Careful. That’s a slipper slope of reworking wiring.
CK5
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'86 Jimmy 4in Lift, 40’s, tons, 8.1 Swap- 700r4 said PNNNNN
- Thread starter GWeakland620
- Start date
This is not a dedicated trail rig, but does trailer to the destination usually. I am currently in the planning phase of doing a 52/56" spring swap, and getting back to being more road worthy.
I need to though. I can’t have a sexy looking 8.1 in here with wire nuts in part of the harness lol.
I told myself no more ghetto crap.
It’s worthwhile. I’m a fan of my work so far.
Glad you didn’t paint the intake black like an ugly plastic intake manifold.
Martin
Martin
I have been debating this same thing recently. My big block has cracked manifolds and I'm debating doing new Dorman manifolds or headers. I don't like cheap headers and the problems associated with them so that raises the price on them to get decent ones. Manifolds are like $250 maybe from Dorman. I would probably gasket match manifolds at least. I am bone stock so I know I don't need headers for the flow or anything like that. I can't remember if it was @F.S.F.W or @78K30 that bought some cheapie stainless headers and how they were working out still. I shall be watching you so make a good decision. LOL
I'm pretty sure stock 8.1 manifolds will hit the frame in a few spots on a square body frame. But you can go with any other stock 7.4l 454 manifolds from any year prior and it should be good with clearance issues.
So with that being said, you can go look all over the internet and find results of headers vs manifolds. Headers will always flow at least a little bit better than stock manifolds will (how much more depends usually on the price tag of the header). So in your case, since you need to buy manifolds or headers no matter what, you just need to decide what you care most about and how much you wanna spend.
For me, I went cheaper headman headers. Sure they're not the best, but they flow pretty good for the time being and got me on the road for the last couple years. In the future I'll probably redo the exhaust and go with a nicer set of headers. But for now it's fine.
I totally understand your desire not to "booty fab" things together with this and you want to do it "right" the first time, but in my opinion, try not to get into the "might as well" mentality too much and start spending lots of money in places where it's not a big deal if you change it later on. Exhaust is one of the easiest things to change on a rig later on if you don't like it. With a project like this, I say you do what you need to do, to get the thing running and working. There will always be another year after its running of working out the kinks and changing a few things up to get it even more how you like it. Just my $0.02 is all
You pretty much nailed what my thoughts are. Just wanted to make sure I wasn't being "too cheap" or lazy with my thoughts.
I'm trying to find that sweet spot on getting rid of ghetto crap, and not getting too deep into MAW. I can get a set of manifolds from a vortec 454 for $50 from a texas yard. I've been leery on pulling the trigger for headers. I don't know if I want shorty/mid/long tube headers, and I just want to get this thing in and running. Maybe once I do a nice tune, I can go with a good set of headers to compliment it.
I went mid length headers. I personally like shorty or mid-lengths, but to each his own.
The other thing to consider is if you go with headers, you will need to move the driver side knock sensor into a different location with a different part number sensor (I believe somewhere in my crew cab thread I have that info in there). Headers on an 8.1 will hit the sensor/connector on the driver side knock sensor (passenger side is fine). If you go with a manifold, you won't have that problem (from my understanding). Just something else to consider
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There is only 1 o2 sensor on the 8.1's too, correct? If so, the vortec 454 manifolds are drilled and tapped for a sensor on the LH manifold, which is nice.
Mine has two O2's. One on each side
Won't a set of manifolds from a Vortec 454 have the wide spread at the collector like the 8.1? I know that the small block GMT400 manifolds are kicked out towards the frame.
The L29 vortec 454 manifolds also will have a spot for an EGR tube too (on the driver side). So if you use those, you will have to plug that up
I have no idea. I've never really messed with big blocks. @Kay86K5 might know.
My buddy has a set he's gonna give me off an L29 votec 454 from a late 90s sub. I might run them if they will fit cuz they will be free fifty free.
Well hurry and get yours on so we know if they fit lol.
Yeah that will not happen. Blazer is first and I'm having a hard time finding time to get anything done on it. Plus my cracked manifold doesn't bother me too much. Lol.
Worked in the driveway for a little bit last night before dinner was ready. Installed the new wheel wells and pulled the engine mounts after I took this picture.
Next on the list is cutting rivets and pulling the factory cross member. Then finish up a few things on the engine and drop it in this weekend. Once that’s done it gets pulled in the garage to start cleaning up more wiring.
Next on the list is cutting rivets and pulling the factory cross member. Then finish up a few things on the engine and drop it in this weekend. Once that’s done it gets pulled in the garage to start cleaning up more wiring.
I bought some cheap stainless headers off eBay and they haven’t given me any problem. I’m really impressed! I think the seller was speed daddy or something?
