Need recommendations for TBI 350 exhaust

[93FatBottom]

Last night I picked up a 1975 Suburban K20 with a TBI 350. The previous owner had an 87 Suburban V20 with low miles that was t-boned. So he decided to swap everything from that one over to the 75. Did a great job, everything works accept cruise control and the A/C needs a charge. I mainly bought it because it was under $1,000, was a 3/4 ton 4x4 and its a 1975 so no smog for me The only downside is the PO used the 87 front clip

The PO also put the entire exhaust system on, including both cats from the 87 TBI 350. He said he did this to save time and money. When I got home the rear cat was making an annoying tapping noise, so I'm sure its about to **** the bed. The front one is that crappy pancake style, which is super heavy and bulky. My y pipe has been hacked and rewelded multiple times, it appears for the purpose of clearing the front driveshaft. Quick decision, its all gotta go!

I'm currently trying to decide if I want to swap in a LQ4 6.0 or a Cummins 12 valve, but because I plan to offroad this truck in sand, mud, trails, and some rocks, I've pretty much rulled out the cummins just for the sake of the weight. In the mean time, at least one of these cats is collapsing on itself, and I'm only working part time while I finish school, so I dont have the coin for the swap yet, so I'm looking to do a cheap exhaust for the Burb.

Right now, I'm trying to decide if I want to do true duals or dual in single out, and which muffler I want. I want it to sound mean, but its just a stock TBI 350 so only so much can be done lol.

If I end up doing dual in single out, I am looking to run dual pipes back and cross over behind/under/over the trans so I don't have to worry about drive shafts hitting. I would prefer a turn down or turn out exhaust right after the muffler before the rear wheel(s). The other concern I have is back pressure. I want this thing to run strong and efficient.

I would love to hear your opinions guys! I'll take lots of pics later this evening before sun down so you can check out my new toy. Thanks!

[Front Range]

TBI with dual exhaust and Dynomax Super Turbos. Healthy sounding but not annoying.

[93FatBottom]

Originally Posted by Front Range

TBI with dual exhaust and Dynomax Super Turbos. Healthy sounding but not annoying.

Thank you for the response. My cousin has a 73 K10 with that very exhaust. His sounds way good.

I'm thinking about true duals with those mufflers with 2.5" pipes but with turn downs before the axle. I'm wondering though. My truck is a TBI 350. I don't need the cats so those are gone. For back pressure, is it better to do an X/H pipe crossover or am I good leaving them as straight true duals? I had an 88 Suburban and I cut the cats and muffler off and had a shop weld a straight pipe from the factory Y pipe back to behind the axle and it was loud and annoying and got horrible MPG. I'm hoping I get some advice, I have to take it on a long trip next Friday. I called a local shop and they have the mufflers and pipe in stock, but I didn't even think about the X/H pipes until tonight. Any advice?

[68Timber]

Originally Posted by Front Range

TBI with dual exhaust and Dynomax Super Turbos. Healthy sounding but not annoying.

I've used this combo on several trucks over the years. Good sound, never annoying. As far as the x or h pipe goes, personally I've never paid to have one installed, but everyone agrees that it makes for a more efficient exhaust and will help tame an obnoxious exhaust. Bottom line though, that'd be your call. It won't be necessary with those Dynomax Super Turbos but it won't hurt either.

[Front Range]

I've got a 77 longbed.

1990 TBI 5.7 with working EGR and all sensors

Hedman elite headers w/ 02 bung / working sensor

2.5" exhaust, with crossover pipe - located right at the end of the transfer-case output shaft housing

No catalytic converters, pipes run over the axle and out behind the rear tires

Never had any run-ability issues or codes from the OBD1 system due to back pressure. I had the crossover pipe added in to "balance" the exhaust flow between sides. Runs good, sounds good, and have had no problems with regular use over a 10 year period.