yet another exhaust question

[85burbanator]

my wheeler is an 88 chevy with tbi, around here there is lots of standing water and stuff you have to go through to get to the trails. i plan on doing dual stacks just incase i stall in one of the puddles i dont want the water to get up into the pipes. i just cant decide if i want to go with 3 inch tube or 2.50 inch tube. hedman makes a glass pack tha is 2.5 inlet and 3 inch outlet that i was thinking of running and just putting a flapper on each stack to keep rain water out. the exhaust is going to be relatively short n it still hs the 350 in it. sound doesnt matter i just need a muffler to be legal in the state parks

 

[neverendingproject]

If your worried about it, just put a turn down on your exhaust that you have. When I had a 305, i got some places where water got into my duals that are hanging strait out, just rev up the motor, and everything goes >>>>> out the tail pipe. I would be more worried about stuff getting in from the top with stacks.

How many people have you seen with water up to theier hoods and as long as they didnt get water in the air cleaner, started right up after they got out?

 

[trailblazr81]

I wouldnt be too worried about water getting up in the motor. But hell ya man... 3" stacks!! Put the flapper on 'em, and chrome 'em. Would be cool if ya had a diesel so they could blow black smoke. Make sure you get a air horn with the pull rope on the roof.

 

[85burbanator]

ive seen a few people(myself included) that have had trouble after stalling with the exhaust under water. granted it doesnt happen often but it happens. also when i stall its usually becuase im bouncing around and the motor isnt getting fuel so i can restart but it sucks when th exhaust is full of water and mud. im just wondering if dual 3 inch pipes is to much for a stock 350 or if i should do dual 2.5 to the mufflers then 3 inches out of the muffler with the flappers.

 

[trailblazr81]

Well if its a stock 350 2 1/4 would be the way, but 3" will look better. And there are so many conflicting reports on the whole thing. 3" is too big and should only be used for 450 HP or more and others say it doesnt matter what size after the headers as long as its not too small. 3" will give a deaper tone. I ran 3" on an old Nova and want to put 3" on my truck tho I will need to get different headers and do some work to the crossmember to fit it.
I ran 3" on a 305... it just sounded better. Theres 3" exhaust kits for 5.0 Mustang's and other cars that dont need it. You could do 2.5" under the truck but have all the visible pipe (stacks) 3". Also Flowmasters, and some other mufflers are all the same inside. Just have different sized inlets/outlets to match your pipe.

You plan on running the stacks outside or inside the bed?

 

[85burbanator]

inside the bed. i plan on them coming off the headers striaght back then up through the bed, attaching the muffler (prolly a round one about 24" long) ill have to use something to go from the smaller tube to the larger muffler since the muffler i want only had 3"inlet/outlet. just use header reducers or somthing, flowmaster has cone reducers from 3" to 2.5 for around 22 bucks a pair.

 

[trailblazr81]

Just do it all 3" then. You could loose a little low end torque but I wouldnt worry about it. Your only talking 1-2 ft of smaller pipe before going to 3."