[CC69Rat]

Now that I know more about the engine, yes I agree it can handle the 2.5" exhaust and Magnaflows. My previous post, I had assumed a stock 350 with 2.5" exhaust, X Pipe, and MF, .. I wouldn't do 2.5" stock personally. I'd do 2.25" but with a few mods such as what this engine has it's not going to be an issue running 2.5" IMO.

I agree with Matt too, a little tuning might be necessary now that she can breathe a little easier. It may have more power than it ever did before.

http://www.howrah.org/exhaust-system.html

Do you have a local performance machine shop? I'd drop it by there and let them put it on their machine and dial it in just right.

Backpressure is a weird animal. Too much and it will impact performance. Too little and it will impact performance. Once you hit that sweet spot you'll know it.