Big Block Fuel Pump Mismatch???
Thread Starter
Instructor
Joined: Feb 2010
Posts: 150
Likes: 8
From: Pelham Alabama
Big Block Fuel Pump Mismatch???
So I bought a reproduction "correct" 40482 fuel pump off of Ebay for $70 bucks which was a great deal considering that they're like $180 from Zip/Corvette Central, etc.
Unfortunately the actual correct fuel pump for a 390hp is a 40659. Does anyone know of any SPECIFIC differences between the pumps that may hurt me?? (i.e. higher/lower flow, pressure relief, higher pressure etc.)
Here's the pumps for visual comparison...
http://www.zip-corvette.com/GroupDet...nce+Fuel+Pump&
The one that I bought is apparently for a 427 3x2 and L-88 which don't have a return line to the tank on the external fuel filter between the pump and the carb... they're just straight through to the carb. The 390hp does have a return line. Plus the 3x2's and the L-88 carb are both Holly's while mine is a Quadrajet.
Ideas??
Unfortunately the actual correct fuel pump for a 390hp is a 40659. Does anyone know of any SPECIFIC differences between the pumps that may hurt me?? (i.e. higher/lower flow, pressure relief, higher pressure etc.)
Here's the pumps for visual comparison...
http://www.zip-corvette.com/GroupDet...nce+Fuel+Pump&
The one that I bought is apparently for a 427 3x2 and L-88 which don't have a return line to the tank on the external fuel filter between the pump and the carb... they're just straight through to the carb. The 390hp does have a return line. Plus the 3x2's and the L-88 carb are both Holly's while mine is a Quadrajet.
Ideas??
Le Mans Master
Joined: Oct 2006
Posts: 7,123
Likes: 433
From: Gladstone MO
C3 of Year Finalist (appearance mods) 2019
Unless you're doing a correct restoration, just go to your parts store and get a fuel pump for $50.
If memory serves, most carbs don't really like fuel pressure much over 5-7 psi.
I've got a cheapo replacement pump on Ol' Red- crate LS-7 with some added goodies- no problems at all. No return line either.
The return line *might* help on a really hot day.
If memory serves, most carbs don't really like fuel pressure much over 5-7 psi.
I've got a cheapo replacement pump on Ol' Red- crate LS-7 with some added goodies- no problems at all. No return line either.
The return line *might* help on a really hot day.
Team Owner
Joined: Jun 2000
Posts: 38,923
Likes: 1,482
From: Southbound
Cruise-In II Veteran
Knowledge is power. Know exactly what you need before you buy.
My advice would be to sell your incorrect pump. Someone on the forum here might be looking for one.
Purchase the correct one and install it and you won't have to cap off the return line on the frame.
My advice would be to sell your incorrect pump. Someone on the forum here might be looking for one.
Purchase the correct one and install it and you won't have to cap off the return line on the frame.
