TBI to TPI conversion
 

Whats up guys. Thinking of converting from my stock tbi setup to a stock tpi setup. A friend of mine has the intake and runners. I was wondering if it would be worth the time and money to do something like this. Have any of you guys done this before? Pros and cons??? Thanks!

Re: TBI to TPI conversion
 

hopefully I have understood it correctly. TPI runs out of steam at around 4000 rpm,s without modification. and a properly built TBI can go further.

Re: TBI to TPI conversion
 

Keep your current setup and swap in a stock LT1 cam or even a stock L98 cam if you can find one. Just my opinion. Less time and a lot less money. Not to mention less of a headache.

Re: TBI to TPI conversion
 

Thanks guys.. I have been toying with the TPI idea for a little while now. Recently GM High Tech magazine started a 383 TPI build. I'm planning for a 400 motor. Someone I know on another forum is doing something similar to what I'm thinking. I was wondering what kind of changes, computer and wiring wise and also will my TBI fuel pump run enough pressure for the TPI? I was thinking of converting my 305 to the TPI set up, if its not much of a chore. Then when I build the new motor the TPI will already be set up on the car. Surely I will have to do some major work to the TPI intake for flow reasons. We will see if the one in the High Tech article will flow like it needs to. They are using different runners and a larger throttle body of course.
The main reason I am considering doing this is because everyone is doing the LS swaps and I would kind of like to keep an era correct intake set up on the car. Thoughts and opinions are welcome. Thanks!

Re: TBI to TPI conversion
 

I actually went from an LO3(305 TBI) to a Vortec 350 with a ZZ4 cam and TBI. Then went to a 383 TBI. And then, converted from TBI to a GM RamJet on the same 383. And honestly, I liked how the 383 ran with TBI the best. Granted I was running a bored out throttle body with the GMPP vortec tbi intake to match and 68Lb. injectors at 22 psi. As for the RamJet, I was running 36lb. injectors but it could be the RamJet is just designed for the 350. Just like TPI was designed for a 305. I'm seriously considering going back to the TBI set up on the 383 based on my experience with my setup. But ultimately you have to do what you think will make you happy. Initially you said you were thinking of converting from a stock tbi to a stock tpi which wouldn't be worh it in my opinion. The cam change is where you will see the gains and a stock LT1 cam is within the limits of the stock TBI or TPI heads.

Re: TBI to TPI conversion
 

Thanks for the input guys! Much appreciated!

Re: TBI to TPI conversion
 

no.you will have to swap in a tpi pump.however a tpi pump will work with a tbi engine.