If you have close ports to the bore, you could try using a solid copper head gasket, not a paper one. I've done that before when the paper/ring ones blow due to too much compression. Just an alternative to go THE BIG 351!
You will have to make it yourself though, but if you are doing the wrenching you can do it.

 

Here is a video how Kevin Millyard, maker of the Kawasaki Z1 six cylinder, made his copper head gaskets.

click here