1994 TBI Truck ZZ2 Swap

**portmod7** · 07-20-2023

I bought a 1994 C1500 as a project. It's all stock. I have a ZZ2 crate that I was considering swapping in to replace the 200k mile 5.7 that's in it. My intent was to get a Holley 502-9 and crank the fuel pressure up to handle the 350HP the motor is rated for. However, in my research, I came upon some opinions that the ZZ2 might not be friendly to TBI, mostly because of the cam in it. I was wondering if anybody here had some insight? Would I be wasting my time, energy, and money?

10134334 Hyd. Roller 235/235 .480"/.480" 9.0:1 114

The other part of my question, I would be "street tuning". I.E. Datalogging while driving and tweaking the tune over time to try and dial it in, or using the EBL system, or something like that. How GOOD do those tunes really get?

I have a C10 with a ZZ4 running on Megasquirt with a FAST throttle body, Ford EDIS crank trigger, and it took a LONG time and a lot of learning to get that thing decent. It's not even close to a factory tune. I would really like my C1500 to behave like a factory tune. Startup, warmup, stop and go traffic, etc.

Thanks!

**dave w** · 07-20-2023

Using an AFR meter will be very helpful during the tuning process.

Link to AFR (WBO2) Tuning Spreadsheet: http://www.gearhead-efi.com/Fuel-Inj...ng-Spreadsheet

The TBI Timing Tables are not optimal. Possibly OBD2 Vortec timing tables will be a good place to start? Link to Vortec Timing Table: http://www.gearhead-efi.com/Fuel-Inj...-Throttle-ONLY!

**portmod7** · 07-20-2023

Originally Posted by dave w

Using an AFR meter will be very helpful during the tuning process.

Link to AFR (WBO2) Tuning Spreadsheet: http://www.gearhead-efi.com/Fuel-Inj...ng-Spreadsheet

The TBI Timing Tables are not optimal. Possibly OBD2 Vortec timing tables will be a good place to start? Link to Vortec Timing Table: http://www.gearhead-efi.com/Fuel-Inj...-Throttle-ONLY!

Thanks!

I was figuring on doing a wideband controller and input into whatever I end up doing for the ECU, if possible. So much figuring out to do!

I'm also really tempted to just 6.0 LS swap it to be able to run a GM calibration. Trying to dial in my Megasquirt was not the most fun I've ever had.

**dave w** · 07-21-2023

The only easy tune is completely stock (not much fun to drive) TBI engine. Anything fun to drive (TBI or otherwise) requires additional money and additional work

**FirstGenThree** · 07-21-2023

I haven't pushed the tbi limits with regard to cam duration but that does seem like you could have some tuning issues, at least around and off idle. It also seems on the large size for that compression ratio but I tend to be overly conservative. I suspect you would want a bored intake and throttle body to make use of the rpm it's capable of. As far as tuning while driving I think thats more ideal than most mail order but as you know it's a great deal of work.

**dave w** · 07-21-2023

Sample screen shots from WBO2 tuning spreadsheet.

906 iron Vortec heads with 2.02/1.60 valves and proper springs for cam from Clearwater Cylinder Heads
Comp XE256H-12 (12-256-4 grind) flat tappet cam
.449/.456 valve lift (I'm using the factory 1.5 rockers)
212/218 duration @ .050
112 LSA
Edelbrock 7116 Performer RPM Vortec intake
New complete throttle body from SPRPerformance (bored out to 46mm, 18lb regulator spring)
155 lph ACDelco Vortec fuel pump
3.73 geared rear end, 4L60E rebuilt trans with shift kit and heavy duty clutch packs
34" tires

Near Idle.jpg

Off Idle.jpg

PE Active.jpg

**dave w** · 07-23-2023

Possible ZZ2 timing tables attached:

**Fast355** · 07-23-2023

I would not worry too much about the TBI PCM being able to handle a large cam. I have tuned a 232/240 @ 0.050 on a 108 LSA with one in a 383 as well as a larger solid roller 246/252 @ 0.050 on a 106 LSA in a 406 with one.