87 k5 Carb motor swap

[Tyler Hart]

I've been reading around on the site but only seem to be able to find how to convert a tho motor to a carbeurator. I was wondering how involved it is to just swap a carb motor in to a tbi truck. I have a complete running and driving donor vehicle. The tbi in my 87 K5 quit on me and i have a 82 K20 with a motor thats been gone over recently and a mild cam that I don't drive anymore. So would like to put that motor in my blazer.

Thanks for any info I can get.

 

[Bent77]

Well first off, if you really want that other motor in your k5, thats cool. Being able to sell the TBI engine complete with harness would probably get more $$than separated and not running. So fixing it might be a good option even if you move on


You need to pull the tank and remove the tbi pump, and set the tank up for a carb. Mechanical fuel pump

The TBI harness complete is a desirable item, so carefully removing it is worth your time. You will have to wire back for the distributor, probably a temp sender.



Then the linkage is possibly different. Also is it an auto or stick? Do you need a TV cable for the kick down


I will never use a carb again...


Be reasonable and consider using an aftermarket fuel injection kit. Figure your costs and options before you start. You may dump a ton of money in this that could have been used for an upgrade.

Either way

 

[dyeager535]

If the *TBI* quit, why would you swap a motor?

I know it's not what you want to hear, but you aren't going to get many people to recommend an injection to carb swap anymore. Injection is better than carburetion in every regard (broad statement, not completely true lol). Many of the components on my injection setup are original 1987-1989 parts. My carbs caused me more problems than the injection ever has.

Realistically it's just a matter of tying a bunch of wires up, modifying a couple (the distributor IIRC) and as mentioned, all the various components that are different on the '87 due to TBi than the '82. But since the body is the same, everything will swap over. You'll also have to consider the transmission, depending on if you plan to go with what is already in the truck or not. The K5 and K20 I'm assuming have different trans.

Whatever you do, don't cut the wiring. One of these days you'll realize that being able to hop into the vehicle, turn the key, and drive away, regardless of weather, is better than the alternative, and is far more pleasurable to drive.

 

[RootBreaker]

You need to pull the tank and remove the tbi pump, and set the tank up for a carb. Mechanical fuel pump

I'm running an electric fuel pump with my carb. My motor (1991 caprice roller L05) does not have a lobe on the cam for a mechanical fuel pump. also isn't tbi a low pressure system? if not you can put a regulator on...

now I agree with you... I have carb and want it gone. Even this newer truck avenger aint bad but I'm doing different head spinning thoughts.. 5.3L or 6L or 8.1L... that is my delema.. hah

 

[Tyler Hart]

I was going to swap the entire drivetrain from the 82 because it's a 465. That way ill get rid of the 700r4 which I'm on my 3rd. But if the consensus is that going back to a carb would be a bad idea, then how about converting the 82 motor to TBI. Between the two trucks do I have most of the pieces? I'm sure it's not as easy as swapping distributor and intake.

 

[dyeager535]

Unfortunately no, it's not.

You can try TBI on the motor, but it's unlikely the stock tune will be very good on a warmed over motor. The TBI intake won't bolt to it unless it's got later heads. You could use a carb to TBI adapter, but if the TBI doesn't work satisfactorily after you do the swap, and decide to go carbed, you wasted the money on the adapter.

I think the 465 is ALWAYS a good swap lol, don't blame you for wanting that. Really want a PROM from a manual truck (or reprogram) when going auto to manual or vice versa, as the tunes are different, and it eliminates the park/neutral switch problem. IIRC even the 465 swap isn't going to be super straightforward, the pre-85' has a frame mounted bracket that the z-bar rides on, and it sure looked to me like a real pain to get that bracket in place with the body in the way. Hydraulic clutch is the way you want to go, your firewall is set up for it, but the problem is finding the bellhousing and the pedals for cheap.

 

[Tyler Hart]

I figured it was going to be a pain. I do have another TBI motor laying around that runs. What do people do to get a little more power out of them? I always thought the throttle bodies were kinda doggish. Maybe before I drop that motor in I could give it a once over and pull some more out of it. Always wanted it to have a 383 is that possible out of a TBI?

 

[Bent77]

Yes, but honestly it’s a lot of work for a little gain

Really, selling the two motors you’re not going to use and selling other parts you don’t want to finance something like a Holley Sniper or FiTech is better. I have a really good engine limited by the TBI injection bolted to it. Probably left 50 horse on the table.

I could get it back with hours of data logging and retuning it, with some other investment to get it done. More likely I will just go aftermarket FI