I have a 350 in an old 305 car. 1986 tpi. It still has the 305 ESC module in it. What problems will that cause. I have read that I need to change the esc module to a 350 one,,,why? Am I getting un-necessary ignition retard? I "do" have a 350 knock sensor installed. Are they a matched set or what? I never get any pre-ignition, even with 87 octane. Am I losing a lot of performance/fuel mileage because of premature ignition retard? I used the search; but only found people saying that you "have" to change it when you install a 350,,,,,but no one says "why". My engine runs ok, but the gas mileage is poor. Also I have a 4.10 rear,,,,so it aint gonna be good anyway. If it is gonna help my mileage or improve performance a good bit, i'll change my ESC. Can anyone give me some advice? I guess my main question is: Am I gonna get $85 worth of performance increase by changing my ESC?? Thanks

I beleive the ESC module is matched to the knock sensor, and with the 305er its probably picking up false knock. I think I remember reading somewhere that it can pull as much as 20* out. Which in turn will kill performance as well as milage. I would save your $85 and go hit the local salvage yards. The modules labeled with BLH is for 305's and the ones labeled with HKR are for the 350's.

Thank you, is this ESC a "tpi only" item or will other cars have them as well, because the local tpi boneyard cars are already stripped clean.

I beleive there are other cars that you can find them in. I dont remember what they were off hand but I am sure some searching here on TGO will yeild some good results.

great balls o' fire!!!!
Just for the heck of it, i unplugged my knock sensor and holy-moly my car runs like a bat outta ,,,,, when I first unplugged it and cranked my car, I knew that something was up because it idled at 1500. And then when I put it in drive and took off,,,,it was super responsive and it RAN GREAT.

do you have a"gear"cam drive or anything else that
could be triggering the knock sensor?-if not,must just
be a bad(or wrong)knock sensor.I have heard flat tappet
and roller cam engines use different ESC modules