10-15 hp from an underdrive pully?

Seems kinda high for a simple bolt on. But hey, since my front end is all apart, im putting one on from BBK. Could be the best 75 bucks i ever spent.

Anyone know if that kinda HP gain is realistic on a LT1?

Expect 7-8 RWHP.

Also, do you daily drive the car?? Remember what an underdrive pulley does....slows down the accessories.

Expect 7-8 RWHP.

Also, do you daily drive the car?? Remember what an underdrive pulley does....slows down the accessories.

its a 94 with 40 thousand miles. Needless to say its not a daily driver.
I heard there is a "constant voltage" alternator that eliminates problems caused by after market pullys. I also heard they cost a fortune--heard anything?

Never looked into it.

If it isn't a daily....don't worry about it.

Mine will be getting a pulley as well, when I finally get around to this swap.

I've been using a March brand power pulley kit for well over a year on my 95 LT-1 daily driver. I put it on at the same time as a cat-back exhaust, and together they made a very noticeable power difference. I originally bought the 2-piece kit which includes the alternator pulley, and I do not recommend that. The alternator pulley hollowed itself out and spun off, ruining the shaft and requiring a new alternator. I have been using the main (crankshaft) March pulley with a stock alternator pulley for a long time with no problems, and I am always stuck in traffic at idle. As long as you have a decent battery you should be ok. This is a pretty easy thing to install and is affordable. I don't know the real HP gains, but they do exist. Hint: do not buy a gear puller for the harmonic balancer, you don't need it for an LT-1. The main power pulley bolts right behind the harmonic balancer with 3 bolts. You may have to buy a new serpentine belt depending on the kit. PS: Anybody want to buy a gear puller, new in box? :banghead: