i've been thinking about the possibility of fitting my 1984 z28 with tbi instead of the cc qjet.

i know many people are going to jump up and say not to do this, but it's an experiment i'd like to try.

what are some good donor vehicles to look for, and what all do i need to get from said donor vehicle?

i intend to stick this on top of a rebuilt 305 that i have, with a set of ported 416 heads with 1.94/1.5" valves. eventually, i'd like to fit a 5 speed into this combo.

suggestions?

thanks!

 

You might start by checking the parts for sale classifieds forum on the Board.

Donor cars are '88-'92 f-body LO3's (for the easiest fit). You could also probably use Caprice or truck TBI, but you're more likely to run into issues. The 350 LO5's will have the larger injectors.

You'll need the entire TBI intake & throttle body, obviously, plus lines, harness & sensors, fuel pump, ECM. The VSS changed from the back of the speedometer like on your '84 to the transmission on later models, so be aware of that.

Sure seems like a lot of hassle for very little gain. Makes a lot more sense to me to work with your CC q-jet.

 

I've been looking into the same. Not having any luck finding parts. TPI's everywhere. Can't find anybody that's willing to work on the carb and remanufactured are close to $400.

 

Work on it yourself. It isn't that difficult, certainly easier than converting to EFI. Even if it's FUBAR, it's still cheaper to get a reman than it would be to convert to EFI.

 

I've heard this before. My 89 has the VSS on the back of the speedo. Also what does the VSS have to do with the carb or the TBI? I have a cable from the trans to the speedometer head.

 

Converting to EFI will be expensive.

 

The ECM needs VSS input. Where it comes from may affect pin-outs (I have no direct knowledge one way or the other).

 

For the CCC setup the VSS is used for the TCC lockup. Not sure what else. On an EFI setup the VSS is used for the TCC, but also for items such as lean cruise, idle mode, IAC control, and some other stuff I can't recall at the moment.

Now, the optical VSS that sits in the cluster is 2K PPM (pulse per mile). It is directly compatible with the CCC ECMs and the f-body TBI ECMs. So no issue there.

The tranny mounted VSS is a 4K PPM A/C unit. The TBI and MAF TPI f-body's that have this type of VSS also received the 4-Out Buffer box. This box converts the VSS signal to 2K PPM which is directly compatible with the f-body EFI ECMs.

So the VSS is really a non-issue.

For my 2-cents on a CCC system. . . when it works it is OK. When it doesn't work, well, that is why you see so many people here on TGO (and else where) tossing the carb and distributor. And replacing them with a standard carb and a vac/mech distributor.

RBob.