Here's the deal;
I've got a 98 F150XL 4.2L 5-speed w/3.08 and 39K on it. Airaid FIPK should be here in about a week. I'd like to get a new exhaust, and have been hearing good things about Flowmaster. I've checked their website, and can't decide between the 50 Delta Flow and the 70 Big Block 2. I'm not thinking about changing the rear end to 3.55, so I have to be careful to keep the backpressure up - can't afford to lose any low end torque. I've read several positive posts about the 50 Delta Flow, but I'd like to know if anyone can tell my why they chose the series 50 over the series 70.
Cheers!

 

I chose the Flowmaster 50 Delta flow based on a lot of posts on here and the fact that it would give me the most performance without too much noise. I also talked to a few muffler shops in my area and got there input. I believe the flowmaster website has information comparing the 2 you mention and that the 50 has better flow than the 70 which is what I wanted, the sound and tone is totally subjective tho... what one person thinks is too loud another will think sounds too quiet... I did use the stock pipe to keep low end and so far I feel no low end lost, but on the top end I am sure it has helped... you can feel it. Hope this helps.

 

I forgot to add that someone on here said there mother approved of the sound... that told me I was safe picking the 50!