87 tbi to carb swap?

[ELMER MUD]

i got an 87 and wanting to do some perf. up grades to the moter so im going to can the tbi and goto carb i already have dist and intake what im woundering is what do i haft change in the wiring to make this happen thanks for any help

[76stepsidechevy]

Ever thought about the holley 670 throttle body ? You can pretty much eliminate all the wiring and computer for a carb. The only things that will need power will be the distributor and electric choke if you want.

[rfmaster]

Originally Posted by ELMER MUD

i got an 87 and wanting to do some perf. up grades to the moter so im going to can the tbi and goto carb i already have dist and intake what im woundering is what do i haft change in the wiring to make this happen thanks for any help

Going to carb is the biggest mistake you'll make with LO5 (350) engine. Instead of gaining performance you'll loose it. To improve performance with TBI you can do the following:
1) replace stock cam with CS1014r, MT2, Edelbrock 3702, Lunati 60101LK + many other TBI (ECM) compatible cams.
2) true dual exhaust 2-1/4 or 2-1/2 (headers are preferred, CI manifolds are good as start) - 3 or 4 wire O2 is required with headers.
3) replace stock fuel pump and increase fuel pressure from stock 9-13 PSI to 16PSI (requires stiffer fuel pressure regulator spring).
4) Upgrade EPROM to match your engine upgrades.

With above changes (without head work) expect HP to go from 180 to 230HP. Stock intake is NOT real limiting factor at these power level, but Edelbrock 3704 should provide another 10 to 15 HP over stock. Moving away from stock heads to World castings or vortec style heads (non OE) will pick-up another 40 to 50 HP. Vortec heads is another route, but require different intake and EGR plumbing. Tuning will be required - (EPROM upgrades, changes). At 280HP level you are going to approach fuel delivery limit of 62 lb-hr injectors (@16PSI). Stock 1-11/16 bore TB flows 470CFM and is more than adequate for street engines operating under 280HP.

//RF

[355bullet]

have you looked into the Atomic EFI from msd? Its self learning, easy to install etc..
check out this one
http://www.atomicefi.com/forum.aspx?g=posts&t=16692

[76stepsidechevy]

[QUOTE=355bullet;5331100]have you looked into the Atomic EFI from msd? Its self learning, easy to install etc..
check out this one
http://www.atomicefi.com/forum.aspx?g=posts&t=16692[/QUO
TE]

Are you running one? I have an old holley projection setup im running now and was looking into that setup.
Posted via Mobile Device

[355bullet]

Yup, runs great! Throttle response is amazing. Self Learning System works great.
I'm running the return on mine. I have dual tanks, uses one fuel pump.
Only 8 wire hook up, you can adjust your timing with the hand held. No Laptop needed. Uses also the factory throttle cable.
http://www.atomicefi.com/





carb i was running


Stock air cleaner fits!


truck on lift

[AusTx68]

I will take a shot at actually answering the original question. I made this swap on my 87 454 and I have been VERY happy with the results. The BBC TBI setup is a little different so my swap required less parts. I didn't need an intake because the 454 TBI uses a spreadbore intake with a TBI adapter.

Aside from a carb, intake, and distibutor you will need a fuel pressure regulator. That's if you plan to use the stock fuel pump. I picked up an inexpensive Holley regulator which dropped the pressure to 6 lbs which was perfect for the Edelbrock 750 carb I was using.

To connect the stock fuel lines to the regulator/carb, I used a tube cutter to cut the pressure line about 15 inches back from the throttle body. I slipped over a 3/8" fuel hose and secured it with hose clamps. I also cut the fitting off the return line and capped it since it's not needed. Of course all the smog stuff was removed and the EGR was blocked.

There is a connector that plugs into the TBI distributor that has what looks like a 12g red wire. I tapped into that wire to power the HEI. I tapped into one of the hot wires that fed the fuel injectors to power my electric choke. The harness is still in place with all the non-throttle body connectors still connect. None of those sensors are being used. At some point I will go back and clean all this up. For now it works.

One other thing. In my case I needed to lengthen the accelerator cable to reach the carb linkage. It was about an inch too short. I made it work using a cotter pin. Not pretty but it works.

[355bullet]

AutoZone now carries throttle cables. I scored one last week.
They seem to work better than the OEM ones, it was 15bucks

[AusTx68]

Dang, that is one clean bay. You could eat off those floors!

[ELMER MUD]

thanks austx68 thats just what im wanting to do to mine. im wanting to build a street strip truck and i know you can make huge hp # with injection but i will just stik with the old skool stuff. thanks for all the info

[425HP409]

ELMER MUD, if you have a 454 and are taking the fuel injection off, I would be interested in the complete fuel injection system.

[AusTx68]

Originally Posted by 425HP409

ELMER MUD, if you have a 454 and are taking the fuel injection off, I would be interested in the complete fuel injection system.

If not hit me up. I still have all the tbi stuff I pulled off my 454. Its all for sale.
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[walkerscott]

Does this system control the timing ?

[rfmaster]

Originally Posted by walkerscott

Does this system control the timing ?

Yes,

[ELMER MUD]

its a 350