86 Sierra 350 exhaust help, passenger manifold

[Unpredictable1]

The heads were changed on my truck quick some time ago, and the passenger manifold that was original to the truck, the back manifold bolt hole extends past the head slightly.

For reference, an ATP 101099 manifold has the same fitment problem. This manifold is identical to the factory one, and it lists 81-86 years for application. I've attached a picture. Center to center of the last pair of bolt holes is about 3 inches, I would need it more like 2-2.5 I think for it to line up.

So either the rebuilt heads I have are before or after that time period. The driver side manifold fits without issue. My valve covers don't have center bolts.

The conundrum I'm in, is I have a nice cat back that I had a muffler shop install, a single with a flopro muffler, that travels under the driver side of the truck and exist behind driver wheel.

So I would think longtubes would essentially make me have to replace my whole exhaust (unless someone can tell em otherwise), if I could find shorties that would be a direct bolt in, I'd put them in.

Or, I'm thinking the cheapest solution, is some how try and find what manifold matches the head I have. If someone can help me zero in on what I need for this option which I think would be the cheapest - I would sincerely appreciate it.

My plans for this truck? Sometimes a daily driver, always ready for chores, maybe fuel injection down the road but it won't be winning any races or hauling big trailers.

thanks in advance.

 

[HotRodPC]

Is this not a passenger car 267/305 exhaust manifold?

 

[CSFJ]

I believe the 305 equipped trucks also had that passenger side manifold too. at least the one I owned did.

 

[crpntr78]

I had a similar issue with a truck I bought. It had a 350 from the early 90's in it with the center bolt valve covers. The PO just ran it like so I just thought it was a broken bolt. To my amazement when trying to fix an exhaust leak with new gaskets I found there was no bolt in it. The hole didn't line up so I took the manifold off and kinda wallowed the hole out with a drill bit and made it work that way.

 

[Unpredictable1]

I had a similar issue with a truck I bought. It had a 350 from the early 90's in it with the center bolt valve covers. The PO just ran it like so I just thought it was a broken bolt. To my amazement when trying to fix an exhaust leak with new gaskets I found there was no bolt in it. The hole didn't line up so I took the manifold off and kinda wallowed the hole out with a drill bit and made it work that way.

If I do that, I'd be getting into the exhaust chamber of the manifold. (at least that's what it looks like to me)

For those mentioning the 305, yes, it's for both the 350 and 305. (even includes the 6.2 on their webpage)

 

[CSFJ]

I don't know if there is a 350 only manifold that matches the output of the one you have. At least I've never run across one. I can take a look at the one on my '87 when I get home, it's a 350 tbi, but those will have the ports for the smog stuff in them.

 

[HotRodPC]

I don't recall ever seeing that manifold on a 350 that has it's factory manifolds. I've seen them on 350's where the truck was originally a 305 and a 350 swapped in. I can't find my pics now, but I had some matched set 305 manifolds from a truck and I didn't think that last bolt hole was that far out. I know had pics of them cuz I was going to send them to someone on here. Maybe I didn't look them over close enough to notice. Never really got all that interested in Wee O Fives so I very well could have overlooked that.