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looking for the best heads,intake,cam for a 1986 305 TPI
Hello all ive been searching all over the web for good parts to throw on my 305 tpi for my 86 trans am all im really looking for is a strong cam, heads and intake and ive been coming up short so i thought itd be best to ask you guys who actually know about these motors. im not looking to make 500 horses yet but i want a good set up around 400 if anyone has a good reliable build set up that they have done it would be greatly appreciated.
Re: looking for the best heads,intake,cam for a 1986 305 TPI
Before you replace anything else in the car, upgrade the exhaust system and O2 sensor. that is the main power constrictor on these cars (the single wire O2 sensors require LOTS of back-pressure to work correctly. If you don't care about horsepower and just want the lopey muscle-car engine sound, they just buy whatever you think sounds coolest. with not TOO much duration on the cam-lobes (back-pressure required to function correctly) if you do not perform an exhaust system upgrade first, including upgrading to a 3 wire O2 sensor, then your car will run like **** in anything but a stock configuration, no matter how hard you tune. expect and 30+ HP boost with a new exhaust system, new high flow cat and mufflers, or straight-pipe. the TPI engine does not have a downstream O2 sensor and does not care
(Edit: any and ALL modification to the engines of these cars usually requires a re-tuning)
(Re-Edit: I have an ADS superchip from back in the day in my car and it works fine with my high flow cat, the stock one... not so much [tho that could be because that chip came out of a corvette TPI {I am operating under the assumption that all TPI PROMS are compatible with same ECM same displacement same transmission donor cars} Tho that car may have been a manual])
Last edited by Nekomancer; Feb 22, 2022 at 07:34 PM.
Reason: Adding information I forgot to
Re: looking for the best heads,intake,cam for a 1986 305 TPI
Originally Posted by Nekomancer
Before you replace anything else in the car, upgrade the exhaust system and O2 sensor. that is the main power constrictor on these cars (the single wire O2 sensors require LOTS of back-pressure to work correctly. If you don't care about horsepower and just want the lopey muscle-car engine sound, they just buy whatever you think sounds coolest. with not TOO much duration on the cam-lobes (back-pressure required to function correctly) if you do not perform an exhaust system upgrade first, including upgrading to a 3 wire O2 sensor, then your car will run like **** in anything but a stock configuration, no matter how hard you tune. expect and 30+ HP boost with a new exhaust system, new high flow cat and mufflers, or straight-pipe. the TPI engine does not have a downstream O2 sensor and does not care
(Edit: any and ALL modification to the engines of these cars usually requires a re-tuning)
(Re-Edit: I have an ADS superchip from back in the day in my car and it works fine with my high flow cat, the stock one... not so much [tho that could be because that chip came out of a corvette TPI {I am operating under the assumption that all TPI PROMS are compatible with same ECM same displacement same transmission donor cars} Tho that car may have been a manual])
how do you switch from a single wire o2 sensor to a 3 wire. I have an 85 T/A that was swapped to a 5.7 tpi. It has headers and larger exhaust pipes, no cats. The exhaust does follow the same placement as stock would except its dual instead of a y pipe and ends right before the rear diff. Do I need the o2 sensor. I can't imagine there's enough back pressure for the o2 sensor if what you're saying is true. I haven't driven the car yet. I bought It as a project and it's very close to being done. So I even need the o2 sensor. I'm still learning and would appreciate any feedback thank you
