Ok so a lil back story, I have a 1987 sport coupe. When I bought the car it had a carbed 305 with a mechanical fuel pump. The motor I swapped in (carbed 98 vortec) does not allow for a mechanical fuel pump.

Now if I understand correctly, gm started using electric intank pumps in 1987. If that is in fact the case would it be safe to say that the engine that was in the car was not stock?

And if that's the case, would it be possible to utilize that intake pump with a pressure regulator? Rather than buy a inline electric pump.

 

No, in '87 the LG4 had a mechanical pump mounted on the engine, and a "pusher" electric pump in the tank. The purpose was to mitigate vapor lock problems. The factory offered a dealer-installed kit if a customer complained about vapor lock for the earlier years, which included the in-tank electric pump. They made it standard for L69 cars either late in the '83 or '84 model year (haven't been able to determine when it was exactly - reports vary), and for the LG4 in '87. But, they always used the mechanical pump on the engine, even with the in-tank electric, for carb'd cars.

The factory in-tank pusher pump isn't enough to feed the engine by itself. So, drop the tank, pull the pickup assembly, and put in a better pump (a replacement TPI pump, or Walbro 255, are popular choices). Use a return-type pressure regulator like the Walbro 4309 or Holley 12-803BP (has to be the "BP" version - there is also a 12-803) or similar.

 

Thank you for the detailed advice five7kid. If I get a stock TPI pump will it plug right in or would there be wiring involved?

 

I believe it will plug right in. But, the pump size may be different. I don't know off the top of my head if mods are required to the pickup. Sorry. Shouldn't be too big of a deal, though.