454 swap into a half ton sub 4l60 living?

[Moofus02]

I've got a 99 suburban k1500. Got a 97 k2500 sclb 7.4 nv4500 373 gears. The sub has about 320k miles the truck 61k but bad frame. For the last 160k the sub had has low compression on a center cylinder on each bank. Did a leak down and all 4 center cylinders are leaking into crankcase and out exhaust and one out intake also. The one leaking all three ways takes about 30 seconds to start building pressure during leak down test but once it does it is only 15% the other three are 20 to 25% the end cylinders are about 3%
It blew a heater hose just after I got it and got hot. Had a miss ever since. 160k miles and I'm over it. I've got more 5.7's I could swap in but that L27 makes the most sense.
I don't work the truck. I drive 100 miles round trip to work 95 miles on the freeway. I pull a small trailer on occasion 4x8. Sometimes a car trailer to haul long stuff but not heavy.
I would love to swap the 7.4/nv4500 but the wife has a left leg prosthetic and can't drive a clutch. With gentle use what's the odds the 4l60e will survive.
If I do the swap I'll 0411 or p59 swap at the same time. I'll leave in the shift safteys. I also have 2 good spare transmissions. I've run 454 and 700r4 and had them live with gentle use.
I know 4l80 or nv4500 is the answer but I think I can make it live if the wife doesn't drive it often lol.

 

[L31MaxExpress]

Its either going to live a while and then smoke the clutches or smoke the clutches within a few days. Either way the 454 will destroy it eventually.

 

[Schurkey]

If you must, swap the engine. Get it to run good. THEN swap the computer.

That way, you'll know which is the problem when/if the thing doesn't run right after the swap(s).

A V6 can tear up a 700/4L60/'60E.

 

[L31MaxExpress]

If you must, swap the engine. Get it to run good. THEN swap the computer.

That way, you'll know which is the problem when/if the thing doesn't run right after the swap(s).

A V6 can tear up a 700/4L60/'60E.

I have seen a 3.0L 4 cylinder (Big brother to the 60s 2.5L Chevy II engine) break the input drum of a 700r4.

 

[Schurkey]

Got a 97 k2500 sclb 7.4...
...I've got more 5.7's I could swap in but that L27

L29?

I'm seeing L27 showing up as a Buick V6.

 

[99xcss4]

get a 4l80e or use the transmission that is all ready paired up with your 454

a 700r4/4l60/4l60e/4l65e/4/70e just wont do it

a sm465 or sm420 would also be okay

 

[Moofus02]

L29?

I'm seeing L27 showing up as a Buick V6.

Fat fingers on the phone lol

 

[Moofus02]

Looks like it's not worth the Hassel of a 383 or 454 without upgrading to a stick or 4l80

 

[99xcss4]

Looks like it's not worth the Hassel of a 383 or 454 without upgrading to a stick or 4l80

now hold on a minute here in the first post it says that the 454 has a nv4500 while I have never seen a manual in a gmt400 suburban and as far as I know none ever left the factory with one dose not mean that some things happened to get it done or maybe it was swaped in at some point but that would also be a great option imho

 

[Supercharged111]

Why not sell the NV4500 to fund a 4L80? Could even sell the existing 4L60 before it dies and is more worthless.