I've heard the same thing about limited aftermarket support for the 8.1L, but that depends on what your plans are for the engine and if you think you need more than the factory 330 HP and 450 ft-lbs. of torque...which is generally a fairly big upgrade from what you are replacing, not to mention the smooth and consistent running. Two guys in my club have 8.1L tow rigs (one a 2500HD and the other a Suburban). I have an 6.0L 2500HD and will say that the 8.1L rigs will eat my lunch when towing. The one guy had headers and a dyno tune performed on his 2500HD and it made a noticable difference also. Point being if you went with a truck 6.0L swap you have a lot more aftermarket support, but you would need it to get the same power numbers as you would with a stock 8.1L. To also keep things in perspective a buddy built an old Ford 460 big-block years ago and in order to get the same power numbers as the stock 8.1L it required heads (basically a higher compression and performance factory version with some work), cam, full length headers, and carb work to get there. That engine did run great and would really spin a set of 42's.
CK5
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Help me decide - 8.1L or keep what I got
- Thread starter RootBreaker
- Start date
FiTech uses factory sensors and injectors so that wouldn't be a problem.
I feel like my video should explain some things for the OP pretty well. I tried to go into some detail of the swaps in the video. To summarize, yes you need the ORD big block engine cross-member as the 8.1 will hit your factory cross-member. It's a nice piece, and really not that bad of a price considering. You can use your stock motor mounts in your truck right now, but to be honest, just upgrade them now as I'm sure the 8.1 will chew through an already used stock motor mount. Since you have a 350 in your truck now, just get either ORD's or DIY's competition poly motor mounts for a small block. They will bolt up to the 8.1 just fine and last a long time (and no, they don't have noticeable vibration, at least from what I can tell). I talk about cooling in my video, and talk about fueling, but that has been beat to death as fueling is pretty much the exact same as any other LS swap. To bolt to your SM465 just get an 8.1 specific flywheel (can be picked up anywhere) and your current clutch pack will bolt to the flywheel. You may have to drill out the little mounting holes on the clutch pack a tiny bit as the 8.1 flywheel bolts are metric and just a smidge larger...literally, not a big deal. The stock 8.1 exhaust manifolds will hit your frame, but just get some older 454 manifolds or headers and they bolt up no problem with no real frame clearance problems. Any other smaller detail is outlined in Larry's thread very well and is a great source.
I have always said, if you want to build a BBC, do not go with an 8.1 as yes, the aftermarket is limited which means its expensive. There is stuff out there to build them how you want, but it costs buku bucks. If you are going to build one, just get a 454 as the aftermarket is extensive and about half the price to attain the same desired numbers. But, if you want a simple, good, reliable BBC, an 8.1 is a fantastic option. And yes, in stock form the tune is chocked down quite a bit. A simple tune can get you ~400hp and 500ft lbs...and that is doing nothing to the motor other than tune. For most people's uses, that is plenty and will suit their needs. It's not the perfect solution for really anyone, but I think people are starting to realize that its a fantastic BBC option to get the smoothness/reliability of LS (though it's not really any LS motor), but have found out it's almost easier to swap into some older trucks like our square bodies than 5.3/6.0's (plus the added numbers in stock form too).
To each their own...some people love to hate on the 8.1, some people love it. Just figure out what you want out of your truck and then tell everyone else to suck it
. Though I got a lot of crap from people saying I shouldn't do an 8.1 in my CCLB...now that it's running...everyone wants to buy it off me now...funny how that works 
I feel like my video should explain some things for the OP pretty well. I tried to go into some detail of the swaps in the video. To summarize, yes you need the ORD big block engine cross-member as the 8.1 will hit your factory cross-member. It's a nice piece, and really not that bad of a price considering. You can use your stock motor mounts in your truck right now, but to be honest, just upgrade them now as I'm sure the 8.1 will chew through an already used stock motor mount. Since you have a 350 in your truck now, just get either ORD's or DIY's competition poly motor mounts for a small block. They will bolt up to the 8.1 just fine and last a long time (and no, they don't have noticeable vibration, at least from what I can tell). I talk about cooling in my video, and talk about fueling, but that has been beat to death as fueling is pretty much the exact same as any other LS swap. To bolt to your SM465 just get an 8.1 specific flywheel (can be picked up anywhere) and your current clutch pack will bolt to the flywheel. You may have to drill out the little mounting holes on the clutch pack a tiny bit as the 8.1 flywheel bolts are metric and just a smidge larger...literally, not a big deal. The stock 8.1 exhaust manifolds will hit your frame, but just get some older 454 manifolds or headers and they bolt up no problem with no real frame clearance problems. Any other smaller detail is outlined in Larry's thread very well and is a great source.
