This is what I know. The headers are 1 3/4 primaries. They are installed. I don't intend to take them off. I would love a $1000 set of headers but I cant justify that. I have a BBP tune. It is installed. I don't have the money to go with another tuner even if I wanted to. Which I kind of do... me. I have no knowledge on how to tune a vehicle, yet. I have seen in this thread - BBP tunes soft, there's more left in the tune, Find a different tuner (I'm sure you have your reasons). What could I ask Justin specifically to do to get more bang out of this tune? Look guys and gals of PT.net I am still new to this and I really, and I mean REALLY appreciate y'all for posting and trying to help me out. I do intend on porting and polishing my 862 heads, Getting a nice cam and intake. And I definitely have plans on forced induction and forged internals but I have to take baby steps one at a time. Right now a retune costs me 15 bucks and P&P about 60. baby steps

 

Smokeshow You really seem to know your stuff. Do you tune professionally? If not, I think you could.

 

Could you explain to me your reasoning on why? Did you have a bad experience or...?

 

Honestly it has me questioning of all things the engine itself. It was supposed to be a stock replacement light duty L31 2-bolt main engine. I bought it from a GM dealer at wholesale pricing in an unmarked, open crate. Story goes it had been ordered for a customer that had a 4x4 Tahoe but backed out on the deal and went with a junkyard engine. It is a 880 casting with 5.7 stamped on the back near the bellhousing. I have been deep enough into it to know that atleast 3 important parts are not right for a by VIN replacement engine. It has 4-bolt mains, factory single roller chain and had a cam stamped with "395" rather than the "264" I would have expected. The stock tune was about 10-15% lean and back in the day I bumped the MFI spider to 70 psi to compensate for the lean running when I had the black box. This engine always felt like it had more torque than the stock engine but gave up quickly on top. Like I could step on the gas about 1/2 throttle and have more power at 3,000 rpm than WOT at 5,000 rpm. Where the stock engine had pulled strong to the 5,000 rpm shift points this one fell over at about 4,700 rpm. Right after I put the engine in I put a production LT4 cam and 1.6 rockers on it and the thing SCREAMED. I am thinking I may know where the extra 10% or so of airflow/airmass is coming from. Guess I need to pull the pan someday and check the crank casting number. With the way it pulls overdrive and tows I am almost thinking it is a 383 rather than a 350. HT383 torque would also help explain how it took out a 4L65E spec rebuild of the 4L60E in less than 40K miles. Would also explain the 8.5s demise.

 

I am sure if it is possible some datalogging would go a long way toward helping get your setup running better. 1 3/4" is better than the 1 7/8" I feared you were running.

 

Justin is a good tuner. the problem a mail order/street tuner/high volume tuner has is time and resources IMO. off idle/low rpm timing/afr needs to be measured in a way that the dyno/street tune will never work. dyno/street is great for WOT tuning from a roll. the track is where it matters. no street/high volume/dyno tuner will ever dial it down as good as someone who puts the time in with their own car on the drag strip where it matters.

 

Actually you can measure the low rpm/high load stuff, just need to drag around a heavy trailer in mixed driving to really load the engine. If it cannot sustain 50% or more throttle for a few miles at a time, towing uphill in hot weather its no good for me. If you are actually using the truck a trailer can heat soak the engine well beyond anything a 15 second or less 1/4 mile pass can do and really expose hiccups in your tune.

 

I knew I shouldn't have opened this thread.

 

I was talking about from a stop stomp like the op was referring to.

 

you know you enjoy this kind of postings




get to see fast355 talking out his *** on numerous things