I have a 360 with two 450 Holley's tunnel ram setup and compression of 11.2:1 I first blew the driver side head gasket, replaced it with a different type gasket and as soon as I fired it up to make sure nothing was leaking it blew the passenger side. The gaskets that blew was the Fel Pro 1008 Ihad a set of Mr Gasket that I put one on the driver side but plan on putting Cometic on both sides. Does anyone have any clue what could have caused the problem; they blew almost straight across from each other. The driver side was leaking about at the #5 cylinder and the passenger is around the #4 cylinder. I had tooling at my work check the driver side head on their flat stone with dykem paste and everything was good with it. I had 93 octane in it at the time the heads are ported J heads.

Did it blow #5 into the lifter valley? I had this problem on my blown 340. The culprit,detonation. Went thru a few sets of pistons and head gaskets. Then I discovered it had too much total timing for my combo. Pulled out 5 degrees. Same gaskets since 1991.
Doug

11.2 with iron heads and pump swill, yeah, that could be a problem. What is you total timing? Have you jetted it at all? It could be very lean as well.

It's leaking antifreeze on the outside of the block, none getting in the oil or oil in the antifreeze. I believe its around 26 degrees at 2500 rpm

did u retorque ur head bolts. i retorque them the next day. loosen one & torque it in sequence. 11-1, pump gas. never had a leak. using the same gasket as u are. some will say that isn't necessary, but i have no leaks. using the same gasket as u are. stay safe, seeya.

Could the problem maybe be with the Flowkooler high volume water pump and and the combination of March Performance pulleys causing too much flow and pressure building up.

you should not have any problems with fel-pro gaskets, to me it sounds like you need a new torque wrench

Check to make sure the timing does not continue to climb w/RPM. Seen this happen w/some distributors, and eat headgaskets. I lock out my distributor's advance.

On the newer blocks the head bolt holes are not blind, they go into the water jacket and need to be sealed.

The clue is the 10 head bolts SUCK. We had the same problem. The gaskets would not fail in the same place twice. The head was flat and the block was decked. I went to the cometics and have had 0 problems since. New video

http://youtu.be/1HtN08OzO0s

Say that to the ford guys.

Maybe if they're going 6.20's with 60psi and 12:1, nawww.

http://www.youtube.com/watch?v=pMK7hOEGWSw

I agree that its likely timing advancing too much. That's what caused problems for me when I stabbed in my new mp distributor and it had 55 degrees advance built in. Why mopar performance sells em like this is beyond me. The felpro should be fine at your level. The cometics are good but believe me they can be a pain to get to seal. So I don't recommend them unless you really need em. And at 11.2 I don't believe its necessary.