More 73-91 Chevy to 6bt questions

[Niki]

OK, I finally have a crewcab in my posession, a 90 V30. It has a 454/400/205 in it now that runs great. How much of the factory engine harness, if any, do I need to keep? I'm figuring just for the guages? I plan on running a Dodge or a Delco alternator, so that'll all be wired up separate. The 454 is TBI, does anything go through the ECU for the guages, fuel pumps, etc? Thanks for any help, I have a complete Dodge donor and will probably do it in early spring.

 

[GOLIATHGMC]

I just began to disassemble my own donor for a similar conversion (see my sig). Might I suggest you have a look at another member website from the TDR - www.Devilscastle.net. His name is Timo, and his conversion is extremely well documented both on his website above, as well as on this forum. He made a dash cluster that is a combination GM/Dodge, and I intend to make one just like it (sorry Timo, it's just too good not to try to copy!). He used the tach and spedo from the Dodge, and the rest of the gauges are mechanical. Timo's thread is long, but incredibly thorough, and we should all hope to find a sliver of his talent somewhere in our own work. Good luck.

GOLIATHGMC

 

[Niki]

I just began to disassemble my own donor for a similar conversion (see my sig). Might I suggest you have a look at another member website from the TDR - www.Devilscastle.net. His name is Timo, and his conversion is extremely well documented both on his website above, as well as on this forum. He made a dash cluster that is a combination GM/Dodge, and I intend to make one just like it (sorry Timo, it's just too good not to try to copy!). He used the tach and spedo from the Dodge, and the rest of the gauges are mechanical. Timo's thread is long, but incredibly thorough, and we should all hope to find a sliver of his talent somewhere in our own work. Good luck.

GOLIATHGMC

I've looked at Timo's thread, that dash is nice for sure. Yours is more than likely carbureted, mine is TBI, don't know what the differences would be. I'm thinking of retaining electric pumps in the tank and putting a regulator on to feed the VE(my motor is a 92). But... the mechanical pump is pretty reliable. Who's mounts are you going to be using?

 

[DVolk]

You can keep your wireing harness , you just need to use your

ignition hot wire to feed the power to the pump . im shure you can

use your sensors from the 454for your guages , my self i prefer mechanical positive read guages with some slight mods you can use your stock speedo and fuel guage and add mechanical guages thats what i did



are you shure you just dont have a electric carbed engine , some times they look like a TBI if it is a TBI id pull the computer though and by pass it or get a 85 to 86 engine harness from a gas

 

[Niki]

You can keep your wireing harness , you just need to use your

ignition hot wire to feed the power to the pump . im shure you can

use your sensors from the 454for your guages , my self i prefer mechanical positive read guages with some slight mods you can use your stock speedo and fuel guage and add mechanical guages thats what i did



are you shure you just dont have a electric carbed engine , some times they look like a TBI if it is a TBI id pull the computer though and by pass it or get a 85 to 86 engine harness from a gas

It's definitely TBI, electronic spark control, etc. The early harness sounds like my best alternative, although I was going to try and use mechanical guages and have a pull cable to shut off.

 

[GOLIATHGMC]

Wiring issues....

Niki-

If you were planning on using mechanical gauges anyway, ditch the TBI engine harness and start over. Yes, my truck has a carb, but it has had 4 owners in its life and has been butchered many times over before me. It was originally a C/C from the factory, but it is hard to tell if it was once FI or not. At this point, it does not matter. I will be keeping the body harness, then blending in the P-pumped 12V wiring as necessary (perhaps the whole engine harness minus the Dodge gauges). As far as the fuel pump goes, you may look (for the sake of simplicity) to keep the mechanical pump, then drop the trucks fuel tank and change the pickup/sender assembly to a GM Diesel setup w/o the electric pump. Why complicate something that works good as it is?

The stock GM Spedo may or may not be a pain, depending on what you are using in the rest of the driveline. I am retaining the NP205 Tcase, so the stock spedo will still work- its driven off the output for the rear driveshaft. However, I will be using the Tach from the donor Dodge, so I will probably swap the Spedo over for asthetic reasons. We shall see.

As far as the Motor mounts go, I had some nice email conversations with a guy named Scott from TN, his TDR Login is SOswalt. He fabs some nice looking motor mounts that utilize the factory GM engine mounting locations, as well as a replacement crossmember for under the engine (replaces the large ugly setup that ties the frame together and locates the engine isolators). This crossmember is also REMOVABLE, which makes bottom end service of any kind possible and easier. He emailed me some pics of the parts earlier this year, and they are beefy. Since I have recently acquired my donor truck, I will be speaking with him again soon. Shoot him a PM - He was a pleasure to deal with.

GOLIATHGMC

 

[Niki]

Thanks for all of the suggestions. I'm going to go through the factory GM wiring diagram and see what all is in the engine harness, I'm sure there's stuff on there for the A/C and all of the guages, ignition, etc, but if there is any body stuff(lights, wipers, etc) I'll have to keep at least part of it. There's already going to be at least boost/pyro/tach added for guages, I'd like to run mechanical oil/water, but I may just make do w/ the stock guages for looks and space concerns. The GM diesel fuel pickups are a good idea, I wonder if they put plastic tanks in GM diesels like they did Dodges? I'll just snag the tanks. If I get a chance one of these days I'll take some pictures, its a pretty cool truck, will be much better w/ the Cummins.

 

[GOLIATHGMC]

As far as I know, there were no plastic tanks on our trucks (GM) during their production. However, there are Poly replacement tanks available for them, and I like the one I bought a few years back to replace an old rusty metal one on my CC. I would have to look into the records to see who it was made by, but I ordered it from good old JC Whitney. As far as I know, the only distinction between gas and diesel with the tanks is in the filler neck opening, and the pickup assembly (LMC shows separate listings for necks & pickups for diesel trucks). Since you will have to drop the tank(s) to wash them out of all gas anyway, you will have an opportunity to upgrade the parts and/or switch to poly tanks.

GOLIATHGMC

 

[NYCEGUY01]

One of your questions was one I asked and found no awnser to. The stock chevy ecm's are not needed for gauges etc. . The ecm moniters the sending units bit the gauges work independantly. My conversion is a newer truck but I found that gm did all thier trucks this way.



If you search for my older posts I listed the part #'s etc for a nice little voltage regulator that bolts onto the dodge alt and converts it to the one wire style that worked out great on my build.



Soswalt wont steer you wrong.



Avoid autoworld at all costs



Ok thats enough for now, if you hit any stumbling blocks just shoot me a pm and just dont give up, too many conversions never get finished out of frustration. If I dont know the awnser youre looking for I can probably steer you to someone who does.







#ad

 

[yellowk20]

I have oswalts parts high quality stuff and a decent price

 

[JTroiano]

I used all the factory gauges and took some wires out of the factory harness. To many!! had to put a few back.



I think my ECU switches the AC on and off. So I still have it. Haven't had the money yet to get the lines made for the AC.



It took 2-1/2 years.