John Smith wrote: i am looking at an antique truck. The original engine was replaced with a Chevy 350 crate engine. Otherwise it looks original. Problem is, when you start the engine it sounds like a hot rod -- throaty muscle car type of sound. I want a sedate old car sound. My question -- is this sound simply a funciton of the muffler? Could I tone it down by changing to a different muffler? Or is this engine sound due to the engine, and no muffler is going to change it?
thanks Depends on what you find objectionable about the sound. If it's simply the volume, then yes changing the mufflers will help. However you will have to seek the advice of a GOOD muffler guy as most aftermarket mufflers are aimed at the "performance" crowd who value low backpressure over quietness. Stay away from "turbo" mufflers, glasspacks, and Flowmasters or imitations thereof. They sound good, IMHO, but aren't what you seem to be looking for.
Alternately, you could run a glasspack in series with the existing mufflers, if they're "turbo" style or similar. This will yield a deep, throaty sound without a whole lot of volume. Also adding a balance tube, crossover, H-pipe, whatever you want to call it, will mellow out the sound without any performance hit.
If what you dislike is the lumpy idle due to a performance cam (which crate motor are we talking about, anyway?) there's really not much that can be done short of installing a milder camshaft, which IMHO isn't worth it.
good luck,
nate
From the OP...this is an "antique truck". Can we assume there's little or no sound insulation material around the cab area? When you "start the engine it sounds like a hot rod". Does the sound diminish/go way after startup? Is the sound acceptable after startup? Are there headers or the stock exhaust manifolds? Do you care what it sounds like outside the cab (i.e., what others hear, but not you)?