All very true and informative stuff. I work with SS pretty much exclusively in my industry and the standard 300 series bolts are not very good when holding power is needed. Since the Gil manifolds are supposed to be torgued to no more than 25 ft/lbs (I think), I havent had any issues with them. If I need something stronger I make them out of 17-4 and heat treat them. For engine mounts (through stringers or to the block) always use grade 5 bolts. I have seen SS bolts break off and drop engines in the bilge. Everyone should check there engine mounts because lots of maunfacturers and riggers use ss bolts for this and they will break or shear. Also dont use ss for any brackets that attach accesories to the block.

I'm not trying to dispute anyones word, but back 30 yrs ago when I was in the fastener business, threads were rolled on mass produced bolts. Cutting would be slow, wastefull and messy. Although technology changes over the years and maybe that is what they do now. However,I'm not sure we are helping Audiofin with making his decision on which bolts to use.

Since when was it the purpose of the board to help anyone? I've always figured the best use of a message board was to confuse people with a bunch of miscellaneous technical ramblings by people that only think they're qualified to go on and on about stuff they know nothing about. Like me.

Hey Blue - you win!

But guess what, my header bolts are carbon steel...

...and my oil is...

Oh Crap!....?

All my bolts (engine mounts included) are SS. They are ARP SS though. I think these are much better than the garden variety alloy found in hardware stores. They hold all my accessories and manifolds in place without a problem (oil pan too!). Good thoughts about the motor mounts though. I do have the garden variety on the rear of the bell housing. Need to probably change those.

I have used SS bolts on all of my accesories, pulleys, intakes and exhaust on a number marine engines and have never had a problem. Although on things such as motor mounts I have stuck to the grade 8 bolts.
One question I do have is should you use lock washers or flat washers on the bolts that secure the coupler to the flywheel?