I may have the opportunity to buy a 68K mile 350 TBI out of a wrecked 1/2 ton pickup to replace the dying 350 in my '77 z-28. I'm new to TBI, and have a few questions:

1) What's this engine worth? 68K miles, driven by a little old lady to church on Sunday, literaly.

2) I know I could buy a $350 intake and just convert it over to a carb, but I would like ot keep the TBI. I would need to somehow wire the thing up. What's the most cost-effective way to do this? Painless Performance could sell me a wiring harness, but is there a cheaper way?

3) With a new cam (like the LT1) can I get 340 hp?

4) Besides wiring it up, and installing an electric fuel pump, what else is required?

Thanks for all the help.

 

The shortblock itself is good. The heads and cam really suck. With good heads and a mild cam, 300-320 HP are feasable with tbi. Youll have to tune it, of course. This requires around $100 of extra hardware and any old laptop so you can datalog and make changes. Sounds difficult but once you get used to tuning with efi it really then comes down to engine theory and how to apply it to get the motor to run good. The engine theory bit is usually the hard part.

As far as teh harness goes, you can get a harness and ecm out of a tbi car if you need one. It should swap right into your car. IIRC, the truck harnesses are longer.

 

Check here to figure out which engine it is...
http://users.apex2000.net/whardie/horse.html

"Vin K" would be the better engine of course - just so you have a starting estimate on where you are.

I'd just use the Truck harness if avaliable. The extra length could make install and wire routing easier, as well as it being a much simplier swap - keeping everything in factor "Sorts" so to say.

A simple cam swap won't yeild anything near 340 HP. Maybe some AFR head, cam swap, single plane, new TB, and lots of tuning (assuming you already have a complete exhuast)... but none the less, you'd get a reliable work hose that could make respectable power for pennies on the dallor.

I'd offer $500 for the engine/trans and harness/ECM.

 

Regarding wiring and the computer, how many wires actually run from the computer back out to the car? I can make the water temp, oil pressure, electric fuel pump, and starter work, it's just the computer that has me concerned.

 

You really need to have a speed sensor to make it all work correctly. Painless has a way around it but I think it only works with their chip. You can slap any old carb intake on it if you slot the inner 2 intake bolt holes, if you don't want to do that you can get an intake setup for the different angle for much less than 300 bucks.

 

Trucks only have a few sensors (well, same with fbod's for the msot part, minus 1).

MAP, O2, Knock Sensor, TPS, Temp, and IAC. You will have some other misc leads, such as for the EGR selonoid, AC Clutch, etc, but its VERY STRAIGHT FORWARD! Very few (if any) relays. Also, the truck's use a large power distribution block which makes things simple for finding common grounds, or 12 volts.

This is not a hard install - I wouldn't be too concerned about the ECM.

 

Getting all the wires from the computer to the engine wouldn't be hard. It's the wires from the computer to the rest of the car that concern me. How many are there? A ground, main power, and ignition on/off, but what else? I assume water temp and oil pressure never go through the computer.

 

I think - Oil pressure, coolant temp, vehicle speed, and you would have to wire up a CSC light.

 

I put an 88 van harness & ECM 1227747 in my 71 chevy pickup. No sweat. Save EVERYTHING from the truck and tag all the plugs when you remove it. Leave the harness for under the hood pretty much alone, and split open the one on the inside of the firewall. Basically, just run the fuse block from the truck and hook up the wires from the truck gauges to the gauges in your car. Hook the ignition wires from your car to the ones in the truck harness. Starting to catch on? You're basically running the truck harness with the controls in your car. For exterior lights, you can leave that stuff alone in your car and just power the system from the truck harness. BMonteSS is right, you need the VSS. I custom fit the speedo head containing the VSS from the van into my 71 (can't tell the difference). Wire up a check engine light, and you're set.

Nice thing about going Chevy to chevy is that most of the wires are the same color! (fuel gauge, ignition, starter, etc...)

Good luck & Happy Tuning.
Mike