4.3 to 6.0 Swap Complete..Slooow

A while back you all help me out on how to do a swap on my 99 chevy silverado single cab V6. I swapped in a 2000 6.0 with a 4l80e tranny, wiring harness and even the steering column.

NOTE: Truck Is Not TUNED it wasn't necessary since I swapped steering columns

NOTE: My truck has 3.42s and I know the PCM is programmed for 3.73s Could this be the problem??????

What i wanted to know is why would my truck be so slow.
Iv'e been told it needs a tune. "which I should be getting tomorrow BTW"
But mildly modded 4.8s still beat me :lol:
Iv'e been beat by mild 4.8s, almost bone stock 5.3s and even 4.3s seem to keep up on 20 rolls. :sigh:
Its hard to explain how embarrasing and depressing it feels to have wasted 3k+ and still be one of the slowest. LMAO

But on a serious note, any suggestions?

It's probably lean. Get the tune. They run richer cold.

lets see, you have a ironhead 6.0, your using a stock PCM for one which isnt peformance computer. most 3/4 ton trucks are absolute pigs. wrong gearing will have a small effect but only on shifts

So basically, tune and it'll be good to go?

Quote:

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Originally Posted by Richard4.3

so like everyone has been telling me..its the tune that i need?

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not to mention the motor you have. the ironhead 6.0 isnt a strong motor they lack the HP/tq the aluminum head motors do

So I'm basically screwed with that motor or is it still better than a 5.3. Also 4.8 or 5.3 aluminum heads should work correct?

And the 80E trannie uses a bit more power than the 60e you were racing. Get it tuned and go from there. A good stall will get that truck moving as well.

Quote:

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Originally Posted by Richard4.3

so im basically screwed with that motor or is it still better than a 5.3..also 4.8 or 5.3 alumn head should work correct?

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its up to you. i think the ironheads are only 295 or 300. a 5.3 is 285 for the older ones and have a better cam in them with decent flowign heads.

for now just get a proper tune

Could he just swap to 317 heads, or even better?

Quote:

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Originally Posted by Quik

its up to you. i think the ironheads are only 295 or 300. a 5.3 is 285 for the older ones and have a better cam in them with decent flowign heads.

for now just get a proper tune

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If I'm not mistaken, the only difference between iron headed and aluminum headed 6.0s is just the heads correct..lol..