Headers?

[prairieschooner]

I recently purchased a very stock 1975 C10 Short Bed. I am wondering if I want the hassle with Headers but looking for more power. It currently has Single Exhaust so thinking of this kit by Dynomax;
https://www.summitracing.com/parts/w...SABEgJeDvD_BwE

Advice would be appreciated, thanks in advance
Steve

[Dead Parrot]

Double check the emissions requirements for your location. Would suck to install a shiny new exhaust only to have to rip it off to make some inspector happy.

If it still has the pancake (pellet) type converter, replace with the newer honeycomb to get a significant reduction in back pressure. If that truck ever had a converter. HD emission versions didn't have much emission stuff. Emission level should be on the air cleaner cover or the SPID.

For a stock truck, headers won't magically add a lot of HP over a decent dual exhaust.

For most headers, you will need a new bracket for the AC compressor and a short piece of pipe for the PS bracket where it bolts to the driver's side manifold.

Some folks have few issues with headers. Others have to frequently replace gaskets that burn out or otherwise start leaking.

I suggest starting with a basic tune up and advancing the timing curve. The stock tune on 75 trucks was set more to meet the then new emissions standards then provide the best power or efficiency.

[KQQL IT]

Buy good headers and they're maintenance free.
Have doug thorleys on 2 of my trucks and don't touch them.
Although bone stock-
a good tune up would be a better improvement than any headers would.

[Loco83]

If you have to run single go with a 3" full exhaust, got rid of my stock exhaust and ran 3" from the Y pipe back, 3" Magnaflow cat and Flowmaster.

[prairieschooner]

Thanks guys,
When I got the truck the PO had installed an Edlebrock 1407 without the adapter on the stock manifold. The secondaries could not open up. It also had poor spark & crapped out at mid-range. I confirmed that it had a 350 and most likely the original engine with a build date of June 1974. I ran a compression test with all of the cylinders within 5 lbs of each other. I then performed a complete tune with plugs, plug wires and new distributor and a new Edlebrock #1406 Carburetor. It runs great now and towed my boat (a 1959 Glasspar Avalon) on a four hour run without any issues. I also have a 1958 Airstream 18' Traveler that will make it's way behind the truck.

Back to the question~~~I don't need to stay with a single exhaust since here in Cali the cut-off date is 1975 for SMOG crap but will be saving it in case we move. There are plugs in the exhaust manifolds from the SMOG Pipes making me wonder about replacing them at the same time as I deal with the exhaust. The minimum I want to do is dual exhaust with maybe Turbo mufflers (Flowmasters are too loud for my near 70 year old ears). I'm looking to help the mid and upper end performance but don't want to loose the bottom since I will be towing.
Thanks again

[KQQL IT]

I think 75 is no inspection yet?

To your question I've had great luck with doug thorley headers.
I have these on my 73 fit perfect and zero maintenance

https://www.summitracing.com/search?...rder=Ascending

Also had tri Y style in my 77

https://www.summitracing.com/parts/dte-300y-c/

Both fit great.

[Palf70Step]

I've used Hedman Hedders #69010 on a couple squares. I really likes the fit and the fact they didn't hang low.

https://www.summitracing.com/parts/h...olet/model/c10

I also used header style plugs to make it easier changing/accessing them
https://www.summitracing.com/parts/acc-8199/

[Ziegelsteinfaust]

I prefer the car headers on the C10 they tuck up nicer.

Also i got a summit 2.5 inch exhaust for my car, and while not hard. It is a bit fiddly to do on your back. Jack it up as high as you can, and level. Get a bunch of jacks, and blocks of wood to level it off as you build it. Then only 2 tracks at each joint till your happy with the results.

Also if you plan to do all this. It maybe a good idea to upgrade now vs later if your planning on a big motor.

In the engine masters show they got more horsepower with good mufflers vs cheap mufflers on a larger pipe. Straight through equals the most power. Also they did a budget shoot out, and the results are quite amazing.

[Dead Parrot]

Since the emissions aren't an issue:
Bump your initial timing up to at least 10 BTC and maybe more. The stock 350 likes lots of advance. If it gets hard to start when hot, back off some. (very likely the old dizzy had a rotted vacuum pot and frozen in place mechanical advance.)

Ceramic coating on headers helps with both under hood temps and rusting on the headers.

