Thoughts on 4.8 / 5.3 internal upgrade

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Jul 8, 2005 | 11:12 AM

#11

white1

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From: Sittin on jackstands

Whats involved in building a 383 from a 5.3? Just droping in a 4" crank?

Jul 8, 2005 | 11:58 AM

#12

PappyDan

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From: Texas

Quote:

Originally Posted by ktmrider

The crank and rods are identical on the 5.3 and 6.0L motors, same part numbers. I verified this when I made my 383ci stroker from the 5.3 iron engine.
The max bore on the 5.3/4.8 block ( same bore size FYI ) is 3.905" and is what I bored it out to. I did a sonic check pre-post and the thinnest post area was 0.157" ( usual min thickness is 0.150" ). So, going the extra 0.100" or so for the 4" bore would be very dangerous IMHO. You could sleeve it but then are into the machine shop for some serious coin.

from 99 and up we have the LQ4 and the LQ9
the LQ9 is made with stronger parts then the LQ4.
the 5.3 runs the same crank and rods of witch 6.0?
just saying instead of going forged on the bottom end of a older 5.3 using LQ4 parts,
upgrade to the LQ9 crank and rods for the extra strength.

Jul 8, 2005 | 12:26 PM

#13

tdrumm

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Quote:

Originally Posted by PappyDan

From what I understand the cranks for a LM7, LQ4 & LQ9 are the same. A LM7 and LQ4 have the same rods. LQ9 rods are stronger than LM7 and LQ4 rods but can be swapped into a LM7 or LQ4 with no problems.

Jul 8, 2005 | 12:34 PM

#14

ktmrider

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From: Albuquerque, NM

Quote:

Originally Posted by white1

Whats involved in building a 383 from a 5.3? Just droping in a 4" crank?

Not quite, you do need to bore the block from 3.78" to 3.905". Once you do this tho, all the LS1 parts drop right in. The cost of the machine work was offset by what it would have cost to have some custom 3.78" pistons and rings made ( the stroker uses a different wrist pin offset so the stock pistons would not work ).
In all, I did save some money over buying a 6.0L but not a huge amount. I tell ya what tho, the extra stroke makes them serious torque monsters! Spins the tires on the 4x4 ECSB up here at altitude ( 5300ft ). Awesome.