenever it is feasible to spread the force of the bolt.

So, I ended up using 3/8 NC x 1.25" on most all of the bolts.

sb

 

For you guys who've done headers,do you feel thread lock should be used on bolts? And have any of you tried the super seal geader gaskets from mr.gasket? I had those on my transam,but a bolt got loose and the heat disintigrated the gasket because of a tiny gap, what do yo recomemd?

 

I have used, with good results on mopars, lock washers and the Remflex brand of gaskets. On slant sixes I have used the same type of material as remflex for both the manifold gasket and the "hot box" gasket from a company in Oz...but I digress:

http://www.remflex.com/

sb

 

Mr. Gasket Ultra Seals work great.

 

Ditto