Had 85Z28 with 305tpi. Put a 350 in the frame. I tried to use the tpi sys. After several problems with wiring and so forth. I have decided to go with intake and carb setup. What type of things might help this go smoother, than my tpi experiance? Also have 700R4 in it curently. Is it posible to swap out with TH-350. What kind of difference will there be. Will I still have the lockup problems as with 700R4? Main reason for TH-350 swap is because the are a little more cheaper in price. I have used them in trucks in the past and found no problems. Hope you can help.

 

I dont have answers to much of that, but what I do know is that your gas mileage will be probably about half of what it was. You will lose overdrive, lockup, fuel injection and go to more cubic inches at the same time. Go to www.spohn.net I believe he has crossmembers to put the th350 in the spot of the 700. I dont know about lengths and whether you will need a different drive shaft or not but it would be something to check into. The carb route is deffinately cheaper, but you loose some of the benifits in the end(gas mileage, torque, easy starts). I dont know what you plan on using this car for or what your goals are, but these are some things to think about.

Ben

 

I switched to a TH350 from a 700R4 at the same time I replaced the 305TBI with a 383TBI. Your drive shaft will need to be lengthened by about 6 inches. I had a machine shop do it for $60 and I have given it hell and the drive shaft is SOLID. The very biggest mistake I made was keeping the computer/TBI. It just is not worth all the time and money you will spend trying to keep that ECM s h i t. In fact, when making major mods, the ECM is worse than s h i t, IMO. I went to non CC carbed induction and I have loved it. There is a leaning curve if you are new to carbs, but with carbs it is you, your tools and physics. When you have a comuter in there doing the thinking and counter adjusting your adjustments, it is pretty much out of your hands unless of course you want to spend countless hours and dollars trying to make it all work together satisfactorily by burning chips (what a crock).

:hail:IROC-Z
To hell with computer control.

 

You can always wire up a TC lockup switch or get a non LU converter. I have a non LU one.

 

This is all interesting still. I would like to have kept my TPI. Yes do to the fact of gas and it being a daily. But as I think back and look at what I have done I see the intake and carb. being my best choice. I mean with my 350 buildup I put in a mild cam. I will be putting new heads on sooner or later. No ECM seem to make sense to me. Do you guys think a TH-350 is a good way to go. I'll be driving my Z28 about 20 or 30 miles a day. None of my driving is really on the highway. Any thoughts also about what stall convert I should use?

 

When I had no OD in my 700R4 which was for several months, I was getting 14mpg, when I got the tranny rebuilt it jumped to 18mpg. Of course different motors will vary, but to me 20-30 miles a day isn't a lot, but you never know when the car might have to be driven greater distances, so why not keep the 700R4. A non LU converter is cheaper than a TH-350.

 

The TH350 is a BAD idea. I swapped to a TH350 when my 7004R died. Not only will your gas mileage suffer but first gear will suffer as well. With my 305 and 700R4 I could floor it in first gear and the tires would just spin. After the swap to a TH350, I could floor it and MIGHT get a chirp. It's just not as "quick" with the TH350. I finally switched back to a 700R4 last summer and I'll never go back again.

FWIW, I'm not sure what problems you had with the engine swap and the TPI but I swapped from a 305TPI to a 355TPI last October and had no problems what so ever. Everything should have matched up just fine with little or no modification.

 

Thanks for all the sugesstions. I think I'll just get my 700R4 rebuilt to handel specs. of the 350. The main problem I had with the Tpi was the wiring harness. Someone who owned it befor me spliced and diced it up. Then the computer went out on me. I replaced both wiring harness and ECM. Then fuel reg. also fuel relay panel. Still had problems with the injectors not purging sys right. Then shooting fuel in the right sequence. So then I decided to go with the carb and intake setup.

 

tpi does not fire injectors in sequence. They all fire at once.

Ben

 

Exactly. TPI is "batch fire" meaning they fire all at once like Momar said. There is no "order" for the injectors.