casrak7

I have a gen1 sbc 388ci on the stand, ready to go, with the sniper efi kit ready to be installed. I was told that A walbro 255 fuel pump would be enough to feed this. Engine should make 535-545 flywheel horsepower with the parts it has. The factory in tank pump has a 3/8 tube at the pump for the return, and a small 5/16 line for the feed. The sniper says it requires -6 feed, and -6 return. Will this be an issue, since the feed line coming out is a 5/16 OD? I can adapt fittings and run my two lines to the front.......
Is it hard to put the walbro in place of the stock in tank pump? Never done it before, and I dont really see how the stock fuel pump can be removed from its location? Thankyou for any answers.

Gojira94

iTrader: (4)

First thing, feed side is the 3/8 and return is the 5/16. That naturally creates a restriction on return and creates a pressure differential across the fuel rail. This effect is further controlled / increased with a vacuum referenced pressure regulator on the rail. To convert these to -6AN, Earl's (Holley) has compression adapters to take 3/8 & 5/16 to -6AN male or female:

https://www.holley.com/products/plum...sion_adapters/

Narrow results by checking 3/8 & 5/16 under tube size. They're pretty cheap...

Gojira94

iTrader: (4)

As for the pump, Walbro fits in place of the stock pump, but may have to swap the factory power/ ground connector for the one Walbro uses. That may have changed since the last one I did 10 years ago on an LT1 Firebird. Do a search in the LT1-LT4 section here for "trap door" for reference on getting to the pump without dropping the rear axle.

NewEnglandFormula

that fuel system should suffice, as long as its N/A