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Looked high and low, cannot find an accurate image that show the difference in size, length, or shape of the lever arms on small block and big block fuel pumps.
I'm chasing fuel supply issues on a 454 and will be buying a new pump, but want to know what I currently have, and what I have bought in the past and see if it was right or wrong.
Hello Mel,
Thank you for the link, lines up with what I have found online.
I'm looking for detailed info on the pump arms because I have purchased Big Block spec'd pumps for this motor that didn't work well at all (454 in a 70 Chevelle, so bought a 72 large can 3 port pumps), and tried a known good 72 small block 3 port pump that worked great. So it has a Small Block pump on it now that works but has not been perfect (better than the BBC pumps before it tho). All pumps I've tried have had issues keeping up with fuel delivery, so I am now wondering if the BBC pumps I purchased before had poorly sharped arms on them, and the SBC pump I am using now has a better arm.
I want this info so I can try to find a more correct pump, as all the flow specifications and port sizes are meaningless if the arms are not correct for a Big Block.I am also going to be trying to measure the fuel pump lobe offset and therefore the push rod travel, just to make sure I am not losing the lobe on the cam.
Hello Mel,
I'm looking for a 3 port pump, 3/8 supply, inverted flare to carb, and 1/4 return, the Edelbrock and Holley pumps don't support this.
I have been looking at the Carter 6628 and 6102 Big Block pumps. 6627 shows as direct replacement, 6102 <looks> the same externally but is supposed to be a more performance oriented pump. 3 ports, big can, for BBC applications 72 and newer. Many of the specs are listed on several vendors sites as being the same, so was gonna reach out to Carter for better info.
Hello Mel,
I'm looking for a 3 port pump, 3/8 supply, inverted flare to carb, and 1/4 return, the Edelbrock and Holley pumps don't support this.
I have been looking at the Carter 6628 and 6102 Big Block pumps. 6627 shows as direct replacement, 6102 <looks> the same externally but is supposed to be a more performance oriented pump. 3 ports, big can, for BBC applications 72 and newer. Many of the specs are listed on several vendors sites as being the same, so was gonna reach out to Carter for better info.
All, I spoke with Carter Fuel Systems yesterday morning, two BBC pumps that look correct on paper (3 ports, big can, BBC for Chevelle) were the M6102 pump (70 Chevelle 454 w/Holley) and the M6628 pump (72 Chevelle 454 w/Quadrajet). According to Carter, their docs show the performance of both pumps to be about the same for a stockish street engine, but the orientation of the threaded outlet for the carb line is in question. I guess a line orientation difference between Holley feed and QJet Feed. I have read elsewhere online that the 6102 is more for hiperf, but the tech said not really. About the same pressures and GPH. So yesterday afternoon I went for it and ordered the 6628 pump. We'll see.
As for the pump arms and differences, the following pictures were shared with me elsewhere, gathered from the Holley site. So looking at each type of pump should show obvious differences, need to see if I still have the supposed BBC pump that didn't work before. I don't remember the pumps arm looking much different when I compared to a known Small Block pump prior to install.
In post 8 you said it was a 70 Chevelle 3 port now its a 72 Chevelle. They both use the same 6102 pump. Why are you now ordering a 6628? The 6102 outlet points forward, the 6628 points to the center of the car.
Hi all, sorry for the late update, sorry for the late reply. Life (health issues for family members, broken bones, and spending quality time with family) seriously changed plans. However, I don't want to leave this unclosed, so here goes.
The fuel pumps I had previously purchased for my car were expected to be '72 BBC 3 port pumps to allow using the return line (Mel is correct, 70 Chevelles have a 2 port, but I wanted to include return and couldn't cost effectively get a return port filter, hence the '72 3 port pumps). Purchased thru my buddy at O'Reilly's, who understands the car is 454 equipped, the purchase info shows request of BBC pumps. However, when removed and compared to the aforementioned Carter pump I ordered in, the arms were the shorter type used on SBC pumps, hence my issues with fuel delivery and bogging. Don't remember what brand, was the store brand.
So, I ordered and many months later finally installed the correct BBC pump, and all issues went away (as expected). However, the carb on the 454 in my wagon has the choke set fully open all the time (SoCal, never really cold, so, eh.), which with the previous pumps was sometimes an issue. With the new correct pump, the motor starts well, even cold without a choke. Drivability is great, runs like a Big Block Chevelle Wagon.
So, closing thought? Issues with drivability in a Big Block powered vehicle that you don't know or aren't sure about the history of the pump, or issues after you replace a pump on a BBC, maybe check the pump arm. For sure I'll compare old with new when replacing a Big Block pump.
And I am working on return of the incorrect pumps.
SBC vs BBC fuel pump identification
