Fuel System for Carb 408 sbc
- Thread starter Michael Bennett
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Less G forces in 3rd? Lot's of G's on launch into second then the fuel shortage hits and the pump catches back up by third? Just a theory.
If you think that’s the case, then raise the float levels and see if it’s better.
How much fuel pressure are you running at idle?
Greetings Mike & all; I used the OE return line & plumbed in a Mossoro regulating fuel log. It adjusts with various springs inserted into the check valve. As for you second 2nd gear problem, possibly the "G" force or small volume float bowl is not keep the main jets-rods covered during hard pull? That's one of the reasons many chose to run with Holley's? Ole' Bob. Ps; I ran 6-7 PIS at idle & 5-6 @ Full ON.
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You could definitely run a TBI pump and regulate that down. A stock TBI pump should be making about 20psi give it take a pound or two.But you need a return style regulator
Pushing the car through the air at high speed incurs more load than having gear multiplication through the trans at lower speed. You’re 1:1 in high gear pushing a brick at 110 mph.
Giving a call would be good idea. I looked at them this morning and other than the one screenshot I sent, all the others are 60 psi. This was true for the return and the non return style.
60 psi is the requirement for the sniper system, so could be why all the ones shown fit that requirement.
I would stick on the path your on. I was also thinking maybe 2nd gear issue, but that makes no sense. You have 5 to 6 psi and then falls to 2.5 under increase RPM??? Then it's a capacity problem.
Floats and needle/seat setups won't drop the pressure as experienced.
If any thing try change out the current mechanical pump with a new one and see if problem goes away.
Floats and needle/seat setups won't drop the pressure as experienced.
If any thing try change out the current mechanical pump with a new one and see if problem goes away.
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Good idea, I'll try that. It's and Edelbrock 800 carb so 5psi. Also, my fuel pump is only supposed to put out 6psi according to Edelbrock so I might just bypass it and see what happens too.
Hey Bob, my car was a V6 from the factory and only has the feed line on the pass side and the vent line to the canister on the drivers side. I thought about using the vent line for a return, but then not sure how to vent the tank. And yes, everyone tries to talk me into a Holley. I finally picked up a really nice used 750 vacuum secondary unit and ran it last summer when I had the 327 in the car. It ran good. With the 327, (around 300hp), there was no diff in ET between the Holley and a 600cfm Edelbrock. I might be getting to the tipping point though. I'm going to double check float levels to the high side and install some high flow needle and seats that I have but never installed to help the Edelbrock. I spent a lot of time tuning it for driveability and WOT and it is pretty spot on so I hate to abandon it for the Holley and start over.
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