I have always said, if you want to build a BBC, do not go with an 8.1 as yes, the aftermarket is limited which means its expensive. There is stuff out there to build them how you want, but it costs buku bucks. If you are going to build one, just get a 454 as the aftermarket is extensive and about half the price to attain the same desired numbers. But, if you want a simple, good, reliable BBC, an 8.1 is a fantastic option. And yes, in stock form the tune is chocked down quite a bit. A simple tune can get you ~400hp and 500ft lbs...and that is doing nothing to the motor other than tune. For most people's uses, that is plenty and will suit their needs. It's not the perfect solution for really anyone, but I think people are starting to realize that its a fantastic BBC option to get the smoothness/reliability of LS (though it's not really any LS motor), but have found out it's almost easier to swap into some older trucks like our square bodies than 5.3/6.0's (plus the added numbers in stock form too).
To each their own...some people love to hate on the 8.1, some people love it. Just figure out what you want out of your truck and then tell everyone else to suck it
sweet... hah thx
fuel pump... so you used hose clamps on the tank side and it will hold with the pressure...hmmm
-6an fittings - noted...
No, I ended up cutting the ends of the ends of the sending unit (where you normally attach the hose and clamp) and flared the lines with a flare nut on it. Then bought little adapters to bolt to those flare nuts that converted both supply and return to -6AN, then just bolted my -6AN lines and hose ends I built to that. Somewhere in my build thread I list links to all the little parts I used to do it. I know earlier in the thread its hard to go through cause photobucket sucks, but if you just search on each page, you will see where I included links to everything I purchased for it
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Actually, as I looked back, I think all I showed were pictures which are now gone...so here you go, here are links to the items I bought (like I said, used factory TBI sending unit, and cut off the little ends where you normally had the hose clamp on, the flared the lines using these on feed/return):
Return line at sender:
https://www.summitracing.com/parts/EAR-581805ERL
https://www.summitracing.com/parts/EAR-581905ERL
Feed line at sender:
https://www.summitracing.com/parts/RUS-660571
https://www.summitracing.com/parts/RUS-660651
Return Line adapter to bolt to tube nut:
https://www.summitracing.com/parts/AER-FBM2755
Feed Line adapter to bolt to tube nut:
https://www.summitracing.com/parts/EAR-981506ERL
Then these are the normal hose ends that will attach to the flexible braided fuel lines, and then bolt to the adapters at the sender:
https://www.summitracing.com/parts/RUS-610025
Then you just need to buy enough length of flexible braided hose, and run it up and back to the motor. In the middle of the feed line I cut it in half and then just added a little aftermarket fuel filter that already had -6AN ends on it from summit too. I think the little filter was only $30 or so.
There are other ways to go about the fuel lines (and some other ways may be cheaper), but to be honest I love that I did it this way cause then I could run the lines wherever I wanted to keep it away from exhaust and make it easy to do repairs if need be, so I think it was worth it.
So there you go
Vombrown
Mountain Man
I feel like my video should explain some things for the OP pretty well. I tried to go into some detail of the swaps in the video. To summarize, yes you need the ORD big block engine cross-member as the 8.1 will hit your factory cross-member. It's a nice piece, and really not that bad of a price considering. You can use your stock motor mounts in your truck right now, but to be honest, just upgrade them now as I'm sure the 8.1 will chew through an already used stock motor mount. Since you have a 350 in your truck now, just get either ORD's or DIY's competition poly motor mounts for a small block. They will bolt up to the 8.1 just fine and last a long time (and no, they don't have noticeable vibration, at least from what I can tell). I talk about cooling in my video, and talk about fueling, but that has been beat to death as fueling is pretty much the exact same as any other LS swap. To bolt to your SM465 just get an 8.1 specific flywheel (can be picked up anywhere) and your current clutch pack will bolt to the flywheel. You may have to drill out the little mounting holes on the clutch pack a tiny bit as the 8.1 flywheel bolts are metric and just a smidge larger...literally, not a big deal. The stock 8.1 exhaust manifolds will hit your frame, but just get some older 454 manifolds or headers and they bolt up no problem with no real frame clearance problems. Any other smaller detail is outlined in Larry's thread very well and is a great source.
I have always said, if you want to build a BBC, do not go with an 8.1 as yes, the aftermarket is limited which means its expensive. There is stuff out there to build them how you want, but it costs buku bucks. If you are going to build one, just get a 454 as the aftermarket is extensive and about half the price to attain the same desired numbers. But, if you want a simple, good, reliable BBC, an 8.1 is a fantastic option. And yes, in stock form the tune is chocked down quite a bit. A simple tune can get you ~400hp and 500ft lbs...and that is doing nothing to the motor other than tune. For most people's uses, that is plenty and will suit their needs. It's not the perfect solution for really anyone, but I think people are starting to realize that its a fantastic BBC option to get the smoothness/reliability of LS (though it's not really any LS motor), but have found out it's almost easier to swap into some older trucks like our square bodies than 5.3/6.0's (plus the added numbers in stock form too).
