Does any one have a daily driver with a 408 in it? If so how is it, and how is gas milage? Also would i need to open up my combustion chamber on my stock 5.7L heads.

 

well I don't know if this is what you want but their are a couple of guys inthe truck forum the have 408 and love them. their using theirs with FI. You would need to open those heads up a whol lot to flow enough for that engine. most people are running atleast a stage 2 head on even the mild 408. the top dogs using nitrous on their 408 have been testing the afr 225 head with them.

 

Gas mileage shouldn't be affected for than a few mpg. You should get some ported LQ9 heads. You'd really have to port the hell out of the stock 5.7s to get enough flow. With what a 408 will cost you why worry about gas?

 

I daily drive a 408 with a TREX cam, and the gas milage sucks *** thanks to surging like a crazy bitch and being unable to use 6'th gear in city, I don't have 4.10's either which is some of my problem.