83glx5.0

Are under drive pulleys worth buying? Do they give you any noticeable gains on a stock or modified engine?

AYEOH5.0

for the small gain they are not worth it. can cause charging problems, cooling problems, etc.

86 5.0L

I dont think they are worth the problems they make

83glx5.0

they do look spiffy though with the blue anodized though lol

w8less

just buy a 3in race crank pulley

Jfsram

It really depends on what you consider noticeable, they do free up some power but not an obvious gain.

If you are making alot more heat than stock and your radiator clogged. You may run into cooling problems. Otherwise, no. A perfectly running Mustang swapped over to underdrive pullies will not make it overheat.

As for charging problems. Again no. Here is what you will see. At idle your voltage will drop to about 12 volts. If you have a pile of accessories running at the time, combined that with idling, it will drop even more. With AC, rear window defroster, electric fans cycling and headlights on. It can even drop to about 10 volts. Is this a problem? Not if you are the slightest bit aware of your car and it's situation. Just do not force this scenario for a super long time.

You can upgrade the alternator but I've been driving my Mustang like that for 3 years and have NEVER killed the battery. It's not a nice weather Sunday driver either. Even with snow storms and stuck in bumper to bumper traffic with the AC on. It's been alright.

Another time I like to see underdrives is on a high idling, high rpm race engine. This keeps the accessories from running at warp 9 speeds.

luckythirteen13

put the money towards something else

mendez4047

not worth the money. like said above, spend your money on something else. you wont feel the 8hp