To each their own...some people love to hate on the 8.1, some people love it. Just figure out what you want out of your truck and then tell everyone else to suck it
Ain't that the truth. You need to decide what your needs are and what you want. If the swap is worth it to you then go for it! I'm a diesel guy but I wanted to build a gas burner this time and went a long winding road to come right back to a mildly built 454. I bought an LS engine to use and was going to do it until I got to drive one on the road in my area and conditions. That was a HUGE game changer for me. I would make the suggestion that you do the same. Even if it means driving a few hours to do it. Find someone that has the setup you want to do....go visit and take it for a spin. At least go for a ride in it. You'll learn more in ten minutes than you will in ten days of forum posts. For me after driving the LS swapped one ton I knew immediately it wasn't what I wanted. You may be just the opposite.
Actually, as I looked back, I think all I showed were pictures which are now gone...so here you go, here are links to the items I bought (like I said, used factory TBI sending unit, and cut off the little ends where you normally had the hose clamp on, the flared the lines using these on feed/return):
Return line at sender:
https://www.summitracing.com/parts/EAR-581805ERL
https://www.summitracing.com/parts/EAR-581905ERL
Feed line at sender:
https://www.summitracing.com/parts/RUS-660571
https://www.summitracing.com/parts/RUS-660651
Return Line adapter to bolt to tube nut:
https://www.summitracing.com/parts/AER-FBM2755
Feed Line adapter to bolt to tube nut:
https://www.summitracing.com/parts/EAR-981506ERL
Then these are the normal hose ends that will attach to the flexible braided fuel lines, and then bolt to the adapters at the sender:
https://www.summitracing.com/parts/RUS-610025
Then you just need to buy enough length of flexible braided hose, and run it up and back to the motor. In the middle of the feed line I cut it in half and then just added a little aftermarket fuel filter that already had -6AN ends on it from summit too. I think the little filter was only $30 or so.
There are other ways to go about the fuel lines (and some other ways may be cheaper), but to be honest I love that I did it this way cause then I could run the lines wherever I wanted to keep it away from exhaust and make it easy to do repairs if need be, so I think it was worth it.
So there you go
thx for that...
scratch this comment.. very expensive!!!! $130 x 2 for supply... no way.. ill figure something out...
{ I'm planning on using what Larry pointed too for part numbers for fuel lines on feed and return back from motor as far back as I can... stock workhorse lines; however, I am expecting to possibly do what you did with the connectors}}
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I think you will find, no matter which way you go with these types of swaps...its gonna be expensive. It's just the way it is. I love when people say, "Just LS swap it! You can pick up a motor for less than a grand and your good to go!" Bahaha. Never works out that way. Stuff nickel and dimes you. But gotta pay if you wanna play (with cool stuff that is)
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I'm the king of cheaper.. so I get you.. and some I don't mind paying when expected... but at times there are no reasons to do somethings that aren't needed. we always spend...
so I'm looking at
$1300 motor shipped
$60 motor mounts
$200 cross member
$200 fuel lines
$xxxx exhaust -dunno yet
$xxxx tune - dunno local cost yet
I think my clutch stuff will work on my 1991 motor as I think I read you need an internal balanced flywheel and I think mine is.. so shouldn't need much for clutch side...
No matter what you need an 8.1 specific flywheel, other than that everything else you have clutch wise should work. You planning on running DBW throttle, or cable setup like Larry?
Since the truck a/c compressor runs on its own belt you'd be fine running the stock truck accessories for the water pump, crossover, ps and alternator. That would save some coin for sure.
^ What he said. That's what is currently in my truck is just normal truck accessory brackets. You just remove the A/C compressor, mount and belt for the compressor (A/C is run on it's own separate belt from the serpentine belt) and you are good to go to run the motor and not worry about A/C. I do have a full set of Workhorse stuff in my shop though that I will eventually swap onto my 8.1 (brackets, water pump, crossover tube, crank pulley...literally everything), but I wanted to get the truck running and driving first...then swap later.
Didnt notice that. Wow as i havent seen one in person. 8.1L is like a legend to me but eventually ill be sleeping with one.. i mean installing..
Thx.. so i cant find it while on my phone.. i thought in the resource thread i read larry say you can use a 1991 manual flywheel but most likely need to drill bolt holes a little as 8.1 bolts are metric. When i get home i gotta find that.
Just found this by google searching and hit a pirate4x4 link and this guy says the same except pins...
79rustyk10
3/4 ton status
I think the 8.1 is the only way to go as far as swaps go. Get the modern injection, and reliability, with the dump truck loads of low end torque. At that price, I'd already have it in my garage.
There is literally no downfall to this swap.
There is literally no downfall to this swap.
runamok151
1 ton status
8.1 and an Allison would be sweet in your truck.
