I have a 2000 312 and mine was real easy, just needed flappers for the exhaust. Later I ended up putting on some nice stainless tips and it sounds and looks so much better.

312 1997 Silent Thunder Crack
 

I am doing some work on a friends 1997 312 w,502s.Upon looking I noticed the underside of the silent thunder has a large crack in the glass,about 14" long.Water and exhaust exit it now.He must have run it it for awhile for the crack to grow.It is clean through.How much for a new one or is it worth repairing?

should be an easy fix .....or loose the box ....:drink:

Is the silent thunder box removable from a 1994 382?

I removed mine from my 97 and it sounds fantastic! Someone with a 94 will chime in but I bet is!

Anyone? Looking at a 94 382 this weekend. Definelty have to remove the silent thinder box if I end up buying it, hoping that it is removable on a 1994 382.

382 came out in 95 .... 99% sure it can be removed ......m

My bad, owner has it advertised as a 1994.

I had my box off for a while. Got tired of the noise and complaints after a while, so I put the box back on, but removed the 4 plugs. There is plenty of room to add 4 more holes / plugs allowing more water to escape with plugs out, and improve the sound. I like this sound best. Louder than stock, quieter than wide open exhaust without the crackle. Smooth sound, but very deep and does not irritate my neighbors or when going into marinas in the evening.