5.3L to 8.1L

[RedHeartbeat]

I would look at it in the perspective of future profits. How many small block to big block conversions do you think people will be doing? Are you going to be gaining customer sales on such a miniscule niche market? Why not work on a setup for a more popular vehicle like 73-87 or 88-98 1/2 ton 2wd chassis trucks with the LSx based engine conversion? Make it a bolt in kit for those that don't have fabrication skills or access to a welder.

[GasGuzzler]

There is hardly a mileage difference between a 6.0L 2500 and an 8100 2500 stock because the 6.0L has to work so much harder to do the same work....and the 8100 has a 5-speed auto (or six speed manual).

The 8100's all get horrible mileage but so does a stock LQ4 in a 2500 truck pulling loads. The 8100 didn't make the cut because it didn't sell. It didn't sell because it cost a little more to operate than a 6.0L but a lot more on the sticker (mostly because it was extra cost and the 6.0L was standard)....and although a lot less than a diesel on the sticker and operating cost, it was still too much money when compared to the capability of the Duramax.

It's not a bad engine at all....it's just really large by external dimension, very heavy being almost all iron, gets poor mileage (bad excuse not to use one), and has hardly any aftermarket support because of its relative rarity. Vicious cycle...

[Trick1]

Man yall are thinking way to hard on this.LOL
The reason to it is
because its there.
Not for profit, not for gasmilage, not even for power.
Just wanted to see if we can.
We already can kill the tires @ 45mph.

TrickPerformanceProducts, builds alot more 1 off type pieces for customers then we do mass production stuff. Sure the electronic are mass produced, and the turbo its are somewhat mass produced. But any really laid outfab work is usually limited to a handfull of customers, and the really wild stuff is limited to even less.
Thats ok with us, it allows us the opportunity to build what our customers want and to always be working on something a little different.
Mass production stuff is boring to me, did it for almost 9 years @ a nitrous company.
I strongly believe if someone is looking for gasmilage they should have never bought a truck. I have a daily driver that makes pretty good gas and is the all around parts getter. This is a test truck to test new things, new ideas, and different ways to do things. It is used a bunch in the electronic development of our products. back on track.

I hope to be at the dyno this week with the 5.3 and then I can pull it out and start shoe horning this monster in.

[Trick1]

OH on side note, If we had a kit that gave you 700-900whp that would be a bolt in that would be cool too.

[xXxSilveradoxXx]

This all reminds me of my build. 1998 Vortec 454 into a 1989 K-1500

LINK

[Kamikazekyle05]

any updates on this, this will an awesome swap!

[Trick1]

Nothing new, we had to figure out what was wrong with the 5.3 first. thought is was electrical and did not want to have a new set up with an old electrical problem. Probably start tearing the 5.3 out within a week. Had to get back to work on some big projects we have been waiting on parts for.

[DirtyLarry]

to fit 8.1 youll need the front frame clip since the rails are shaped differently. wouldnt be a direct swap. best to start with a 3/4 ton 2wd truck

anything can work if bust out the torches and welders

I don't understand why would you need to do any frame work to fit an 8.1L in a GMT800 half-ton 2wd? The 8.1L has the same mounting as the old 7.4L, 5.7L and 4.3L V6. Being the 4.3L was an option in the GMT800, I don’t see why it wouldn’t bolt right in.

If you are thinking the A/C compressor would contact the frame, it just might. Just use GM medium duty truck, 2000-2002 3500HD or Workhorse Custom Chassis accessory brackets and move the A/C compressor to the driver’s side top of the engine and alternator to the passenger’s side similar to the L29 7.4L brackets. Same with exhaust manifolds. Any BBC exhaust manifold will fit the 8.1L. You would think one of them would fit the frame if the original 8.1L manifolds posed an issue in a halfton.

I dropped a 2002 8.1L into a 1978 K10 a while back and was surprised how easy it actually was. Used the same engine mounts, clutch and pressure plate from the 454HO that was removed as well as exhaust manifolds although I did use a specific 8.1L flywheel. The 8.1L is pretty much a direct bolt in. Mine is running on a Delphi MEFI-4 engine controller similar to the RamJet engines and marine engines. I may change it over to a MAF system sometime but so far I am happy with the speed density MEFI-4 system as it a much less intrusive wiring harness to deal with. This ’78 running a MEFI-4 controller on a custom calibration would run circles around the 454HO it replaced and definitley has a lot more nut than my stock 2001 Silverado 2500HD with an 8.1L.




A few YouTubes.
YouTube - Dirty Engine

YouTube - 8.1L mild launch

YouTube - Westcliff Stuck again

Install pictures is my sig.

[GasGuzzler]

I bet it would fit but a 900 didn't come with a 7.4 or an old school 5.7 either. The factory 8100 trucks have a 2" body raise over a half ton....and the frame is different. Just need some custom engineering. The 73-87 bodies did come with 454's in half ton form in the 70's.

[DirtyLarry]

I bet it would fit but a 900 didn't come with a 7.4 or an old school 5.7 either. The factory 8100 trucks have a 2" body raise over a half ton....and the frame is different. Just need some custom engineering. The 73-87 bodies did come with 454's in half ton form in the 70's.

I was a sales technical liaison to the Silverado/Sierra Brand Teams in 1998 during the launch of the GMT800’s so I am well aware the GMT800’s did not come with a 5.7L or 7.4L although they did come with 4.3L V6’s. My point is the 4.3L has common engine mounting as the 5.7 and 7.4L (6.5L diesel too), which is exactly the mounting the 8.1L uses.

While the HD frame is different from a LD frame, as it has a much taller frame channel to achieve a higher section modulus for increased GVWR. The taller frame was used for added strength to the hydroformed frame rails and contrary to popular belief, was not designed taller for the Allison, although it does help with fitment.

Regardless, HD or LH frame, I still see no reason why an 8.1L won’t fit in a GMT800 or even GMT900 half ton. Look at the GMT800 Suburban and Avalanche. They came with 8.1L and the Suburban/Ave frame has more in common (channel height) with a halfton frame than a HD frame so the taller frame to fit a 8.1L is a mute point. I would be curious to see the article on the truck in post #8 where someone said the orange halfton truck had a body swap.