Eighteen Year Old VOE Mufflers
Every now and then I get to brag about my Vacuum Operated Exhaust (VOE) mufflers I built (and am still building). I just got done with six pair for Pontiacs and I test them on my '69 340 Barracuda 340-S. While my set was off for testing these others, I shot a few photos of them to share.
These use a 4" diameter vacuum actuator, originally found on GM heat and AC systems. With an actuator this big, you can generate a lot of puling force, which allows you to use a strong spring to hold the muffler closed internally. They start to open at around 6" inches of mercury vacuum and are fully open by about 9.
These are made from 304 st. st. so they do not discolor too much .
The original 340 muffler has an 18" long body and they are 21.625" overall length, 2.25" in and out. These I built have a 19" body and they are about 22.5" overall length.
Sadly, they are not terribly high flowing, in fact, they flow about as bad as the typical old chambered mufflers most mustangs had on them. They do better than stock 340 versions but these are 2.5" in and out. However, they are very quiet when closed and very loud when open: as loud as the chambered mufflers but as quiet as the noise reduction systems the '70 340 Dusters used.
Every now and then I get to brag about my Vacuum Operated Exhaust (VOE) mufflers I built (and am still building). I just got done with six pair for Pontiacs and I test them on my '69 340 Barracuda 340-S. While my set was off for testing these others, I shot a few photos of them to share.
These use a 4" diameter vacuum actuator, originally found on GM heat and AC systems. With an actuator this big, you can generate a lot of puling force, which allows you to use a strong spring to hold the muffler closed internally. They start to open at around 6" inches of mercury vacuum and are fully open by about 9.
These are made from 304 st. st. so they do not discolor too much .
The original 340 muffler has an 18" long body and they are 21.625" overall length, 2.25" in and out. These I built have a 19" body and they are about 22.5" overall length.
Sadly, they are not terribly high flowing, in fact, they flow about as bad as the typical old chambered mufflers most mustangs had on them. They do better than stock 340 versions but these are 2.5" in and out. However, they are very quiet when closed and very loud when open: as loud as the chambered mufflers but as quiet as the noise reduction systems the '70 340 Dusters used.
