Its not the Rubber that's the Problem. The Rubber is bonded to an outer Steel Shell that's pressed into the Eye of the Spring as part of the Bushing. I have purchased a Sawsall to cut 2 Grooves in the Shell and take a small Section out. Should allow the rest of outer Shell to be knocked out with a Punch. The replacement Bushings won't fit with the Shell still in Place. Fairly thick.

  

Actually the cutting method is about it then. Unless you have an air chisel available. I thought you were still fighting the rubber too.

Y's guys rule!
Looking for McCullouch VS57 brackets and parts. Also looking for 28 Chrysler series 72 parts. And early Hemi parts.

MoonShadow, 292 w/McCulloch, 28 Chrysler Roadster, 354 Hemi)
Manchester, New Hampshire

I just did a set of springs like this.  They were out of the car so it was simple.  I had a socket that was just a tad smaller in diameter than the spring.  That along with a good hammer drove them right out.  Put a little grease around the new bushings and reverse to process to put the new ones in.

I also have one of these which has come in extremely handy of the years. I've used it for items such as this, u-joints, ball joints, just about anything.  

https://www.amazon.com/OTC-7249-U-Joint-Anchor-Service/dp/B0002SRGXY?ref_=ast_sto_dp