Electronic Spark Control Module (ESC) part #16128261, do I NEED this for my 350 to control the timing? I don't see how it can be different, sence knock, retards knock. I have the 350 knock sensor in the block but I'm still using the stock 305 ESC.
Can somebody somehow prove that this is not a good thing.

The knock "signature" is different between the two engines. Knock is primarily a function of bore size. Since the 350 bore is larger than the 305, the "sound" that knock makes will be different. Do your engine a favor and get the proper knock module, or upgrade to '730 and a 350 memcal tuned to your application (and the speed density knock sensor).

I have TBI, no TPI.
I thought the knock sensor was responsible for picking up a the noise and just translating the knock into a signal.
I'm all speed density so are the ESCs really different for TBI? I mean I thought the only difference between the 350 (Lo5) and 305 (Lo3) TBI applications was the knock sensor. I'm going to go to the parts store today and dig up some information on what the part numbers are for the 7747, 8746 ecms and 350, 305 applications in trucks/vans.

from what i've read and understand, the knock module should be changed since it has a filter that is characteristic of the engine in use, however, this doesn't hold too much weight since I have a 350 van module, and a 305 firebrid module, and they both have the same label on them. Some one may have replaced one of them incorrectly though, and if the bore size is predominently the factor in the module selection, that may be why so many guys running 383 engines can get away with using a 350 module. The knock sensor itself i wouldn't think would change, it simply is a microphone that picks up the vibrations. There are a couple different versions, but i guess the major decision factor would be to compare the part numbers. Let us all know what you find out when you visit the auto store, as I'm sure there are others who have the same questions.

The KS is different between different ECM families; whether the signal output is different or merely attenuated is unknown to me - others have reported success upgrading a '165 ECM to '730 ECM and using the original KS with a resistor in series.

I'd verify the EST module p/n with a dealer computer, just for safety's sake.

Okay, didn't get to the store today, too much school work.
Now my next big question. I have a flat tappet cam in the engine right now but the knock sensor is for a roller cam engine. I understand that the roller cam engines do produce some noise and from what I've gathered through searching, it's filtered out by the knock sensor. So do I need to get a knock sensor for a flat tappet engine or is it only if I went from a flat to roller?

btt
i need to know too!!!

btt

as i understand it, all that needs to be swapped is the KS itself. i recently swapped my 305 for a 350, had a bit of a ping, and swapping the KS to the proper (350) sensor fixed it. i didnt touch the esc.

the knock sensor is a piezo device that translates pressure (~vibration) on a crystal into a voltage. in a sense, like stated before, it is a sophisticated (though simple) microphone. all the esc does is translate the signal and modify the timing.

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'89 TA - 5.7 TPI (L05, was originally a 305TPI), T5-WC, 3.08 Posi (Drum)

i have a 91z28 that i just replaced the 305 with a 350 and was wondering if i do need to change the ESC module? I put in a 350 knock sensor. i just feel like the engine has a problem somehwere it this catogory. where can i get a new module

Module from GM (AC/Delco) is part# 16128261 for 350,available at any GM parts dept.
Changed both Sensor and Module on mine,as I was told it's necissary when swapping 350 in place of 305. Mine's TBI also.
Recommendation came from Chevy High Performance Magazine.They put me in touch with Ken Casey at Burt Chevrolet in Englewood ,CO.(303)789-6878 Parts Dept.
He sent me 350 Tuck injectors, knock sensor and module as a package-deal.
CHP magazine says he's the guru for 305-350 TBI swaps.
He was very helpful, and I'm sure he'd be happy to answer any questions you have, if you call him.
-Rich-

with a resistor in series??? thats strange.. does anybody know y theyre doing that?? i know electronics a little but im certainly no expert..

The only thing I can think of . The 165 and tbi uses a 100k ohm ks. The 730 uses a 3.9k . The ecm does a self check forced knock to test circuit. Just better to get right knock sensor for the application .