Exhaust system for 402 SWB?

[71CHEVYSHORTBED402]

My exhaust guy is paying the truck a visit tomorrow. My guess is he's going to have to customize this, but he wants me to look into a kit perhaps, and mufflers. I'm using the original manifolds, and hope to hang the system by the original mounts.

1. I'm working with a 402/400th SWB that's primarily original. However a 4/2.5 drop if it matters. Also if it matters, the odd duck has leaf springs, the was built on a frame

2. I'd like mufflers similar original, though if I had to choose among others, a deeper slow grumble sounds awfully nice too. Cost doesn't matter at this point, she's a money pit. I just want her to breathe right and sound good.

For what worth, here are the notes I took of the original assembly; not to say some of the hardware wasn't altered at some point Thank you for any insight. EDIT: I can't delete the image, which isn't quite right. So a corrected version is below.

[kwmech]

I took my truck to the muff shop and got a single 3'' exhaust dumping out the drivers side. Got a flow master double 2.5 to single 3 adapter. Magna flow muffler. Sounds great, cost was about 650.00.. It was nice getting rid of those lousy headers. I had already done the cast iron at the heads

[mr.mud1]

hi Tony.i'm a fan of Waldron's Exhaust in Michigan.i've used them several times.i did recently put new tailpipes from Waldron's on my truck,a 402/turbo 400 with leaf springs. i wanted 2 1/4 inch pipe rather than 2 inch.my front pipes were good til the last half so i made pipes to renew the back half of the front exhaust pipes and searched through the Walker catalog and found a set of mufflers with 2 1/2 inlets and the new 2 1/4 outlet.the mufflers fit in the stock hangers and the tailpipes are very nice.i have a little video of my truck running when i started the new engine for the first time,i'll sent it to you if you want to hear what my truck sounds like.take care.Greg

[Richard]

Like the sound of FlowMasters myself. The two and even three chamber 50 series are to loud for me at this point in my life. Most people will not spring for the added cost of the 70 series (AKA big block muffler) If you go that route, can guarantee the added cost is worth it. Presently have a single 3" on my 94. Get nice comments all the time. Deep throaty sound at idle and does not get obnoxious at wot. Plan is to run the same 3" muffler in a dual config with an X pipe on my LS swapped 72 build.

[70cst]

I'm stock except with Spentech mufflers.


https://www.youtube.com/watch?v=K1LXf66LGaY

[71CHEVYSHORTBED402]

Thanks for all the input. Still deciding on a muffler, I'm leaning at flowmaster 70s.

Think I'll give up looking for an exhaust kit, because at no surprise the tail pipes vary coils Vs leaf springs. The front pipes vary by W.B., so unless perhaps by mistake 99/1 they don't build a kit for my application. Not stock-ish anyway. Darn leaf springs, they're no blessing on SWB 2wd. I figured custom was in order anyway.

I read some places anything less than 2.5" pipe was inadequate. But a guy north of here tells me the original front pipes were 2.5" and the rears 2.0". Right again.

[mr.mud1]

hi Tony.the front pipes on my big block truck,the complete exhaust system in fact was original to the truck,2 1/2 inch front pipes and 2 inch tail pipes.you can see in the picture,the front 1/2 of the front pipes are still there and were in great shape.the ends were thin at the mufflers,so i made new ends out of 2 1/2 inch pipe for the front pipes,the Walker mufflers i told you about with 2 1/4 outlets and the tail pipes i ordered from Waldron's in Michigan.it all worked great.one more thing,i always use steel donut gaskets.i started doing that a 100 years ago when i worked at a muffler shop and still do.i find they stay tight and don't leak like the donut gaskets made from fiber,asbestos or whatever they are.take care.Greg

[MARKDTN]

I also will put in a plug for Waldrons. I wanted chambered exhaust for an early Mustang. Bought the kit from them and took it to my local exhaust guy. He says he usually charges extra when people bring a kit because they never fit, but he said this one was very close. They do list a kit for BB 4x4. You might at least call them.

[Sheepdip]

Flowmaster Super 40's with an "H" pipe sound the best to me. Not too loud and nice rumble.

[71CHEVYSHORTBED402]

Can't delete the first image (too late). Here's a corrected version of how I found the exhaust system, for what worth. Exhaust guy is supposed to inspect the truck for custom "any day now"

[71CHEVYSHORTBED402]

Originally Posted by MARKDTN

I also will put in a plug for Waldrons. I wanted chambered exhaust for an early Mustang. Bought the kit from them and took it to my local exhaust guy. He says he usually charges extra when people bring a kit because they never fit, but he said this one was very close. They do list a kit for BB 4x4. You might at least call them.

I did but nah. Nobody makes a system for this frame. Custom unfortunately, hopefully hung by the frame brackets. The guy hasn't come over yet Have a feeling I'm 4 months or so out for exhaust, can't run without it. Many specials are slow these days.

[mr.mud1]

hi Tony,the tailpipes Waldron's made for my truck are for a leaf spring truck.the factory exhaust pipe on the pass side was factory i'm postive and had the end heading for the muffler,that would have worked around the trailing arm if my truck was coils?the drivers side was different at the muffler end but also factory.tailpipes were no problem and i had them make them from 2 1/4 rather than 2 inch,again no problem.

[YellowK5]

I just installed a LMC exhaust system on my long bed..all aluminized pipes and mandrel bends..I had to cut it up as it was for a coil over truck not leaf spring but it work out very well when done

[1967GMCC20]

My 67 BBC running cast iron manifolds, dual SS Vintage Thrush mufflers... used my back half from previous custom V6.

$350... we have a great regional exh shop in a little tiny town. Get comments all the time on how nice it sounds. Nice old man rumble..you see it, you hear it and wonder what's in it.