Ok, I think everyone would agree that 6.0 is about the biggest this blower can handle. A radix just isn't a good match for a 408. My question is:

If a camshaft helps a radix combo, wouldn't ported or better cylinder heads help also?

I'm at 190,000 miles and am replacing my motor with a 38,000 mile LQ9. I want to put better rod bolts in it and a better cam. I really want to get this truck in the 11's bad.

In my my mind porting the heads would help this cause, but some say no. So, if a cam helps, why wouldn't a ported cylinder head help?

 

I say yes it will help. You need to get the air in and out, and the best way to do that is with better flowing heads. When I had my Radix, I had my ported heads. I think the actual limiting factor for the system is the heat exchanger under the supercharger. It is just too small to efficiently cool down the air flowing through it from the amount of power I wanted. Even though I feel the heads would help, I dont think it is necessary to reach your goals. I know Roger ran in the 11's with stock heads on a 5.3 in his truck with a Maggie, and I assume there were others. I would pass on the rod bolts. I have never heard of a stock rod bolt breaking. I changed mine with Katech bolts, and now I feel it was a waste of money.

 

The lower the boost, the more efficient roots blowers are. Anyrhing you can do to improve airflow will help a blower.