Howdy everyone -

I spent 2 hours yesterday at the Quantico MCB auto craft center, using one of their parts-washers. I was able to do a great job on everything I put in the tank (2 om603 heads, all the bolts and brackets and stuff of my 87 300TDT, etc, etc) - but the one thing that I could not get clean was the intake and crossover manifolds. They were sooooooo clogged up with this TAR, I had to fight even using a screw driver, still didn't get the job done. I have two sets of these parts, the other set only had soot, no tar. This car was fed WVO for 3 years (before I bought it) - could that have been the source of this gunk?

What do you guys recommend for dissolving this crud? I also have it in the turbo neck (where the crossover pipe connects).