4.3 to 6.0 Swap Complete..Slooow

[George C]

if im not mistake the only difference between iron headed and aluminum headed 6.0s are just the heads correct..lol..

no, less aggresive cam, weak rods, bastard crankshaft, tad lower compression, heat holding iron heads.


yes you can swap out parts just like any of the gen 3 motors, yes youll gain performance but think of the ironhead 6.0 as the old TBI 350s. solid workhorses but not performers

[RichardLSX]

Alright, so internals are crap. I have a 4.56/Posi-Unit on the way, and might start on internals next.

[George C]

good luck with your build!!! im sure it will meet your expectations when your finished.

[RedHeartbeat]

a stall converter will wake it up, also. I'd run a 2600 stall in a stock LQ4.

[RichardLSX]

good luck with your build!!! im sure it will meet your expectations when your finished.

Much thanks!

[RichardLSX]

a stall converter will wake it up, also. I'd run a 2600 stall in a stock LQ4.

Yea stall should be good, maybe higher since I have the 80e. Now what I'm trying to figure out is if its worth it keeping this 6.0

[George C]

yea stall should be good maybe higher since i have the 80e..but now what im trying to figure out is if its worth it keeping this 6.0

that depends on what you truely want out of yoru truck. if you want big power the block is worht keeping and making a 408 out of it. if you want something to drive keep it in the truck and not worry. if you want the fastest 6.0 around then pull that sucker out and rebuild it with good parts. the answer all lies in what you truely want. Dont try to keep up with the Jonesys cause youll go broke

[RichardLSX]

Alright, well I was planning on tuning it tomorrow. But now I'm debating on whether going Flaco or Nelson. Who doesn't want to make lots of power! L0l

[badazzchevy327]

spray it lol. cool those iron heads down.

why not have some cheap fun go to a you pull it yard get a set of 5.3 heads. get a cam and some prc springs. swap it in, with your nelson tune and 4.10 gears and leave your friends scratching there head

[beertestr]

Before you go to the tune or parts swap route, answer a few more q's.

1) You said it goes like a bat outta hell when cold. This makes me think that you have an open loop-closed loop issue. When you motor is cold, and the ECT is below a certain threshold (which I need to look up for the exact temp), the engine runs on preset a/f ratios. When the engine gets warm enough, the engine looks at O2's, your MAF etc, and tries to correct for rich/lean conditions. This might be as simple as you have the left O2 plugged into the right bank and vice versa. I have found things like this more than I can count.

2) Are you sure you don't have any codes? Do you have the SES light wired up? Even if you do, not all codes are equal, there are many that do not trigger teh SES (check engine) light.

3) Do you have a scan tool? Drive the truck and look at parameters to make sure all your sensors are actually working. While an open or shorted circuit almost always triggers a code, a lazy sensor may not.

When you say you are not tuned, do you mean that the PCM in the truck is the 4.3L PCM or is the untuned 6.0L PCM that came with your motor? Hopefully it's at least the 6.0 PCM. Really, while the 6.0 you chose is not the strongest one you could have used, it should still be able to run a 4.3. And no your 3.42 ratio with a 3.73 cal will not cause all that degradation too. REally, your speedo, and what the PCM reads is off by 10%, that affects shift points a bit, but not alot.

Just some thoughts before you start plunking down cash on speed parts. You might be throwing money without know what the real issue is.