Hey
I have a 78 f-150 with a 400 under the hood and i recently straight piped it, but with the straight pipes i have no snap at all it is just an annoying growly kind of sound. How can i make it snap without putting a pipe or anything like that on it. I am running 2.25 pipe off the manifold should i cut it down for some pressure????

 

Is it a 400m or 351m most trucks ended up with a351m, my opinion is either one of those engines are junk, throw away heads, gutless . they needed back pressure to run write camming seems to help in the 4-speed models but the auto are a different story these c-6 tranny is bullett proof ,if you have cash to throw at it there are things you can do, best bang for your buck in a 460/429 swap.

 

Here's an actual answer for your question.

The way my brother got his 351M to snap on his '78 Bronco was to put a pair of Thrush Turbo Tubes on it. He had headers with a dual exhaust. Basically this muffler looks like a glass pack, but has no glass in it. I think he bought them at Napa. His Bronco snapped so loud that it would set off car alarms in the area. It was LOUD! Not exactly my style, but it was cool. I like the more deep throated sounding exhausts.

BTW, these engines aren't anything special, BUT, properly built they aren't too bad. My brother's was mildly built and woud make more than enough power to get into trouble with! One heck of a truck!