Hi I have had grade 5 headbolts on a stock headed flathead. Is stainless steel 7/16" strong enough replacement for this? thanks, TP
Are you looking for "DRESS" or strength?? Grade 8 head bolts/washers OR studs/nuts/washers are available from ARP. (they actually EXCEED Gr 8 strength)
i was @ a car show where a guy's "head bolts" on a flattie was easily recognizeable as the stainless bolts you get off the shelf @ Ace Hardware!
there is a place called industrial bolt, they also sell ARP, I'd like them almost equally for strength and shine. so is that a affirmative or should I just experiment? TP
From what I understand, the original headbolts that Ford supplied, exceeded gr 8. Gr 5 is not much of a bolt IMHO. If you do purchase the much stronger Stainless bolts, The heads of the bolts can be ground clean of any sign of lettering/insignias etc. Then they may be polished to a high gloss shine if desired. Just remember that a bolts threads are designed to pull/stretch Before the threads in the block strip. You will be putting ss threads into a softer block so you will be cir***venting the original design in which the bolt will strip before you wreck your block. But if you adhere to proper torque specs you will be ok... So, Just something to keep in mind... JMHO . . . . moe
I would not use stainless head bolts. Some folks nthink they tend to "gall" the threads in the block also. Go buy a stainless bolt then put a torque wrench on it and see reading when it breaks.
Be careful, the typical stainless bolts you find in the hardware stores are not as strong as a regular carbon steel bolt. ARP makes a stainless Grade 8 bolt, and Totally Stainless probably does too. But ARP doesn't list any head bolts for a flathead in their catalog. Try giving them a call, they are right there in Ventura. Also check out their technical literature and see if it addresses the galling problem that 19Fordy mentioned, anti seize compound might work.
It may also be helpful to find out what process is used to actually make the threads on the stainless bolts you buy. I think "rolled threads" are better than "cut threads". May reduce "galling" factor.
Very good point, I would not use anything but bolts made specifically for replacement of the original flattie bolts. Many of the asian SS bolts have really lousy threads. Other than the "show" factor, SS head bolts offer no advantages and as pointed out can gall.
Although ARP doesn't list head bolts/studs specifically for FLATHEADS in their catalog; Speedway and/or Red's Headers have sets. Both recomend "Permatex Thread Sealant - Part # 14H" as both sealant and anti-sieze compound.
Zibo, They have a wide selection and can offer grade 8 in s/s bolts. That place has pretty much anything you need bolt wise. I been going there for bolt replace on the re-buld of my truck. The guys that work there are preety helpful too. good luck Ken
I used all SS bolts in my flattie. Came from an industrial bolt supply house. I machined the tops smooth so I have no idea now of the markings. I did not want rust on the heads and did not want them rusted to the sides of the holes. I am using alum heads so i figured that the alum would crush before the bolts would break. Been 5 years and no leaks and no rust. I like the look also.
thanks guys for all the info. I am going to try them out, as long as I can get a quality bolt, and let everyone know if they work. Thanks alot! TP Andy, the aluminum has a lighter torque spec, so they should have a higher success rate. do they lose torque after a while?
Cast iron OR aluminum heads should be RE-TORQUED at least three times after ***embly. Between gasket compression and minor fastener stretch, (engine heat/cool cycle) they need to be done a couple of times after the engine has been run for a while. If your going to use studs (with nuts) OR bolts; USE HARDENED WASHERS to protect the surface around the bolt holes. Don't "chinz" on the washers, regular washers will start to "DISH" and chew up aluminum heads.
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