I just found out today that the knock sensor for 305TPI is different than the one for the 350TPI.... two different part numbers. What is the main diff between the two?? I just took out my 305 TPI engine and I just put in a 355 TPI engine. I bought a new knock sensor for it but I bought the one for the 305 TPI because I didn't know the two were different. I haven't started the engine yet so I don't know if it'll work or not. For now I'm still going to be using the stock 305 chip. Will this knock sensor work ok since I'm still using the 305 chip??? If so, if I change the chip in the future will I have to change the knock sensor as well?? Please let me know something ASAP because the engine will be ready to run within the next two days.

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1986 Trans AM
305 TPI
Well over 200,000+ miles (speedo/odometer non-funtional! Odometer reads 142,000)
4 Wheel Discs
9 bolt Borg Warner Rear (2.77's....oh joy) :P
Completely Stock
Current Project: upgrade to a 355 TPI, 6" rods, 9.7:1 Compression, Stock TPI ported, 24#/hr LTI injectors (cleaned and flowmatched by Cruizin Performance), Hedman Shorty Headers, 3" exhaust with 80 series flowmaster, SBC 993 heads completely redone and modified for 1.6 RR, Comp Cams XE262-14 TPI Cam, Holley AFPR, TPIS airfoil, MSD wires, MSD 6-AL Ignition, Hypertech hot coil.

 

[QUOTE]Originally posted by 86TpiTransAm:
[B]I just found out today that the knock sensor for 305TPI is different than the one for the 350TPI.... two different part numbers. What is the main diff between the two?? I just took out my 305 TPI engine and I just put in a 355 TPI engine. I bought a new knock sensor for it but I bought the one for the 305 TPI because I didn't know the two were different. I haven't started the engine yet so I don't know if it'll work or not. For now I'm still going to be using the stock 305 chip. Will this knock sensor work ok since I'm still using the 305 chip??? If so, if I change the chip in the future will I have to change the knock sensor as well?? Please let me know something ASAP because the engine will be ready to run within the next two days.

yes it will work fine. i put a 5.7l roller motor in my '86 t/a and it runs fine. been using the OTC monitor 4000e to scan my car.

 

So you're saying you're still using the 305 knock sensor on your 5.7 roller motor? Is that an aftermarket chip as well?

 

You should change the knock sensor. They are different. 305's and 350's resonate at different frequencies. What's the big deal, they dont cost much....better to have a new one on your new engine anyway. Cheap knock insurance.

Your prom should also be changed. You will run, but not to your potential with a 305 chip.

If you have not adjusted your fuel pressure, you also need injectors or an AFPR. If you run your 350 at WOT with the 305 prom and injectors, without raising the fuel pressure accordingly, you will run lean and risk messing up your new motor.

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Mike Metzler (Desert86Roc)[*] Check Out:SpeedWorldMotorplex.com[*] Check Out:Chevrolet F-Body Online Part & Illustration Manual[*] www.MetzlerRacing.com

Best ET @ 1250 ft[*] 15.352 @ 91.215 mph (uncorrected)

 

#1. The knock sensor IS new. Hence the reason for this post. I bought the wrong knock sensor and now that I have it installed in the block, the parts store will not exchange it.

#2. The chip is just a temp. situation

#3. If you would have read my mods on my current project at the end of my original post you will see that I have 24# LT1 injectors and an AFPR already.

Thanks for the post though.