TH350 & 700R4 factory wiring and vacuum mods

[T-ROD]

I started this thread in case it might be another idea someone besides me could use, noticed alot of people are spot on as I know myself some of the little differences that have to be converted and/or added or deleted when doing a swap. Put alot of work into my ride as I wanted it simple but effective and make use of available sources as well, My truck came originally with a 305 ESC and a 700R4, it now has a nicely built 350 with TH350 mated to the original NP208 case, I wanted an original look so I kept many wires and kept emmisions from can but deleted EGR valve and air pump, but it still resembles a nice factory engine compartment for the most part, I made use of the TH350 by slightly cutting a short shaft 2WD unit, it lined up well, another mod that was I thought fairly cool was that I didn't want my electric fan to run full speed unless it was running similar to some completely ecu controlled cars, so I made use of my 700R4 controls without cutting wires used plug and a pressure switch from TH350 and when engine vacuum is present and it's in gear I have a fan turning in traffic or it is overridden by a temp switch also, the egr bleed solenoid controls breather vacuum when cold thru temp switch even though it's not completely factory it looks nice being there and it is effective and works well, also I used the solenoid because it seemed good because it's literally right beside the breather vacuum motor and it can bypass the mechanical switch when cold to draw hot air, and less chance of vacuum leak due to it being off and no vacuum present when warm. I know these mods seem far fetched and I feel funny explaining them but I'm just a big dreamer and it turned out very good, I also still use cruise control and my ESC system which is the slightly small computer used to control spark knock, and all my factory AC and charging plus electrical looks and is still factory except part of it which still runs through factory connections, I even went as far as getting the factory plugs to connect factory temp switches and sensors added to factory harness, and as well as inside my cab (little off subject) all original except pioneer CD player which is black & chrome as my dash and lights red as my truck is red, plus some fog lights in bumper(exterior) but I have no added switches or many added relays or wiring, just few simple upgrades that seem very optional to the truck, just thought it were good ideas, please don't bash me, but they seem nice, considering there's a whole lot of 700 to TH 350 swaps

 

[T-ROD]

Btw, I do realize some of this wasn't tranny related but the egr valve was originally controlled by trans switch in fourth, and most of these were leftover connections that I didn't want gone and though of useful things to do with them, and I left out that I have plastic line going to new tranny for vac modulator from manifold pressure port and it's bent as neccesary for factory look as well, and all plugs all still intact and present but repurposed some and it worked well and runs good

 

[HotRodPC]

So what your truck had OEM was the LE9 305. Supposed to be a 9.5:1 compression engine with the ESC. That was to be GM's engine to meet the Fed Gubment mpg requirements of the 80's. Many think the purpose of the ESC was to control detonation or pinging so it really wasn't needed or worthy of having hooked up and quickly bypassed it by cutting the wires at the distributor and twisting a couple together killing the abiltiy for the electronic ignition module to control timing. The ESC did in fact control detonation but it's purpose was to be able to run with the timing advanced as far as possible without pinging to improve mpg. With ESC working properly you could probably get better performance and mpg with say Unleaded Plus 89 or 91 Octane rather than 87 because the timing could be advanced further without pinging. Many aren't aware that the ESC Ignition module has the ability to advance or retard timing in real time as you're driving. It may advance timing for performance and then you start climbing a hill it might then retard timiing if the strain on the engine to climb that hill was causing detonation. ESC in it's time wasn't bad at all considering no cam or crank sensor. Now days though, there is so much better technology though more complicated. So if you have the ESC hooked up and working properly you should be getting better mpg than others who aren't using it.