Newbie here. Love the forums so far. However, I need some help. I removed the 454 from a 1989 k3500 and installed a 350 from a 1989 V1500 suburban. Before you ask why in the world would I give up a big block for a small block, I'm not. The truck is my friend's and the suburban is mine and getting the 454. Straight trade and paying me labor for the install. Nice huh? Couldn't pass it up.
I've read all over that the only difference in the IAC is that 2 wires are swapped. I did find the attached drawing thanks to EagleMark back in 2012 as well as the following comment:
1227747 IAC wiring to IAC for Big Block and Small Block
Here's one that drives people nuts. SB and BB IAC are wired differently.
Wiring:
SBC Connector
IAC Plug
A ~11.86 v Lt Blue/White Stripe A Hi
B ~.452 v Lt Blue/Black Stripe A Low
C ~11.86 v Green/White Stripe B Hi
D ~.453 v Green/Black Stripe B Low
BBC Connector
IAC Plug
A ~452 v Green/Black Stripe B Low
B ~11.84 v Green/White Stripe B Hi
C ~.452 v Lt Blue/Black Stripe A Low
D ~11.84 v Lt Blue/White Stripe A Hi
My readings with key on are as follows:
Lt Blue/White Stripe- .4
Lt Blue/Black Stripe- 11.2
Green?White Stripe- .4
Green/Black Stripe- 11.2
So my question is which position on the IAC do I connect the wires(square SBC plug)?
Then when I reverse the procedure and put the 454 in mine where do I put them? I might very well be making this harder than it needs to be but electrical is my weakest area.
Also, the 350 has the ESC and knock sensor but the 454 doesn't have either. What am I going to have to do on the 350 since it has the 454 harness?
I should mention that even though they both have the 1227747 ECM I swapped them.
Thank you in advance!
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