I need a couple exhaust manifold bolts. 1 for a 390 and one for a 429

[speach]

I am not sure if the bolts are all the same sizes for the 390 and the 429. If so please let me know. Also I am thinking that there may be to different sizes on the two different motors. Thanks for any help. Used is no problem, just not cracked or broken obviously.

[brian faull clc#25881]

I should have 390 manifold bolts. If you still need some let me know. Thanks, Brian. 412 952 6027.

[Joe G 12138]

Recently did a 429. Most any Ace or True Value hardware store stocks 7/16 NC (coarse thread) by 2-1/2" long in grade 8. Buy a nut to screw on exposing 1/4'. Saw or grind off that 1/4". Unscrew nut to clean out threads. Finish file or grind if necessary. If you can get the bolts in 2-1/4" it will save some work, but the 2-1/2 ones are readilly availible and a lot better than using old ones.

Joe Gibeault

[Classic]

Fastenal has them.  You can order online or have your local Fastenal store order them in (not usually stocked).
http://www.fastenal.com/web/products/detail.ex?sku=0137821
Under $1 apiece, but you might have to pay extra for shipping.

[speach]

Thanks guys. I will give you a call brian about those 390 bolts. I don't really want to do studs, and have to grind down anything. I actually have a Fastenal rep that lives down the street from me in my neighborhood. Are the ones from fastenal flared? Does anyone know if the 390 had multiple sizes on the 1 motor? Also I still have not heard if anyone knows if the 390 shares the same bolts with the 429.

[Bob Hoffmann CLC#96]

William,
I took the time to look up the info & give you some answers weeks ago when you first asked the question. You never responded.
Bob

[speach]

Thanks Bob. I did see. Sorry for not responding. I bought a bolt size that you said but I want to get a couple originals to match them. The ones I bought are much bigger than the 472/500 bolts. Wasn't sure if this was correct, and I need to know if the 390 and 429 bolts are indeed the same. I also have not found out if the motors have two different length bolts on them.

William

[Classic]

If by "flared" you mean "flange head", Fastenal has those also (but more expensive).

See:  http://www.fastenal.com/web/products/detail.ex?sku=19949

[TJ Hopland]

Im not sure that the original bolts were that hard.   I suspect they may have been softer to allow for expansion.  One time I did a swap and needed bolts so I just went to the hardware store and got some 8's.  As noted the hardware stores usually only have them in 1/2" steps so you would have to cut to get the correct length.  On one side I cut them but got lazy on the other side and just stacked a bunch of lock washers.   I constantly had issues with the short side.  Gaskets would burn out, bolts would come loose.  Other side with the stack of washers was fine.

They break off easy and are not that hard to drill which also points away from grade 8. 

[speach]

Yea i have seen stainless that are not grade 8 for sale before and was curious about that. I have 8's on my 68's 472 and things are lookin good on that motor.