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Help me decide - 8.1L or keep what I got

RootBreaker

RootBreaker

3/4 ton status
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Ok so I am nearing a decision...
I have a motor that runs very strong and rev limiter set to 5200rpms.
1991 caprice police hydraulic roller 350 ( L05 ) block
1996 Tahoe vortec heads
comp cams xtreme 4x4 roller cam .458" lift
full tube headers
weiand power plus+ dual plane vortec intake
holley truck avenger 670cfm aluminum carb (so much better than the old ones)
msd 6AL box with adjustable rev limiter
msd dizzy


so I don't wheel much anymore and when I do take the truck out, tired of it just not running right all the time. Sometimes it runs ok, others it runs great. I don't want to fiddle with a carb anymore...

so while I could throw a fuel injection setup on this... I found an 8.1L shipped to my door for $1300 and is in a running vehicle and guy is giving me motor with manifolds, computer, harness, fan shroud and airbox...

should I do it? I know others may say more options for LS swap but I'm not looking at buying aftermarket parts. So this will mount to my sm465... standard motor mounts.. other than needing to buy motor mounts and mount my clutch to it (think drill holes as I gotta re-read the 8.1L swap thread)... I should only have fuel pump and exhaust to do...

in the future when I am done with the truck, one of my kids will get it so it will be around and I think a 2002 8.1L isn't a bad thought...

what do you think? yay or nay...
 
^^^ u2 aint helpin... LOL...

just sounds cool to do an 8.1L.. someone say.. so u do an LS swap and you go.. Nope.. and they just give that dumb look.. hah..
 
Look at it this way, you do EFI and you don’t like it you can always resell it and the 350, or hell run it on the 8.1 and vastly simplify the swap.
 
Never been overly impressed with most aftermarket fuel injections setups I have seen. Maybe it was because they weren't installed right or tuned, but the guys were always messing with them trying to get them to run right. On the other hand I know several people that have swapped in a newer engine with factory fuel injection and they always run great with no problems. I think the 8.1L would be a great choice.
 
I'd stay away from the 8.1L. I had one last year that I was going to put into my K10 on 1 tons and 37's.

The one I had someone had cut and tig'd the oil pan. I wanted to get another stock oil pan to put on the but they're nowhere to be found.

The only performance upgrades/ aftermarket parts for the 8.1L are from one company... I forgot the name but they are pricey. They have heads, cams and such and they'll port the stock intake manifolds for the 8.1L.

I also hear of people having issues with the wiring with the 8.1L.

I was gonna run a carb on mine but the only company that makes a carb'd intake for the 8.1L charges around $650.00 for it.

Not knocking the engine by any means but your stuck with what the 8.1L has to offer in stock form unless you plan to drop big money.
 
handloader90 said:
I'd stay away from the 8.1L. I had one last year that I was going to put into my K10 on 1 tons and 37's.

The one I had someone had cut and tig'd the oil pan. I wanted to get another stock oil pan to put on the but they're nowhere to be found.

The only performance upgrades/ aftermarket parts for the 8.1L are from one company... I forgot the name but they are pricey. They have heads, cams and such and they'll port the stock intake manifolds for the 8.1L.

I also hear of people having issues with the wiring with the 8.1L.

I was gonna run a carb on mine but the only company that makes a carb'd intake for the 8.1L charges around $650.00 for it.

Not knocking the engine by any means but your stuck with what the 8.1L has to offer in stock form unless you plan to drop big money.
Click to expand...
I heard you don't need to drop a lot of money on parts, mainly just a tune to liberate the power available in the stock engine.
 
handloader90 said:
I'd stay away from the 8.1L. I had one last year that I was going to put into my K10 on 1 tons and 37's.

The one I had someone had cut and tig'd the oil pan. I wanted to get another stock oil pan to put on the but they're nowhere to be found.

The only performance upgrades/ aftermarket parts for the 8.1L are from one company... I forgot the name but they are pricey. They have heads, cams and such and they'll port the stock intake manifolds for the 8.1L.

I also hear of people having issues with the wiring with the 8.1L.

I was gonna run a carb on mine but the only company that makes a carb'd intake for the 8.1L charges around $650.00 for it.

Not knocking the engine by any means but your stuck with what the 8.1L has to offer in stock form unless you plan to drop big money.
Click to expand...


I have his 8.1. Is going into a 69 Buick Wildcat. Because LS swaps have been beat to death.
 
imiceman44 said:
I heard you don't need to drop a lot of money on parts, mainly just a tune to liberate the power available in the stock engine.
Click to expand...

The only point I was getting at with the 8.1 is that buying new stock parts for it (certain ones at least) seemed like a difficult task. I'm sure gaskets and pistons and such are available but oil pans sure are hard to come by.

And they seem to be a decent engine stock. They are 496 ci and I would expect more horsepower/torque than what they have stock.

And I hit up the aftermarket part because a lot of guys like to do things to their engines. SBC/BBC and LS have a ridiculous amount of aftermarket support. 8.1L's not so much.

I was planning on running a BBC 572 H.O. cam, carb intake and carb on that 8.1L before @ktmoutfront took it off my hands.

When you use the carb intake (pretty sure Dart makes it and they are the only one) you can run an HEI dizzy and the BBC can. I believe when you use the BBC cam it changes up the firing order so you have to pay attention to that.

