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View Full Version : 1994 K1500 Vortec Heads + Cam Swap



dispoejoe95
04-05-2016, 06:58 AM
So I finally finished making some significant changes to my truck's engine. I'll admit that I intended to pay someone to program my ECM for me and honestly, I'm still not loaded with confidence that I can do it myself. But before I get to any of that, I need to get my truck running correctly. Just wondering if I need to do a basic flash program to match what I've done before I can start data logging and fine tuning? Right now when I hit WOT from a stand still, it hesitates and backfires through the throttle body. Seem to run ok under moderate acceleration or if I stand on it at 25-30 mph. Here is a list of the changes I've made.
Vortec heads
Roller Cam (GM #14097395)
-Duration 196/206
-Lift .431/.451
-LSA 109
GMPP Intake (GM #12496821)
TBI "Ultimate Mods"
EP377 Fuel Pump (Currently set at 22psi)
Hypertech Power Bowl
Shorty Headers
Upsized Y-pipe (2" to 2-1/4')
Eliminated catalytic convertor
3" Catback
Eliminated EGR

I've double checked the timing and I have it set at factory spec 0 degrees. I've seen some people say this cam wants to be retarded 4 deg. but I'm hesitant to do this. I've also read that that the close LSA on this cam will not run on the factory TBI programming at all. I'd sure appreciate any input you guys might have.
Thanks, Joe

dave w
04-05-2016, 07:53 AM
As a starting point I would use a stock Vortec 350 timing table. I posted the timing table for a 1998 Vortec 350 here: http://www.gearhead-efi.com/Fuel-Injection/showthread.php?1233-1998-Vortec-Timing-Table-%28Black-Box-Computer%29-Open-Closed-Throttle-ONLY!

As a starting point, you will likely need to add about 20% Acceleration Enrichment (AE) both TPS and MAP. I strongly recommend using a Wide Band O2 sensor to adjust both AE and Power Enrichment (PE). Here is a tread I posted for WBO2 tuning: http://www.gearhead-efi.com/Fuel-Injection/showthread.php?5381-Wide-Band-O2-%28WBO2-Tuning%29-Spreadsheet

dave w

dfarr67
04-07-2016, 12:20 AM
Not sure what ecu you have, mine is a 1990 with the 7747 unit. Might be worth while looking into this- need a laptop but can change things very easily and the Vender response is fast and knowledgable- search EBL on Thirdgen.org.

http://www.dynamicefi.com/

brian617
04-07-2016, 01:54 AM
That cam works just fine with TBI. The Vortec table Dave linked will help tremendously.

dispoejoe95
04-07-2016, 03:15 AM
Thanks for the info Dave. I will put this to use as soon as set myself up with some software and a programmer. Researching this now.

dispoejoe95
04-07-2016, 03:47 AM
Brian...I knew the cam will work with the TBI, my thought was this cam won't let it run well enough to start datalogging until I flashed a bin file that is closer to what I need. Thanks to Dave, I will be burning my first chip very soon.
DFARR67...I've just started looking into programmers. I have a 7427. Seems to make a difference as to what you can do and what software will work. Thanks for your input. Going to start another thread once I research Dynamic EFI and Moates a little further to see what has worked for other guys.

dave w
04-07-2016, 08:11 AM
The '7427 with the Moates.net Ostrich 2.0 is "ON PAR" with Dynamic EFI system.

dave w

dispoejoe95
04-19-2016, 08:15 PM
As a starting point I would use a stock Vortec 350 timing table. I posted the timing table for a 1998 Vortec 350 here: http://www.gearhead-efi.com/Fuel-Injection/showthread.php?1233-1998-Vortec-Timing-Table-%28Black-Box-Computer%29-Open-Closed-Throttle-ONLY!

dave w

Dave...sorry to have to ask but could you email me the vortec timing table? I try to view it or download it and it keeps opening and/or saving as .php file. I've screwed around with this for a while now and I can't get it to open in a legible format. My email address is dispojoe@hotmail.com.
Thanks.

dave w
04-19-2016, 09:52 PM
Dave...sorry to have to ask but could you email me the vortec timing table? I try to view it or download it and it keeps opening and/or saving as .php file. I've screwed around with this for a while now and I can't get it to open in a legible format. My email address is dispojoe@hotmail.com.
Thanks.

Are you using Mozilla Firefox for a Web Browser? https://www.mozilla.org/en-US/firefox/new/

Internet Explorer will save downloaded files as .php files. Mozilla Firefox WILL NOT save downloaded files as .php files. :thumbsup:

dave w

dispoejoe95
04-20-2016, 03:36 AM
That was the ticket....thanks Dave!