Engine swap poll

Engine preferences for engine swaps

  • Used 6.2L/used 6.5L

    Votes: 3 15.8%
  • New or rebuilt 6.5L

    Votes: 8 42.1%
  • Gasser swap- new crate motor

    Votes: 2 10.5%
  • Used gasser

    Votes: 4 21.1%
  • Build an engine

    Votes: 2 10.5%

  • Total voters
    19

ehuppert

Active member
197
34
28
Location
Upstate NY
I'm not sold on the LS, though recognize gains. My 1008 has a rebuilt gen 1 SBC. Mild cam, intake, headers. Work truck..... Hei needs one hot wire, no electronics other than that! (well, does have elec choke, so that's two wires!) Very simple

It's a nut and bolt restoration " work truck". Used for plowing, firewood and maybe 1500 miles a year...... Does everything I need it to do and early SBC parts are cheap! Had this one over 15 years.... The 82 C30 dually before this I had for over 20 years. Bought it with a blown 6.2 and swapped in a gasser!

Have a little experience in this arena! Used to be SBC's were cheap and available but not so much anymore. Then again, the newer vehicles start rusting before you drive off the lot.......

And I drove more miles then most in Cucvs when they were new...... And, have hearing loss to match those miles!
 

Skinny

Well-known member
1,858
91
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Location
Portsmouth, NH
I am not saying that old cast-iron small blocks are junk and maybe 15 years ago this would be a different conversation. I am just advocating that you can get a harness and motor mounts for under $1,000. You can make an entire swap fairly cheap these days.

15 years ago the aftermarket support wasn't what it is today and costs were way higher. But now finding one of these engines in a junkyard is a dime a dozen and I don't see why anybody would use that old technology when it costs pretty much the same today.

I get it if you are swapping a junkyard turbo setup or trying to do this on the super cheap. But trying to bring a CUCV into the modern era one piece at a time can be very expensive.

There is a reason why a 350 found a home in these trucks back in the day because that was the swap when the 6.2 was giving you trouble.

I wonder if this new LT engine that is out now will be something viable for cheap money in the future. This new 6.6 os making serious power. Although I'm sure electric will he a viable option too. Either way I'm burning tires with my 8.1 toll something as cheap can make 500 foot pounds 🤣

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Recovry4x4

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Is there as much aftermarket support for 8.1 swaps as there is for the 6.0 or 5.3. I've been watching these swaps on FB lately and some of these shrewd shoppers are doing the swap on the very cheap. For me, I wouldn't need a stage 3 cam (what the heck is that a 3/4 race cam from back in the day?), just a stock 6.0 would likely be perfect I think, 8.1 maybe better!
 

Skinny

Well-known member
1,858
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Location
Portsmouth, NH
The 8.1 uses the same motor mounts as the 454 so physically it occupies the same space and the exhaust bolts up to it.

Wiring is readily available for the same price. The 8.1 from an electronics standpoint is pretty much identical to an LS.

Two things hold you back. One is engine availability. They weren't produced for many years and only in select vehicles so they are limited in total numbers. That being said, you can find them anywhere and usually priced like an LQ4. They just aren't listed as much as the smaller engines. Parts are readily available as they share a lot with the 454 like starters and LS like sensors and actuators.

The second problem which is a critical one is AC. If you want or are going to want AC you need to source the Express Van bracket as it mounts the compressor up high. The pickup bracket will not work.

These are rare as hens teeth and fetch big money as you must have one to make AC work in pretty much any swap situation. I think GM made like 3 big block Express Vans. When I was shopping brackets fetched over $600 if you could find them. One junkyard actually said someone calls the minute an 8.1 van shows up on car parts looking to buy it. So someone out there is hunting these down. I'd guess it's Larry from Raylar. So if AC is in the mix then I'd suggest sourcing the bracket first or buy a motor from a van.

Aside from that, it's probably easier then an LS, makes basically a flat line torque curve which is bananas off idle, and is just as cheap to swap so it really is the unspoken secret if swaps. Unless you really need to work this thing the stock 8.1 is pretty ample in power. At no time am I like wanting more. Can't say that about a 5.3 or really any smaller engine. You have to wind the LS up to make power which the 8.1 does off idle.