And all I was really getting at is that an 8.1L wouldn't be MY first choice in an engine swap.
 
Also, the 8.1L shares the same motor mount holes as a SBC/BBC and same bellhousing pattern. Not sure if the oil pan would clear the engine crossmember but it should bolt-in otherwise
 
handloader90 said:
Also, the 8.1L shares the same motor mount holes as a SBC/BBC and same bellhousing pattern. Not sure if the oil pan would clear the engine crossmember but it should bolt-in otherwise
Click to expand...
I am not denying what you said, I never tried to find parts for it.
I am also confirming that it's a big engine and should have more power stock, and the reason it doesn't is the restrictions in the tuning to get better emissions.
When you reprogram it, you unleash the power, so no real need for all the typical upgrades older big blocks needed to produce more power.
I don't like to do much to engines to get more power, I just put a different engine that has more, in this case, if I find one that is reasonably priced I would get it.
 
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all of these are great reasons for yes and no... and that is interesting that some have owned it and say go for it and some own(ed) it and say no don't...

I don't like the aftermarket fuel injection idea cuz I cant walk into autozone and buy parts. I don't care about the massive HP... I need to find a place nearby with a dyno so can find out what is my motor putting out and in what power band. I love the thought of 400+ ft lb torque at 800rpms and I don't know where my power is. I can drop the clutch and spin my tires easily and no not in L.. in 1st (L-1-2-3)
 
I've got an LS swap. Now that my sled has gained the aerodynamics of a barn door, I find myself wishing for more power. Sure, it can be made with a turbo or blower on the high end, or more tuning, cam and other bolt ons. But no matter what I do it won't make power down below 2,000 rpm's like a big block would. I've experienced 8.1's first hand from my days with Workhorse and of course Larry's 8.1 powered rides.

There are pros and cons to the two. That horse has been beat to death time and time again. The 8.1 bolts in with NO adapters. The LS requires adapter mounts. Both benefit from having an ORD engine crossmember for clearance. The 8.1 runs the same PCM as the early LS so all the same tuning stuff comes into play. They have the same fuel pressure requirements. For all the physical size and mounting differences the 8.1L runs like a bigger brother to the LS family. Except the 8.1 has grunt way down low.

Larry's excellent resource thread explains it right down to the part number. As far as parts like the oil pan goes, yes GM discontinued it. But Spectra Premium sells a version through AutoZone, O'rielly's and other aftermarket sources that sell Spectra parts. The part number is GMP75A.

The thing that will make the swap harder to do moving forward is the lack of availability of the Workhorse accessory brackets that move the A/C compressor from down low on the block to like the Silverado/Sierra trucks use and put it up top and on the same belt as the rest of the accessory drive system. Talking to Larry about it there's an RV boneyard selling the brackets for a good chunk. But they can be had.

Yes the 8.1 is underrated. No less than the LS family is underrated stock and wake up with more performance oriented tuning. The 8.1 was built from the ground up to be a low rpm/high torque gas engine. From 3/4tons to medium duty and 24,000 pound GVW motorhomes. The stock tune is safe for a lifetime in an RV going up mountain passes just as easy a diesel pusher. I know this because I've driven them and passed the pushers going up I-70 west of Denver. In a K5 an 8.1 isn't even breaking a sweat. Add a basic tune to optimize the beast and it will make even more torque than stock and still do it down low in the rpm band.

I'll say this if I had a $1,300 running 8.1L available to me and actually had the money for it I'd jump all over it. I say that making the statement that I really do love having the 5.3 in my K5 as it is still superior to the original tbi 350 it came with from the factory.
 
^^^^ so ive read about moving the ac up high... can it be removed all together? I dont have ac and no need for the unit to be even moved...
 
ZooMad75 said:
Both benefit from having an ORD engine crossmember for clearance.
Click to expand...

so wait... are you saying you do not NEED to replace the engine crossmember as it is just a benefit or you do need too? ive been all over the thread. gotta readup more of it today. I put a list on it for me of ALL my questions and info and when I am done (yes I have decided to do it)... I will tweak it to be not a question guide but more of a - This is how I did it on a budget...

ZooMad75 said:
Larry's excellent resource thread explains it right down to the part number.
Click to expand...

yup all over that thread. guy hasn't pulled my motor nor is ready to ship it so Ive got time to keep reading and figure stuff out...

ZooMad75 said:
The thing that will make the swap harder to do moving forward is the lack of availability of the Workhorse accessory brackets that move the A/C compressor from down low on the block to like the Silverado/Sierra trucks use and put it up top and on the same belt as the rest of the accessory drive system. Talking to Larry about it there's an RV boneyard selling the brackets for a good chunk. But they can be had.
Click to expand...

I know I replied up a post asking you if you had too but figured as I'm replying to other parts of your reply, id add it here too...
 
Here's a built 350 next to a stock 8.1L. They make "the same power", but other than a $5k supercharger setup, no SBC can compare down low. Basically whatever the SBC/LS can do, the 8.1L does in the next higher gear. Torque and power are similar to early D-Max.

gm-8.1-v8-horsepower-torque-chart.jpg


12486041d_large.jpg
 
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