I had horrible luck keeping the flat 3" collector gaskets sealed on my set of Dynomax headers. Don't remember the model number, they were purchased in the mid 90's. One of the lower cost ceramic coated version. After several years, had the exhaust shop just weld the exhaust pipes to the headers on the thought that by the time the aluminized exhaust pipes rotted out, the headers would needing replacement anyway. Everything is still holding together today although one of the mufflers may have a small leak. Mufflers were the shop version of a turbo muffler. Decent sound when you get into the throttle but not pain in the ear loud cruising down the highway.

I have read that the OEM vortec manifolds are good flowing. Found a set without the AIR holes for when my headers give up.

Run the pipes all the way to the back bumper. A lot quieter in the cab then the in front of the wheels setup. I had mine angled out to the sides rather then straight back.

[SCOTI]

Originally Posted by Dead Parrot

Since the emissions aren't an issue:
Bump your initial timing up to at least 10 BTC and maybe more. The stock 350 likes lots of advance. If it gets hard to start when hot, back off some. (very likely the old dizzy had a rotted vacuum pot and frozen in place mechanical advance.)

Ceramic coating on headers helps with both under hood temps and rusting on the headers.

I had horrible luck keeping the flat 3" collector gaskets sealed on my set of Dynomax headers. Don't remember the model number, they were purchased in the mid 90's. One of the lower cost ceramic coated version. After several years, had the exhaust shop just weld the exhaust pipes to the headers on the thought that by the time the aluminized exhaust pipes rotted out, the headers would needing replacement anyway. Everything is still holding together today although one of the mufflers may have a small leak. Mufflers were the shop version of a turbo muffler. Decent sound when you get into the throttle but not pain in the ear loud cruising down the highway.

I have read that the OEM vortec manifolds are good flowing. Found a set without the AIR holes for when my headers give up.

Run the pipes all the way to the back bumper. A lot quieter in the cab then the in front of the wheels setup. I had mine angled out to the sides rather then straight back.

I agree on Ceramic coating headers. It helps w/temps & corrosion. Not sure how good the manufacturer supplied coatings are but if I were spending the bucks I would want some kind of extended warranty because they sure do charge a premium for them. If they don't offer a legit extended warranty, I'd get some cheaper units & have them coated somewhere.

I bought used car headers off C-list for my dually ($50). They were F-body/A-body full length 1 3/4 tube w/a 3" collector. I made new thicker 3-hole flanges (3/8" material) & welded them on @ the ends of the header for a nice, flush, sealed end. I also built matching flat SS flanges for the head-pipes. The truck has 7k miles w/the same set of gaskets top/bottom w/zero leaks. The thicker, flat flanges work great for sandwiching the gasket material & allow using old fashioned/cheap off the shelf collector gaskets.

[SilverMiner]

Originally Posted by KQQL IT

Buy good headers and they're maintenance free.
Have doug thorleys on 2 of my trucks and don't touch them.
Although bone stock-
a good tune up would be a better improvement than any headers would.

I am in agreement with KQQL here. In the past 18 months I added Hedman 69230 headers to my 1980 K10 Suburban. They installed beautifully, work fine, but I have experienced no noticeable increase in my Butt Dyno to justify the purchase. The inconvenience of changing spark plugs have not been compensated by any greater power. I wish now I would have kept the factory logs just for the convenience factor.

[KQQL IT]

Originally Posted by SilverMiner

I am in agreement with KQQL here. In the past 18 months I added Hedman 69230 headers to my 1980 K10 Suburban. They installed beautifully, work fine, but I have experienced no noticeable increase in my Butt Dyno to justify the purchase. The inconvenience of changing spark plugs have not been compensated by any greater power. I wish now I would have kept the factory logs just for the convenience factor.

The Doug d310c don't require any extra drama for the spark plugs.
Even use a off the shelf wire set.
Even with angle plug dart heads I have on my 73.

[prairieschooner]

Originally Posted by SilverMiner

I am in agreement with KQQL here. In the past 18 months I added Hedman 69230 headers to my 1980 K10 Suburban. They installed beautifully, work fine, but I have experienced no noticeable increase in my Butt Dyno to justify the purchase. The inconvenience of changing spark plugs have not been compensated by any greater power. I wish now I would have kept the factory logs just for the convenience factor.

After reading this thread I am now thinking of keeping the Factory Exhaust Manifolds and simply upgrading to dual exhaust. I may want to go to a better manifold but that will be a different thread.
You guys are great!! Thanks again for the advice.