I may have the worst luck ever with engines.

[John McMahon]

Originally Posted by fastrods

You are not the only with bad luck. I had 2 pond engines, problems with both. The first one had 2 sleeves that would not seat in the block, they sat about .15 too high on the deck, which would have warped the head or caused a leak!
My replacement block started to leak water out of the rear water jacket after about 2 hours of run time. Robert Pond took care of welding it, but I had a lot of work and expense due to this.
There are a lot of good suggestions on here already.
There should be a provision in the top of the studs for an allen wrench. If not, I would remove the studs using 2 nuts, tighten the top nut against the lower nut and then loosen the stud by turning the lower nut. They come out real easy, I know from experience!
If you want to try a sealant first, use Moroso Ceramic Seal, it has been widely used by racers for years in aluminum engines.
http://store.summitracing.com/partde...5&autoview=sku
The builder should have used arp sealant or equivalant on the threads, but they are human. That could be the culprit since you said it is the #8 cylinder and there is a water jacket back there. I do not know how the Shelby block is cast, I doubt the studs go into the water jacket, but that could be possible.
I build my own engines, it is not rocket science and is actually not very difficult.
I know most of the guys on here use builders and that works too, but when things like this happen, it puts you and the builder in an awkward position.
The problem could be his fault or it could be a bad casting or gasket.
I wish my 2 engines were the only bad luck I had!
I can make a pretty long list of broken components that I had to replace on my Kirkham build. If mine was done by a builder, he would have quit after this one!
Good luck!

I have to agree with fastrods, I used the Moroso product on my Mustang racer for some coolant leaks and it worked great. This may help eliminate the minor leak issue with coolant before going into a full teardown.