Hi All, I just recently purchased a 74 C3 and wanting to add hassle free headers, I have been looking at Summit Racing and came across "Doug's Header" D380 and want to see if anyone has any experience and tips on these or is there any suggestions on which headers to use.

 

I’ve not used these, but it’s worth noting that they are “sidemount headers”, meaning they are meant to install side-pipes. Is that your plan?

Also, “hassle free headers” is likely an oxymoron. My post history will show that I am a proponent of headers, but you should expect exhaust system fabrication at a minimum, and they’ll likely require some three-dimensional thinking to get them installed. My experience having owned headers is that oil changes, working on the starter, oil pan, idler arm, steering box and spark plugs will be impeded by the headers. They do deliver great performance gains across the powerband of the vehicle, though - worth it, IMO.

 

I have had great success with Hedman Hedders as they have bolted right up without any modifications. I used them on both a small block and on my big block and both times they slid right in without any tapping, flattening or re-shaping of any kind. I have not been impressed with the quality of the ceramic coatings but that is a fault of the coatings and not of the headers manufacturer.

All the horror stories I used to hear about headers have just been "stories" as I have not had to re-torque them nor have I had any header gasket failures requiring replacement. The Hedman headers are of a quality that has lasted over 2 decades in use on the 427 and they are still on the C3. My car is a four speed convertible with power steering and even with the accessories the headers were a easy installation. I can still change all 8 spark plugs from the top even with headers. I like the way they look and I hope they are worth the expense but the factory exhaust manifolds used on the big block engines were pretty good flowing parts all by themselves. I noticed a bigger difference in the power output when I converted a small block to headers than when I switched the 427 to headers. The small block had the Ram's Horn style exhaust manifolds where the big blocks use a better flowing design that looks more like the parts used on the newer LS engines.

The ceramic coatings are a big help in under the hood heat and worth the extra cost. I have used several sets of the ceramic Silver coatings and the problems have been that they just don't hold up in my applications. After a few years they look nasty because they develop spots and places where they change colors.

 

Thank you for the input this is great info...

 

Thank you for the input much appreciated

 

make sure they are listed as fitting or made for a corvette. Someone else just bought headers for chevy motors and they hung down too low for the vette. THey wouldnt line up for the transmission crossmember if you are going to the rear under the car

 

Thank you for info, especially the "fitted"... Thanks again for the input...

 

I had Hedman "Hedders" on my 78 small-block and, unfortunately, my experience was not the same as yours. I had plenty of header gasket failures and had to re-torque frequently.

Those Hedders had 1/4" flanges, supposedly thicker flanges are better and I have had setups with thicker flanges that were less troublesome.

On your big block, the header primaries go underneath the plugs instead of over, under, around, as they do on a small block. Frankly, I think my issues are more with the fact that G1&2 SBCs were designed well before your BBC, less so an issue with headers conceptually.

 

I used summit racing brand headers on my 75, mid length, part number G9103.
There were zero fitment issues, no denting required. I had an exhaust shop fab dual exhaust from the headers back. They do require a mini starter tho, like most headers.
They have been on the car for 4 years now and I still have zero complaints with them.

 

I’ve had no figment issues with the Doug’s headers sidepipes on my ‘71. They have a heavy flange so header gaskets don’t usually fail.

 

I have Obx stainless headers and sidepipes on my 74..(same style as the Dougs headers you mentioned above but less expensive for me ). I did have to dent one of the primaries to clear the power steering box with my old dart heads... Now that I swapped to aluminum heads I see I would have had enough clearance without denting the primary. My point is there are a lot of variables that will make experiences and fitment different for different owners. Other than that Ive been very happy with my headers and sidepipes... They give me more clearance and less heat at my feet. XS power also sells rebranded OBX headers for our cars.

 

The headers and side pipes were on my car when I got them, so I don't know what brand they are, but I've yet to find any maintenance that they interfere with. I've changed oil, starter, power steering components, etc.

 

The Doug's D380 headers have a primary ID of 1 7/8" -is your Small Block 500 hp or more? IF it's mostly stock or 3xx hp, a 1 7/8" header will give up more torque than it will get you back at high RPMs that you won't use... It's honestly silly that the C3 header that Doug's standardized on is that big considering that there's so few 500+ HP SBC-based C3s out there...

You need a header with a smaller primary ID for a stockish or even up to 350 hp SBC or you're just giving up area under the curve. The header having high velocity is important to performance.


Adam

 

I put the Dougs 380 on my 4 speed, AC, car. Fit perfect with no interference anywhere.
Worth the money. Need to fab exhaust back to the cross member.

 

This is true but the losses arent all that much...
here are the dyno results for a sbc 400. my little 355 with the heads, compression and cam I have is mathematically capable of 420hp when all the spec are entered into desktop dyno which means I probably would benefit the most from smaller primaries but then again ive read the same thing over and over about my 200cc runner heads vs the 180 cc heads I just removed for them and the dyno testing engine masters has done as well as the better performance in my car has shown this stuff just isnt always accurate the fact that I had to jet up and increase my squirter size with the new heads indicates there was more flow to be utilized by the engine with the larger heads dispite the relatively small 270 roller cam.

• 1 and 5/8 headers – 519.7 lb-ft of torque @ 4,600 RPM / 529.7 hp at 5,700 RPM
• 1 and 3/4 headers – 519.3 lb-ft of torque @ 4,600 RPM / 539.1 hp at 5,700 RPM
• 1 and 7/8 headers – 513 lb-ft of torque @ 4,900 RPM / 539.6 hp at 6,300 RPM

https://www.motortrend.com/news/engi...episode-wrong/

In other words, the larger headers will cost less losses than your average mechanical fan vs electric fans which so many say isnt worth worrying about.

 

Dougs makes a quality product...and god forbid theres an issue they stand behind it.
I got one that had a defect that couldnt be fixed they replaced it no questions asked

Their coatings on mine anyways held up great. didnt get dull turn colors, nothing
Hookers may have improved over the yrs but alst coated set I had wasnt all that great.
You can buy them uncoated and send them to jet hot, swain etc for a top notch coating
come in all different colors these days, love old school white.

 

I used Flowtech ceramic coated long tubes on my 76, small block, stick shift, Borgeson steering box, PS, AC. I'm very happy with the fit, I can access all the header bolts and spark plugs and there's plenty of clearance around the factory starter, steering box and, very importantly for me, the clutch linkage.