Now when my 6.2 goes I really don't want to go through the bracket saga again. If I can't find one cheap again I'd probably go LQ4. Who knows, that junk probably will go 300,000 miles. By then it will be 2075 and I'll be hunting for diesel like Mad Max.



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Recovry4x4

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Thanks Skinny, since its a CUCV, A/C is a non issue. Back to your regularly scheduled program.
 

85CUCVtom

Member
719
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18
Location
Lakewood, Ohio
I have advocated this before and the cronies give me flack because of what I am saying.

If you have a CUCV and want some luxury like AC, overdrive, and maybe some more power, then the LS is by far the easiest way to get there.

For maybe $3k ballpark, you are into an LS which comes with a modern transmission and a compressor on the engine already. Plus a decent compressor and not that garbage pancake the 80's saw.

Ok maybe if you have a donor 80's truck with TBI that could come in at a lower price point but LS is a lot of upgrade for not a lot more money.

All the turbo, 6.5, or add ons are just not going to add up, be expensive one step at a time, and not really work well. A gear vendors is just a band aid on a junk TH400.

So let's go through it...

Add a turbo to 6.2
Repair a 30 something year old 6.2 with new IP
Add 4L80 or that Uber expensive Gear Vendors overdrive
Fit that awkward CUCV compressor bracket
Etc Etc Etc

So you are like three times as much money as an LS swap. Not to mention millions of LS 4L80 parts exist so you can have stuff on your door step immediately compared to 80's stuff. Don't shoot the messenger...

I have the original driveline in my M1031 but the minute that thing fails, I will have an LS shoe horned in there before any junk 6.5, although if you wanted stay diesel I guess you could go after a P400 or Optimizer but man those are big money.

My 8.1 Suburban drives like a muscle car and it was really the same price as a small block LS. The only downside is if you want AC you have to hunt for the unicorn van brackets to make it work. Aside from that and fuel economy I can't see why you would want anything from the 80's.

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Not to mention the LS is going to run great once tuned
Haha, yeah that will make the swap a lot cheaper.

I will say AC is awesome

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AC is awesome, I have it in my daily driver but I can sacrifice it in my 1009. The LS swap would be an ideal choice and admittedly I don't know as much about the LS line as I should but I do know when done right, they are super reliable and CAN get decent fuel milage. The LS series is all fuel injection correct?
 

Recovry4x4

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They make carb intakes for them if you prefer that route.
Not to mention the LS is going to run great once tuned


AC is awesome, I have it in my daily driver but I can sacrifice it in my 1009. The LS swap would be an ideal choice and admittedly I don't know as much about the LS line as I should but I do know when done right, they are super reliable and CAN get decent fuel milage. The LS series is all fuel injection correct?
 

Skinny

Well-known member
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Location
Portsmouth, NH
LS is all multipoint fuel injection. I don't know why you would go carb on it. They are also not heavily laden with emissions. Really simple and reliable.

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SuperAwesomeDOOD

New member
20
10
3
Location
Cool, CA
For the record, my 8.1 truck back in the day got about 11mpg. My 2019 Silverado 5.3 gets about 16.5 on 34” tires and 3.54 gears, but I rarely see a freeway—almost all rolling backroads. My CUCV with a vortec 5.7 and sniper EFI/timing control with a th400/3.73s got almost 15mpg. When complete with the nv4500 and Pro Flo 4 MPFI, I bet the CUCV will be on par with the new truck, albeit with less comfort and safety.

As far as power curves, the vortec 5.7 has more torque in the rpms most of us live and drive in than a 5.3/6.0 LS. So real world power and mpg is a toss up between those two trucks.

Honestly, if I wanted real grunt out of a CUCV that I didn’t put a ton of miles on and/or didn’t care about mpg—I’d do a 454 all day long. Far more support and potential. If I cared about mpg and/or didn’t need to tow much—it’d be a toss up between an LS and a Vortec 350 with EFI/timing control. I’d take an honest evaluation of my problem solving abilities and time to dedicate to the project. LS swaps can eat up time and budget if you aren’t great at bird dogging parts.

Not to mention, anything from a junkyard is a gamble. I’ve had a friend or two find a ‘low mile’ LS only to need a rebuild after getting it installed. But yeah, if you have the ability to swap a smaller LS and you throw a cam and a tune at it, it’ll make you smile a bit.
 
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