1 3/4" Headers for my 406???

[Busted Knuckles]

I've found plenty of 1 5/8" headers but none for my '77 K-5 with 1 3/4" primaries. This engine will have GM's newly reworked Bowtie Vortec heads with 225cc runners and will sport a hydraulic roller cam. Plans are to set the rev limiter at 6500 and I want to make sure it doesn't nose over in the mid 5000 range.

 

[Busted Knuckles]

Surely somebody has small block headers with 1 3/4" primaries??? I'd hate to choke this thing with small pipes.

 

[dyeager535]

69088 is the part number for Hedman Elite(I think) 1 3/4" small block K5 pipes.

Their 1 5/8" pipes are excellent in terms of fit/plug access (short of the shackle issue with some of them) but I can't comment on the larger diameter stuff. They are pricey as heck on Hedman's site, but probably considerably cheaper on Summit. Still recommend checking out Hedman's site/notes for each part number, to find which one best fits your application.

 

[Busted Knuckles]

Man, you're a wealth of information!

I also checked on the P/N 69080, it shows to work on '82 up - what would have been the difference from '77 to '82 that would keep it from working on my '77? I can get these for less than $225 and want to get 'em ceramic coated flat black, so I'd prefer non ceramic.

 

[dyeager535]

To be honest with you, I can't answer why they chose the year breaks they did. Something dumb like '82 for mine. It MIGHT be the 6.2L diesel with the pinion snubber on the front diff, but I don't think that assembly would be in the way. But it could. 700R4 was '82+ as I recall, perhaps there could be issues there, although should be quite similar to the other autos before it in regards to shifter placement.

Hedman likely can't answer either...not everyone can know as much about all vehicles as we do about the trucks, but they tried to tell me a same year 'burb and K5 would be somehow different that would affect header fitment. Not their fault I realize, but you won't get much help in that regard. Craig (Artzner) might be able to help, he works for summit, no idea what their return policy is.

 

[Busted Knuckles]

I'm actually going to run a 700R4 on mine, so that would be fine. As long as I can get the collector in a reasonable place, I think I'm going to give it a shot. I'll be sure to post the results here...
Thanks for your help!

 

[dyeager535]

I'd see if you can't find some constructed in the same way as the 1 5/8" ones that don't hit the shackles in the garage post. I'd hate for you to run into the same clearance issues, besides, the 69890's I have hang way down below the framerail, and wheelers don't like that.

 

[Busted Knuckles]

Shoot.
I have a pair of FlowTech Afterburners that were on it with a 350 in it plus I have a new pair of Hookers, but both are 1 5/8". I may end up with the smaller heads and smaller headers, I think I'd get better mileage (yeah, right) and it looks like it would be a lot less trouble.