St Upgrade
 

well i am finaaly done with my "thru thunder" i just want to let everyone know my approch to it. I copyed RAM'S idea he did on his 272.

1. bought 4 inch stainless flex pipe (semi exhaust) 10 feet

2. cut them to approx 13 in for the inside pipes and 22 1/2 for outside pipes. took them to a local welding shop to have the square tips made and welded to the ends of the pipes.

3. inside the box mine had a brace that went thru the holes that was wood if you have these u must grind it out first or the pipes will not fit all the way to the end.

4. after a test fit for length you will need to cut slits in the transom ends of the pipe to fit over the thru hulls of the boat which are also 4 inch.

5. i secured mine with 4 inch muffler clamps on the transom side. if you use these clps u will have to cut the hols bigger in the box so when u slide the thing on it fits inside the box. after that draw it up EVENLY with the u bolts and your ready to rock:D

i fired it last night and NO RESONANCE like before. it sounds GREAT for stock SBC i can't wait to get it on the water. i keep forgetting to take the camara and get picks but i hope this will help anyone else who wants to TACKLE this project. i am glad i did it:drink: :drink: :drink:

nice job Biz get up some pics

we need pics, and a sound bite :D

Ramb

here are some pics not the best but you get the idea:D

1 more

Looks good!
So is the box now dry?
Bop over at the Formula forum wants to do it too.

yes the box is dry.

How does it sound in the water?

It sounds much better on plane.
not too loud, but much better. I really liked it.

I have a long video I made of my boat after the mods. if I can crate a short blip, I will post

sold my 272 and the new owner really liked the exhaust mods too.
now my 336 is too quite :D

Ramb

Yup i like it alot.:D

Great ALOT louder at idle on mine. The sound just bounces off the water. :evilb: