And so the Project Begins!

[cr92]

Dug my 87 out of the snowbank with the intention to get her back up and on the road!! has been parked for almost 5 years now.. i drove it one summer in 2010 and before that it sat since the mid 90's haha. looking for a few opinions on how to go about getting her road ready.
here are some details:

1987 chev swb with 4.3 tbi, th350, 2wd

Engine i have for it is a 1979 350 carb out of a k5 blazer

parts truck is my winter beater that is now unsafe for the road: 1989 chev 305tbi 4x4 swb with 5speed tranny

My plan is to turn the 350carb to TBI and stick it in my 87. i will be using as much off the '89 305tbi as possible. the rest i will have to order or get from scrap yard. i know this swap has been done lots so hopefully others can chime in and give advice on what i do and do not need. so far i think i need

350 computer
350 knock sensor
350 Electronic spark controller
350 throttle body ( or 350 injectors in my 305 throttle body)
fuel pump block off plate
carb to tbi adaptor for the manifold.

will the wire harness from my 4.3 connect to a 350 computer and will everything work or can i use my 305 harness or do i have to get one from a 350? anything else I'm missing? i plan on taking the pulleys and alternator brackets and stuff off the 305 and putting it all on the 350 to eliminate the v-belt system this is a direct bolt on true?

thanks for looking

[cr92]

tough crowd!! no one else done this conversion lately who might have some tips for a first timer??

[RandyP]

My only suggestion is to get a motor made for the TBI if you intend to use the TBI. Otherwise expect lots of issues. That's my .02 to you.

[cr92]

Im starting to think the same thing!

[SkinnyG]

I would not be afraid of what you are doing.

As long as the ECU receives signals from all the sensors, everything should run fine. It ~should~ be a straight forward upgrade, since the 4.3 and the 5.7 share so much in common. Whatever doesn't match up you can make to fit.

I would imagine (but cannot confirm) that the wiring harness should work just fine - but check that the ECU pinouts are the same between the 4.3 ECU and the 5.7L ECU. If pins are different, just un-pin them and move them to where they need to be for the different ECU. Electronic Schematics are like reading a road map, it's not that hard once you wrap your head around it.

I am planning to convert my carb/hei '77 to TBI this fall.

I totally encourage you to go for it.

[RandyP]

Do lots of research on vacuum created and be positive your cam is in the correct range for that reason. Also think about adding a vacuum canister. Get the gas tank made for the TBI in tank pump (baffles) or you'll have issues.

I stand by my advice. We put a new crate engine in my '87 and the engine was a carb designed motor. Never could get it to run right, would foul out plugs within 50 miles, lost more gas out the tail pipe than actually got burned, could not keep the timing correct, had hard start issues a lot of times etc etc etc.

Ended up yanking that crate motor out even though it had less than 1000 miles on it, sold it on CL for $400 and bought the correct crate motor and got it installed and have had a smile on my face ever since. I can only imagine the PITA it would be to start with a truck that was not TBI and try to make everything work.

[cr92]

My truck is TBI already. Its an 87 it came from the factory with a 4.3 tbi

[SkinnyG]

I have run "MegaSquirt", a DIY stand-alone EFI computer that is quite affordable and easy to work with. If you can tune a carb and re-curve a distributor, you can tune EFI. And, a MegaSquirt ECU is cheaper than a new carb. You have the advantage of having all the stuff you need to make it work, being EFI already.

RandyP is correct though - the factory ECU is tuned for a specific factory motor. Stray outside of "factory" and the computer goes "WTF?" and fuels accordingly (big cam = low vacuum = "we must be near full throttle all the time" = more fuel.)

Go standalone, and you can do whatever you want. Run whatever you want. Even swap back to the V6 (just tell the ECU you now have a 6, and re-tune accordingly).

TunerStudio software will "auto-tune" the engine for you, as you drive, assuming the Air/Fuel ratios you select are correct. Luckily, the default tables are generic SBC.

The last two MegaSquirt cars I have worked with were a Myers Manx with a hot rod motor running Mexican VW TBI, and a Lotus 7 replica with a Corolla engine running GSXR throttle bodies and Ford distributorless ignition and Honda injectors. They run great and are super reliable.

I'm not affiliated, this is just an option that you have, and it works very well.

[cr92]

I must read into that a bit more... Sounds great

[blazerkid]

all you really need is the 350 computer everything is all ready their tbi 305 intake on the 350 and put the 350 in the truck

[cr92]

gonna leave the 350 4barrel intake on it and just use an adaptor plate! i just need a set of 350 injectors and computer and spark controller!

[silverbear]

One thing to check before you start with the v-belt to serpentine conversion is, on the heads from older generation SBC's, the drivers side will have three mounting holes but the passenger side will only have one. The passenger side needs three holes to mount the newer brackets from your donor truck.

Don't let that stop you from making the conversion. It is still possible to switch to a serpentine belt but you may have to use custom brackets. There are several companies out there who make brackets for this conversion and they are all very proud of them.


Second penny of advise. It is nice that parts are so interchangeable with just a little bit of research and effort but back then GM used the same connectors for all kinds of stuff so... LABEL EVERYTHING! This will save you a lot of headache is the future. It also helps to take lots of pictures before you disassemble.

Best of luck.

[Ziegelsteinfaust]

Also fuel injection cams are slightly different then carb cams. If your thinking a cam change get a fuel injected version.

[cr92]

thanks so much for the advice guys! everything helps. I spent the day checking local scrap yards for parts and couldn't find anything with a 350 in it! they have pretty much everything crushed now which sucks!

Going to call around on monday to a few spots out of town and see what i can come up with if not I'm gonna try ebay.

I was on rock auto earlier checking out 350 injectors.. can anyone confirm a part # for the injectors and are they both the same? gonna post another topic on the board in hope of a faster response... wants to get the 350 all squared away and ready to drop in very soon!