? about big block headers

[Yukon Jack]

I am swapping a 454 into my 1969 K20. I have it sitting in the frame now and have a problem with the passenger side header. *** Correction - I originally bought Dynomax Cermecoated 73-87 BBC 4wd headers. *** The collector on the passenger side is staring right at the transfer case and I don't think there is going to be enough room to make a bend to go up over the transfer case.

*** Correction Some have recommended I use the 67-72 big block 2wd headers. ***

It would help me a lot if I could get some rough measurements of how far your collector hangs down (nothing precise). A measurement from the bottom of the flange at the engine to the top of you collector so I know how far they hang down would be great along with I.D. of your header manufacturer and what application they are for.
Would also be helpful to get a rough measurement from the back of the flange at the engine to the end of the collector so I know about how far back the collector is from the engine.

If anyone who has done a big block swap in a 67-72 can tell me what headers they used and the application, that would be helpful too. Last time I asked, there was not a general consesus.

[Pont]

Hey Mark, I don't happen to have any measurements while I sit here and type this but I will get some for you if you like. My measurements probably won't help you though because I had to modify my passenger header to clear my transfer case.

I used Hooker Competition headers and had to cut about 4" of length out of the header at the collector on the passenger side. That was the only way I could get enough room to make a bend to run my pipe through the crossmember. My big block is also sitting back further than I think it should be, by at least 2 inches.

You might want to check with Breeh. He's running a big block and his setup is sitting a good 2 inches forward from where mine is sitting. I'm not sure if he's running headers or not but if he is, he might be able to give you some better insight on passenger side clearance. Seeing how I had to cut about 4 inches out of my header length, it still might be too tight in that area.

Best of luck, let us know what you end up doing! And let's see some pics of that bad boy sitting in the frame!

[breeh]

I didn't run headers because I couldn't get a definite answer on what would work well. I did have a set of Hooker Super Comps that I was running on my 67 'maro that I tried to fit in the 4x4 but they would not work. I finally ended up using cast iron. It was not that important to me because I don't take my truck above 4500 RPM and the stock manifolds can flow at that rate OK. Good luck and let us know if you find something that works well.

PS
I think MOTHERTRUCKERS posted once about a set of headers that will fit a big block 4x4.

[Yukon Jack]

I spoke with Ed (Mothertruckers) after I purchased these headers and he said he usually uses the 67-87 2wd headers - so I will probably end up sending these back and exchanging for those.

I asked the same question over at ColoradoK5 as a bunch of those guys are running big blocks and have had the suggestion of headers for a 78 Nova and 68-72 Chevelles. I probably call Dynomax Monday and talk to them about the issue.

[nathan_454]

Hedman hedders part number 691110 or 69110 cant remember is for a 67-72 chevy 4x4 big block, I have these one my blazer and they went in great, clears everything!

[SuperStock46872]

I have been told that 73-87 specific headers will not fit a 72 and prior because of the way the frame is shaped, never tried it though.

I have headman #69130 in my 72, they are 2" primary with the usual 3" collector. They fit decent. I had to "persuade" a few of the tubes to fit however, no t-case problems though. #69130 is listed as a header for a 69-87 2wd truck and factory big block mounts. I did not have those mounts so that is why I had the problem, I am sure.

One thing the watch though is the bolt in the bottom of the shackle of the passengers front spring. I had to flip it so the extra threads went to the out side and not the inside. Otherwise it interferes with the collector area of the header.

how are you guys moving your motors back 2", did you clearance your firewall for the distributors or what?

my rig was a factory equiped with a 350, and i reused the 350 mounts. I had to cut some metal off the crossmember for oil pan clearance. otherwise the motor was tipped forward too much, moving it back would have helped this, but them there would be no room for hei. I had to clearance the firewall right by where the clutch linkage comes through, if you have a stick it might require some craftsmanship to make it all work. By the way my pickup has a 3" body lift and I used factory low rise valve covers. Other than the crossmember i had no problems installing the 468. It will pass every thing but a gas station

I did all the work myself so if you have anyquestions feel free to ask. After the swap my only regret was waiting 2 years to do it!

[Yukon Jack]

I went back and edited my original post as I listed my original headers as the wrong ones. I originally had bought the 73-up 4wd headers and they definitely would not have worked. I have ordered the 67-72 2wd headers and got the specs from Dynomax and they look like they should work good.

I am going to be using an MSD ready-to-run distributor and since it is smaller than an HEI I think I will be okay firewall wise. I am doing a 2" body lift for a different reason but that should help on clearnace issues also.

My original crossmember is fine - guess it really depends on what oil pan is on your engine.

Thanks for you input, I wouldn't be doing this swap without the info from this board!

[SuperStock46872]

For the record, i used a stock oil pan from a 77 burb.

[chevypete396]

Jack, Did those headers work? I use the same headers as SuperStock46872 does with the same minor clearance issues plus I had to remove the zirk fitting on the front axle to keep it from rubbing a hole in the collector. If yours fit better let me know... Pete.

[Yukon Jack]

The driver side looks great with no mods apparently needed. Even looks like the oil cooler won't be a problem. The passenger side won't slide into place and I haven't been able to get a grinder out to work on the frame yet. Doesn't look like I will have to take off to much metal to make it work. Hopefully get out to do that Tuesday or Wednesday night. I'll get some pics and let you now when it is installed.

[chevypete396]

Looks like you might have found some winners. Thanks... Pete.