TBI advice needed (donor vehicle, kit, or DIY harness)

[71_K5]

Hey All,

My '71 was stolen 10 years ago and I then got into Early Bronco's. Well, I'm back!

I picked up a sweet '72 350/T350/NP205. I converted one of my Broncos to EFI and installed an overdrive tranny and loved the performance/economy of the combo. I want to do the same for my K5.

I picked up a 1988 K5 Blazer (running) for $800 for a donor. After adding up prices to refurbish possibly worn components such at injectors, HEI dizzy, etc; I'm now considering just calling up Howell and ordering a complete kit.

The other option would be to order a new Painless harness (to eliminate some possible wiring gremlings) and still use my 88 K5 as a donor for the hard parts.

HELP!!! Seriously, for those of you who have done it, what would you do? Benefits/Cons?

Other plans are to install a late model 700r4 and NP241. (Anyone know if there is a SYE kit available with mechanical speedo port for a passenger drop NP241C - I want to keep the factory dash and run an inline VSS for the TBI)

THANKS MUCH,

Jim

 

[dyeager535]

Hey Jim,

If the '88 runs good, use it as-is. When things start going wrong, replace the wear items...O2, injectors, plugs, wires, etc. If it runs bad now, then yes, you might consider just buying everything new. The '87 I just bought (for the body) runs and drives like a champ, I'd be a FOOL to think I can somehow do better by dropping money on possibly worn components.

I can't really help you on the '72 speedo issue, but I feel your pain. I'd want to keep the stock speedometer as well. The '90-91 electronic setup is much better, but again, I see why you want to do what you want to do.

 

[70jimmy]

Recently we put a 93 350 tbi motor in my jimmy. I used the stock tbi unit on the motor and ordered new computer #7747, chip, prom, and wiring harness from howell. Works great.

I stayed with the 205 and kept the stock speedo hookup. I figured by keeping the stock tbi I could get replacement injectors anywhere. the guys at howell were very easy to deal with and the harness was plug and play. We did have to put an O2 sensor in my exhaust but only because I modified the original rams horn exhaust manifolds so I wouldn't have to change my exhaust right now.

Worked like a champ at Blazer Bash this year. FYI I am running 4.10 gears with 37's and I twin sticked the 205.

If you need more info... Part #'s and costs just let me know.

Since the new motor was serpentine setup I did have to get a new fan because it turns counter-clockwise unlike the old one.

 

[bigblock72]

If the wiring harness is in good shape reuse it. They are an almost stand alone harness in that truck and are really easy to modify. I'd be more than happy to clean up and modify it if you want to ship it to me. There is only a few wires that have to be connected to the truck: coil power and pcm power-switched, pcm power-battery, fuel pump and that's about it.

An 88 should already have a 700r and 241 setup. JB Conversions makes a SYE kit w/speedo.

There are quite a few different inline speed sensors and are relatively cheap.

I have pretty much this same combination in my Blazer and have been very happy with it.

 

[FightinTXag]

I took everything from an '87 Burb and swapped it into my '85. It was running fine. The only thing I replaced was the O2 sensor, and that was only because I broke it dropping the engine in.

Spliced the fuel level sender wire, taillights, one wire for the underdash courtesy light, and one of the green wires that lead to the a/c compressor or old idle kickup solenoid. Of course, '88 to '71 will probably take a little more reworking.

 

[71_K5]

Thanks for all the great feedback! I'll just use the '88 as a donor. Unfortunately, it was a mid year and has the 208 tcase. I do have an NP241 with the 700r4 adapter behind it, but it is slip yoke and vss only.

 

[bigblock72]

I do have an NP241 with the 700r4 adapter behind it, but it is slip yoke and vss only.

I'm pretty sure you can get a speedo cable SYE from JB and fix both problems.

 

[Mike D]

I converted my 81 Chevy K20 to TBI. I must admit I tried to go cheap, getting a wiring harness from an 88 astro van. What a pain in the butt it was to trace all the wiring and remove the unnecessary duplicate wiring, like to alternator and polution sensors. It never did run good. I finally bit the bullit and purchased a wiring harness from Howell. What a differance, straight forward wiring adequate wire length to the sensors, new pliable ( not brittle ) conectors. Bottom line - very happy. When I step on the gas " the boys " feel like they are being yanked off me! If I ever convert another vehicle to TBI I will save a lot of frustration and time and buy a complete kit from Howell.

1981 Chev K 20 350 w/ Turbo 400 2300stall converter 205 T case 33" tires posi