First off I want to let all of you know that this was my first choice on looking for knowledgeable bodies when it comes to TBI/TPI ecm systems. Here's my idea in a nutshell. I just aquired a 21' 350 powered runabout boat and with my knowledge would like to implement a reliable TBI EFI setup on it. The only GM ECM in my mind that would remotely tolerate this type of environment would be the 727 ECM. It appears that the 727/730 was even used with a TBI application and not just running batch port injectors. Where to start with this exactly? Would the $8D mask be wrong for a TBI application? Is there another mask that would be better suited for this? And how hard would it be to create an open loop only tune that would work for a boat engine application? Any thoughts, ideas, or concerns? Let me know what you think..

 

727/730 ECM will not work with TBI.
Only one driver for injectors
It has been tried

 

So on the TPI it has one driver that fires all 8 injectors at once?

 

Yes 1 driver.

I believe it will fire one TBI injector.
Stock on a 4cyl IIRC.

If you have room, use 4 to 8 saturated injectors installed in
a spacer plate beneath the TB.
Just make the injectors big enough.

They also make a marine version of the vortec dual plane intake with port injectors IIRC. Then just use the 727.
They show up on ebay occassionally.
There's a pic floating around on ALt intakes board I think.

You could also look into adding a second driver set from a spare 730 or swapping parts onto a 749 board to fit the 727 case.

Do a search on 8708, it might have a second driver and comes in a outdoor case version.

 

how would a tpi intake do for a boat power plant? I would think for its torque qualities and low rpm usage it might be very suitable.. I will just have to convert it to a closed cooling system to make it last. what considerations would i need to make on tuning it with a 727?