New SBC Truck Exhaust - Which Headers?

[Boostaddict]

I need to re-do the entire exhaust on my 1980 GMC truck from the heads back. Its all rotted and super restrictive (single 2.25" exhaust). Its a chevy 400 with 350 heads on it and crappy cast manifolds. I'd like to put some decent headers and will likely build a custom 2.5" stainless dual exhaust unless I can find something else reasonably priced. There are SO many freaking headers available for the 350/400 motors. How do I begin figuring out which I'd want. They start super cheap (talking $100 a pair) and quickly go up to $1000+. Doing some searching I see lots of guys using Hooker and Hedman headers. At a minimum I want ceramic coated for corrosion resistance. I see some guys saying to use tri-y headers which I know are great for a turbo motor but not sure about n/a. There are long and shorty headers available. None under $1000 look to be stainless. I want something that will let the engine breathe easier... not looking for power just overall efficiency and if they happen to be reasonably priced then great. I'm not an American muscle car guy so I'm constantly learning about all of this. Any suggestions?

[j2k4]

One of the tri-y headers' main attractions is that their design is more likely to result in close to equal-length primary tubes, which makes carb-tuning a bit easier and cylinder-to-cylinder conditions easier to duplicate.

That said, it's a truck, and unless it's gonna be a comp truck, it doesn't matter a whole lot.

SBC headers are usually not a fitment problem (it's SBC, after all; if they can't do it right by now...), so I'd spend enough to get good metal, and get them ceramic-coated somewhere, rather than try to buy them that way - I think you'll save a few bucks.

Apart from that, truck headers tend to have just enough primary length to get them under the vehicle, so as to keep them out of the way of other things.

I would also recommend spending some money on mufflers that will handle minimum 2.5" in-and-out.

Larger pipe between header and muffler will help torque slightly.

[Boostaddict]

Thanks for the input. Yeah, I'll probably get them ceramic coated here locally. Everything from the headers back will be quality stuff... I have a bunch of stainless mandrel bends laying around and I'll get some good stainless 2.5" in/out mufflers. The truck is an original owner/family vehicle with only 30k miles so we want it to last forever (I don't cut corners unless necessary) and I don't want it to be obnoxiously loud either . I'll start shopping around...

[j2k4]

Good plan, then.

Keep the old metal rolling, brother.

[Irocurstang]

I put some flotech headers on my dads 86 chevy, bought them from SFX performance on line for about 150.00. Nice headers with good flow and at a awesome price. If your looking for power and economy go hooker but they tend to be a little spendy. Keep in mind that "SHORTYS" usally take more time to install and modification on most vehicles. Long tube headers are good for price,economy and a nice easy install. I put hooker shortys on my 87 camaro and they fought me the whole way id stay away from shortys for a truck.

[Boostaddict]

I found a pair of lightly used Doug Thorley tri-y headers for my application that I couldn’t pass up ($150/shipped). Made in the USA FTW. I’ll get them ceramic coated (they come with a nickel/chromium plating) and I need to start researching mufflers ASAP since the exhaust fell off my truck yesterday when I was driving down a really bad dirt road.

I was planning to do a true 2.5” dual exhaust with individual mufflers. I could also consider maybe doing a single muffler with dual 2.5” inlets and a single 3” outlet. I want it to be as quiet as possible (except maybe under high load) so internally baffled mufflers are probably necessary. Right now I’m thinking Flowmaster 50-series delta flow (not the obnoxious 40-series) or maybe chambered magnaflow mufflers. Stainless versions of course. Anyone have experience with this sort of exhaust and how loud it might be? As long as the mufflers are not straight-through and not the $40 specials I’d think I should be fine.

[j2k4]

I think that's a plan.

I'm not up on the brand-new stuff, but you'd probably do well to define "quiet" as precisely as possible - 'mellow' is descriptive and appropriate for performance, as I'm sure you are aware, but you could probably find something that would be, for all intents and purposes (even with the headers), land-yacht silent, especially as you're willing to ante up the cash for good stuff.

Nice score on the Thorleys, btw.

[Boostaddict]

Thanks. My version of quiet in this case is “as quiet as possible for the $”. Ideally something that approaches stock v8 truck quiet at idle and cruise and only gets rowdy with increasing pedal travel. The truck already suffers from extreme wind noise at cruising speeds above 50mph so the last thing I need is a droaning exhaust when all I have is the factory single-speaker am/fm radio to drown it out. I’m not really looking for “performance” gains since the truck is rarely driven and is only used for truck purposes, but I want to keep it nice and everything I replace is with high quality parts whenever possible. If I can gain any fuel economy that would be ideal tho, haha. With the 400, rv cam, small stock wheels/tires, and low gearing I already have more torque then I’d ever want.

Next on the truck agenda is to change the gearing for more ideal highway travel. I need to temp install a tach so I can see what the engine is spinning at. I’ll likely be changing the gearing and getting slightly bigger tires early next year to fix this. I need to install a heavy duty hitch and possibly re-do the body wiring harness which is going to suck. I want to be able to tow my vr4 with the truck next year. The interior needs some TLC, yada yada yada. If I put a 1/4 the effort in the truck to fix it up as I do in my vr4 it would be cherry. Its fun learning about this old stuff though.

[j2k4]

Full tailpipes should kill any 'drone'.

I found trucks generally fun to work on because of the room.

Always liked to finish a job with knuckles intact.

That 400 can be a torque-monster, and the headers/RV cam recipe suits it to a tee.

Too many people think that, because it's a small-block, it'll be happy revving like a 350 - that's when they discover the big main journals result in a bit too much bearing-speed for long life.

More 400s ended up as scrap because of that than the head/steam-hole/siamese-cylinder problem.