5.3L to 8.1L

[408.Luke]

On my buddys truck we had to modify one motor mount (passenger side)

[r.barn]

Hmmm, twin 76's on a 500 cubic inch motor .............. talk about over kill

Shooting for 1,700-2000rwhp ???? .......

I could figure out this surging crap. I already have a tire roasting set up, just surges in the upper rpms.

Have you done the math and plotted out your engine on the turbo's compressor
map to make sure you aren't bumping the "choke line" in upper rpms ?

Be happy to run the numbers if you dont know how. Takes about 2mins.

[GasGuzzler]

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. 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 never mentioned a taller frame. I said 2" body raise. The HD's (not the 99-2000 non-HD 2500's) have a 2" body raise regardless of frame channel height. I did not say the frame was altered to fit the Allison, I said the 2" body raise was. That is a fact. There were only a small handful (less than 100) 8100 Avalanches made, 2500 Avalanches are rare enough and 99% have a 6.0L. Either way, the 8100 Subs and Avalanches are all 2500's....and have a 2" body raise....as well as a different frame.

Mute point?

[DirtyLarry]

I never mentioned a taller frame. I said 2" body raise. The HD's (not the 99-2000 non-HD 2500's) have a 2" body raise regardless of frame channel height. I did not say the frame was altered to fit the Allison, I said the 2" body raise was. That is a fact. There were only a small handful (less than 100) 8100 Avalanches made, 2500 Avalanches are rare enough and 99% have a 6.0L. Either way, the 8100 Subs and Avalanches are all 2500's....and have a 2" body raise....as well as a different frame.

Mute point?

Well, you’re wrong. The HD’s do not have a “raised body”, they have a taller frame. That is why I mentioned the taller frame.

You are also wrong about the 8.1L Avalanches. All (yes, ALL) 2500 series GMT800 Avalanches had 8.1L’s and there were a hell of a lot more than “small handful” of them built between 2002 and 2006. The 6.0L was not available in the GMT800 2500 series Avalanches, although a 6.0L was the standard engine in the 2500 series GMT800 Suburban/Yukon and the 8.1L was an option. Both engines used a 4L80E.

Luke408 already summed this whole thing up with this picture. An 8.1L will fit at GMT800 halfton!

[zeake]

Well, you’re wrong. The HD’s do not have a “raised body”, they have a taller frame. That is why I mentioned the taller frame.

You are also wrong about the 8.1L Avalanches. All (yes, ALL) 2500 series GMT800 Avalanches had 8.1L’s and there were a hell of a lot more than “small handful” of them built between 2002 and 2006. The 6.0L was not available in the GMT800 2500 series Avalanches, although a 6.0L was the standard engine in the 2500 series GMT800 Suburban/Yukon and the 8.1L was an option. Both engines used a 4L80E.

Luke408 already summed this whole thing up with this picture. An 8.1L will fit at GMT800 halfton!

If he is wrong prove it, or stop messing up the OPs thread with useless banter.

[DirtyLarry]

I agree, I only came into this thread stating I saw no reason why an 8.1L wouldn’t fit in a GMT800 half ton as it appears many of you don’t have much information on the 8.1L. Your boy is the one that got way off track with incorrect useless banter.

I don’t need to prove anything to any of you. You can go do your own research if you don’t believe someone that works for the manufacturer and spend a great deal of time with the truck platform group.

[George C]

I agree, I only came into this thread stating I saw no reason why an 8.1L wouldn’t fit in a GMT800 half ton as it appears many of you don’t have much information on the 8.1L. Your boy is the one that got way off track with incorrect useless banter.

I don’t need to prove anything to any of you. You can go do your own research if you don’t believe someone that works for the manufacturer and spend a great deal of time with the truck platform group.

he also works for GM as a tech, in GasGuzzler's defense

[Mr.Cornelius]

I agree, I only came into this thread stating I saw no reason why an 8.1L wouldn’t fit in a GMT800 half ton as it appears many of you don’t have much information on the 8.1L. Your boy is the one that got way off track with incorrect useless banter.

I don’t need to prove anything to any of you. You can go do your own research if you don’t believe someone that works for the manufacturer and spend a great deal of time with the truck platform group

I'm sorry but I have to side with the person with almost 3,000 post vs. 6 posts...thats my proof...it just seems to me that you are a troll

[midevil1]

The guy with 6 posts is busy working for GMAC!

Some of us own shops and are busy building 1000hp, 2000hp, and yes 3000hp cars and trucks. I know I don't have time to put up 3000 posts. He doesn't know what he is talking about because of this???? You probably alienated someone with more knowledge than you will ever know.....

I don't know Gas Guzzler, but I know plenty of "TECHS" for the dealers that couldn't fit their finger in their A$$ with a funnel. Both of these guys seem to be sharp, but siding with one guy because he's got more posts is pure ignorance.

I happen to know of a 8.1L in a 01 rcsb with a whipple here in Houston running 11 flats on 22" rubber. Didn't look like any serious fab going on under the hood.

I don't have very many posts on all the diesel sites out there, but nobody argues with me when it comes to DMAX and CUMMINS. Daily driven 1200hp 2500TQ diesels coming and going from my shop help alot though.

My point being that everyone knows something you don't.........

[GasGuzzler]

Hahahaha.

Every one of the 2500 series Av's I've seen have had the U-code 6.0. I've seen one with an 8100 and was at the Vortec racing shop down the street and had an experimental VIN ending in "0000EXP".

I agree the frame is taller....but so are the body mounts. Otherwise, the floor wouldn't be any taller from the frame (needed to fit the Allison).

I also never said it would not fit, just that it would require some extra work.

Everyone calm down. LOL

I'll be the first to admit I know nothing.

midevil, I actually defended the BBC for you....