Headers on 350 with SM465 2WD

[Dodg3m4n]

Hi everyone! I’m new here and this is my first post. I’ve been doing some research and haven’t found exactly what I’m looking for or maybe I did and just read past it. My father in law gave me two or three sets of long tube headers for a small block but I have no idea what they are supposed to fit. My issue is that I have a non-hydraulic clutch linkage SM465 and I’m worried that they will interfere with each other. Any other problems that arise I’m not as worried about but I kinda need the clutch linkage to move so it’s still drivable. I almost forgot this but she’s a 78 C20 2WD. I was perfectly okay with the logs staying on until I found an auto to swap in but my passenger log split almost all the way around. Thank you all in advance!

 

[Bextreme04]

I think @Catbox is running longtubes on a SM465 2wd.

 

[Bextreme04]

oh, but his is a 454

 

[AuroraGirl]

oh, but his is a 454

I dont know it spatially but if the two engines were theoretically in the sameplace on the same mounts, how far away or Up/down are big block ports(not counting the spacing) from a sb? Id think if the shape is one that isnt too extreme it would be ok but i guess im not sure

 

[Bextreme04]

I dont know it spatially but if the two engines were theoretically in the sameplace on the same mounts, how far away or Up/down are big block ports(not counting the spacing) from a sb? Id think if the shape is one that isnt too extreme it would be ok but i guess im not sure

Well, I have longtubes on the 350 in my truck right now, and they are significantly shorter than the ones I have for the 454 that's going in there. I didn't take a picture, but I put them side-by-side and it was substantial. Not just front to rear, but height wise too.

 

[shiftpro]

Hi Justin welcome and thanks for joining.

You absolutely want long tube... short tube only helps high rpm.
But... are these truck headers? They have to fit the vehicle, not just the engine. You might have to physically try to get them into place
to see if they work. But that means you would have already pulled the old manifolds and exhaust so you're kind committed at that point.
Maybe you could stary by determining if the father-in-law gave you two or three sets. I mean, 4 or 6 it shouldn't be too hard to determine.
Then look at differences between the sets you have... maybe start by eliminating what you can determine will NOT fit.

Also it's totally normal to bash clearance dents in the tubes where they touch or are just too close for comfort. I would check out Heddman and Hooker to see if they have a different model for the older squares with a mechanical clutch. I have installed headers on these trucks with a clutch linkage but I didn;t biy the headers... so I don't know if they were specific or not.

 

[Dodg3m4n]

Hi Justin welcome and thanks for joining.

You absolutely want long tube... short tube only helps high rpm.
But... are these truck headers? They have to fit the vehicle, not just the engine. You might have to physically try to get them into place
to see if they work. But that means you would have already pulled the old manifolds and exhaust so you're kind committed at that point.
Maybe you could stary by determining if the father-in-law gave you two or three sets. I mean, 4 or 6 it shouldn't be too hard to determine.
Then look at differences between the sets you have... maybe start by eliminating what you can determine will NOT fit.

Also it's totally normal to bash clearance dents in the tubes where they touch or are just too close for comfort. I would check out Heddman and Hooker to see if they have a different model for the older squares with a mechanical clutch. I have installed headers on these trucks with a clutch linkage but I didn;t biy the headers... so I don't know if they were specific or not.

I don’t remember and I’m not at my storage spot to see if it is two or three sets. I know 2 sets for sure and I know one set came of an auto C10. I’m not above putting dents in them to fit I’m just worried about having enough room for the clutch linkage.

Thank you everyone for the replies

 

[Catbox]

I have a 454 & SM465 with long tubes on it.
My set of headers are made for a Nova and fit like a champ.
They clear the clutch linkage with no issue.

The best thing you can do is pull the manifolds and try the headers out to see where they might be an issue.
There may be a part number stamped on them somewhere that you can look up and see what the original application was.

This is what I had to work with...
A crusty set of BBC headers for a Nova.

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This went on with no new dents needed in the tubes.

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Here you can sort of see the Z-bar linkage down in there...

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[Dodg3m4n]

Catbox do your headers go under the Z bar? Ground clearance will only be an issue if I lower it but that’s a discussion for a different day. And for todays dumb question of the day, would I drop them in from uptop or from the bottom up?

 

[Turbo4whl]

Catbox do your headers go under the Z bar? Ground clearance will only be an issue if I lower it but that’s a discussion for a different day. And for todays dumb question of the day, would I drop them in from uptop or from the bottom up?

There are no dumb questions, only dumb answers. You usually can fit them from the bottom up. Vehicle hoist is handy because many times you need to angle the collector end down as you thread them up.

Remove the oil filter and sometimes the starter for more room. Also if you remove the starter to get the header in place, after the header is up, leave it loose and bolt the starter back in first.

 

[Turbo4whl]

I should have also said remove the spark plugs too. Pain in the butt to remove half of a broken spark plug from the plug wire.

 

[bthomas]

Is there that much diff between 2wd and 4wd sm465 headers?

 

[Big Chip]

Try GM A body headers. They sit up above the bottom of the frame rails. Maybe try finding a cheap used set for a few bucks on marketplace or craigslist just to see if you can't get definitive info about fitment.

 

[Catbox]

Catbox do your headers go under the Z bar? Ground clearance will only be an issue if I lower it but that’s a discussion for a different day. And for todays dumb question of the day, would I drop them in from uptop or from the bottom up?

They fit under the Z-bar.
When my kid installed them, he removed the starter and plugs.
Everything slid right into place from the bottom of the truck.

With the car headers, you will have no issues with ground clearance as they tuck right up in the chassis.

Here I am looking straight across under the truck and they are not at all below the chassis rail. Truck specific headers are not tight like this.

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I have to lay on the ground to get a view of the collector at all.

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