I have a 1977 chevy350 that I am modifying with TBI the intake is 1991 and I want to know if I need to use the oil pressue sensor from the 1977 engine or the 1991 oil pressure sensor , as it is right now the new one does not seem to fit into the same hole in the block as the old one , and from what I have been reading it is pretty important to the setup to have the sensor hooked up. Thanks Dan

also any pics of someone with this setup would help me out tremdously thanks

I don't have any pics but use as many of the sensors as you can for your aplication. I did the same conversion on my blazer, I managed to get everything on mine but the VSS, not a big issue but it will turn on the "check engine" light every time you drive your truck, I didn't mount my light. But back to your question the tbi oil pressure sender needs to be hooked up, if nothing else but to protect you form your self and help your engine live so that you don't run it for an extended period of time without oil pressure, I've only managed to make it shut the engine down one time and in that prediciment I needed something to tell me it was time to ask for help.

if this is a sensor for the ecu, then u need the new sensor.. i don't think an old oil pressure sensor would send to the computer right.. old oil pressure senders would be only for guages.. i know on my motors it takes 2 sensors for things like that.. one to run the computer and one to run a guage.. this make sense?? did i misread your question?

In my 1990 camaro svc manual the oil pressure switch is connected to the fuel pump relay and will kill the engine if oil pressure goes too low. Maybe thats the only difference?

TBIs do NOT use a oil pressure switch to shut down the motor if the oil pressure is low. The switch is a failsafe for when the fuel pump relay craps out. It is redundant, but valuable, as the relays do die occasionally. After cranking for a little bit, the motor builds up enough oil pressure, the pump comes on, and the motor starts. Note TBI motors used 2 senders, one for the gage (large can mounted near the filter, with one wire (on R/V series, at least)), and the one described above (located near the distributor, on a 90° elbow, with a funky-shaped 2 prong connector).

Pete

ya that makes sense that I would need both , I was just wondering if anyone had ever delt with it before. Because I got the new part and on this old block there does not seem to be any place that it will screw into.