1991 K5 On/Off Road Use - Build 383 TBI for California Smog - Need Advice

All,
I am in the research phase of an engine rebuild/replace for the tired 350 in My K5 (I think it is the L05) I have ~250,000 miles on the original engine and it is sooooo tired, I just re-gear every other year or so.

Pictures of engine/smog included below.

My goal - get usable power down low with high(er) torque than the stock 350. This is for a 4x4 that will see dirt, rock crawling, and a bit of street miles with the occasional overland/expedition trips. On the expedition trips it will be towing a small utility trailer (1/4T Military). It will not see the following: high RPM for long periods of time, the dragstrip, or smokey burnouts :)

1. TBI how/where to start with programs, tuning, etc....
   
   
   • Can I tune the new (383 detail in item 2) adequately and still pass smog?
   • I have another complete TBI setup - build that to better serve the 383 requirements?
   • Please point me to the 'how to tune your TBI' tutorials (software, datalogging). I am PC literate and I have done tunes with systems for Motorcycles, LS's etc… While I understand the components, variables to tune, and data in general I am a NEWB to any TBI technology. (I have had the K5 since 93 and the TBI is like Gump - it just keeps running….). I am looking at the WinALDL stuff already - need to make a cable if this is the best/latest.
     
   
   
   
2. Confirm long-block build as likely to pass with good TBI tune, hoping to start with the HT383e http://www.chevrolet.com/performance...k-ht-383e.html
   
   
   • Will this be a good starting point or will that cam destroy my catalytic converter?
   • My requirements for the new engine - more usable power down low. This will rarely see high RPM.
   
   
   
3. What exhaust manifolds should I plan on using?
   
   
   • Is there an OEM set I should search for?
   • Is there a CARB set available or will that draw too much attention, legal or not? Something like the Tri-Y for torque - I am not crazy about headers but I hear the stock manifolds on this 350 are very restrictive.
   
   
   
4. Anything else I should look at?

Vehicle:
1991 K5 - originally sold in Texas (minimal smog equipment: no air pump, plumbing, etc…)

• It has 2 into 1 exhaust before the single cat
• Engine - stock everything
• 4L60 transmission (not 4L60E)
• Gear ratio will be based on 5.13s with 37" tires
• Weight ~7200lb - includes fuel, recovery gear, etc….

Thanks,
Dave

First off, every bit of smog equipment that is on there will have to be saved and reused. Be aware that the HT383 heads may not have EGR provisions which will be a deal breaker. EGR must work! If all your smog equipment works, it will pass the visual inspection fine since a 350 block is what the 383 is built from. It will take some time tuning it, I would use TunerproRT to datalog, but you will need to burn a chip to start unless you can find one someone with the same setup used. Be aware that if will be smogged on a dyno, so your tune will need to be spot on. Good luck They do make CARB headers, thorley triys are the best.

PS I also live in Calif. so I am aware of what you need to do.

Quote:

---

Originally Posted by jim_in_dorris

First off, every bit of smog equipment that is on there will have to be saved and reused. Be aware that the HT383 heads may not have EGR provisions which will be a deal breaker. EGR must work! If all your smog equipment works, it will pass the visual inspection fine since a 350 block is what the 383 is built from. It will take some time tuning it, I would use TunerproRT to datalog, but you will need to burn a chip to start unless you can find one someone with the same setup used. Be aware that if will be smogged on a dyno, so your tune will need to be spot on. Good luck They do make CARB headers, thorley triys are the best.

PS I also live in Calif. so I am aware of what you need to do.

---

Thanks Jim!

Bummer on the HT383 heads.... I will confirm EFR/no EGR function.

I do not live in a dyno County, I guess I have 1 good thing going there.

I will check out the TunerproRT and start looking for a chip programmer.