Joejamesatou

Honestly I don't. I had the two shops in direct contact. It is now a 5" aluminum driveshaft. And yes, 330whp works out 405 HP at the crank with 23% drive train loss, which is about what a 4L80E does. And that is with a dual 3 inch exhaust.

And the dyno brakes broke once a piece of the driveshaft hit it, and caused the rear tires to flat spot.

Tremek

Update: Shop says the driver side head has to come off if we want to pull the rear-most exhaust stud that's broken off.

If the heads are coming off... What should I do while they're off... LS7 lifters + lifter trays? Mill the 317s for higher compression?

Joejamesatou

I would spring for a set of 243 heads and enjoy the compression bump to 10.5 to 1.

FFDP

iTrader: (2)

Milling would be far cheaper and easier way to bump compression.

Joejamesatou

Finding a used set of 5.3 799/243 heads isn't expensive. At all.

FFDP

iTrader: (2)

Sure they won't cost an arm and a leg but $70-100 is still cheaper than $300-400 for a set of used heads.

Spending more money to get the same outcome isn't using common sense.

FFDP

iTrader: (2)

Re-think this a little.

If the trims are pulling fuel, even with them being -10 to -18, the computer is always aiming towards stoich. That is how narrow band sensor work. It doesn't matter what the o2 sensor fuel trims say, no matter the values it is trying to go back to stoich. Be it positive 12 or negative 8, it will always adjust towards the stoich value in the calibration.


If the trims were like that stock with good sensors, good fuel, non skewed alcohol content (on flex fuel vehicle), then there is likely poor working fuel injectors leaking in extra fuel. Maybe even a somehow the fuel pressure was over 58psi causing the injectors to spray more fuel.

Tremek

Found some used 317s locally for $150 and yesterday they came back from the machine shop with s clean bill of health. Screwed up though by ordering main ARP studs - not head studs - to get them back on the truck, so now waiting for Thursday delivery of head studs. Hoping to get the truck on the road by Friday!

Tremek

Finally got the truck back yesterday. It's running, but throwing some codes and the AFR looked very lean - idling in the high 15s, low 16s according to the gauge, and never dipping below mid-14s even under moderate throttle. Going to drive it a bit today and try and do some data logging, but ran into a peculiar problem I didn't anticipate -

I bought one of the new fancy AEM widebands that can talk directly to HPTuners via the CAN bus by passing through signaling over the OBD2 port. ...

That's all well and good, but to my surprise apparently my 2003 truck doesn't support CAN - only PWM/VPW? It looks as though GM may have started adding CAN as a supported protocol in 2004 for these trucks? Ridiculous...

So now I guess I need to figure out how to pass an old-fashioned analog signal to HPT? Unless there's some way to add or upgrade my truck to support CAN protocols... How odd.

In terms of break-in, I'm also trying to debate what's reasonable. I haven't gone over 4000rpm yet especially since I could see LTFTs up above 20% with the first tune PCM sent me - very concerned about going too lean.

With the new cam, refreshed heads and valvetrain, etc - how should I break it in? Thanks!

Joejamesatou

Being all roller it isn't nearly as important as it used to be back when you had flat tappet cams and lifters that had to mate. An oil changed after a few hundred miles as insurance in case there are any shavings that came off should do it. As to the tuning, ummm... good luck.