Well it seems to work pretty good to me. I think the Indy EZ heads were a little to big for my 440. I bought them to go on a 511 stroker build I was going to build. Well that feel through, so I decided to use them on the 440. Also at the time I only had a 9.5 inch 4200 stal converter. Again used what I had at the time. But I used of had a 8 inch 5600 one. Which I ended up installing one but never got to try it out before I sold the car.