I remember doing that to my 318 in my 72 Barracuda back in 1983. I thought I was hot **** with that carbon cleaned up, but that poor thing would still barely brake one tire loose. Wish I knew then, what I know now.
It's a very good fix for one with heavy carbon from put putting around town. I've blown out huge chunks of carbon and crap out of one before. It works good in that instance.
