Ok, first, I really hate to post this with the vast amount of threads on engine swaps, but I cannot for the life of me find someone in my situation. I am swapping the LG4 with a 350 Vortec out of a 1999 Tahoe. On the new motor there is no provision for a manual fuel pump, which takes me out of the 50% of posters here and I also am not starting with a V6 or 305 TBI, which takes me out of the other 50% 
To the question. What would be the BEST way for fuel delivery? I obviously can't use the manual, so I am left with the in tank electric. I plan on making about 375hp with the motor which I already rebuilt (lt4 cam/headers/EQ vortec heads/670 carb). Would I be right in saying that the stock in tank electric for the LG4 would not supply enough fuel on it's own? Should I scrap the in tank pump and just go with an electric in-line (my concern is in-line is too loud as this will be a cruiser)? Would the fuel pump out of a fuel injected or TBI model be more powerful and I could just use the existing lines with the special bypass regulator that feeds back to the tank? So many ideas, was just wondering what your guy's thoughts were. Thanks in advance for any advice!
P.S. Will the oil pan from the Tahoe motor fit in the Firebird? My friend and I have been debating this for too long, haha. Thanks!
To the question. What would be the BEST way for fuel delivery? I obviously can't use the manual, so I am left with the in tank electric. I plan on making about 375hp with the motor which I already rebuilt (lt4 cam/headers/EQ vortec heads/670 carb). Would I be right in saying that the stock in tank electric for the LG4 would not supply enough fuel on it's own? Should I scrap the in tank pump and just go with an electric in-line (my concern is in-line is too loud as this will be a cruiser)? Would the fuel pump out of a fuel injected or TBI model be more powerful and I could just use the existing lines with the special bypass regulator that feeds back to the tank? So many ideas, was just wondering what your guy's thoughts were. Thanks in advance for any advice!
P.S. Will the oil pan from the Tahoe motor fit in the Firebird? My friend and I have been debating this for too long, haha. Thanks!
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Originally Posted by vwjet2001
Would the fuel pump out of a fuel injected or TBI model be more powerful and I could just use the existing lines with the special bypass regulator that feeds back to the tank? After going through 4 inline pumps (mounted correctly), In my research on my GMC truck, I found the in-tank MPI fuel pump runs a higher pressure than a TBI pump. I didn't feel comfortable choking down a MPI pump in fear of burning it up (too much back pressure), So I went with the TBI pump and return regulator as you stated. It runs my BB 502 with no issues at all.
Don't know about the truck oil pan but I'll be finding out first of the year.....
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Night rider327
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May 9, 2024
Holley blue elec inline fuel pump or carter elec. in line pump. (Carter elec. is a good bit quieter than the holley)
Use thick rubber pads between the pump and mount point on car
Mount pump at rear of car, below fuel tank. Use your same lines and what not.
The holley blue pump comes with a dead head reg. and does not need a return system (return is always good to have though)
MANY, MANY cars have used the holley blue or carter elec inline pumps with no probs what so ever.
Probs with inline elec pumps happen when you try to use the little cheap square body 35 gph mr gasket and other brands elec pumps. Or when you try to mount an elec in line pump under hood away from tank.. They work well as a pusher, they don't work as a puller. So if you mount the pump under the hood, it trys to pull the fuel all the way from tank to pump and just can't do it.
Use thick rubber pads between the pump and mount point on car
Mount pump at rear of car, below fuel tank. Use your same lines and what not.
The holley blue pump comes with a dead head reg. and does not need a return system (return is always good to have though)
MANY, MANY cars have used the holley blue or carter elec inline pumps with no probs what so ever.
Probs with inline elec pumps happen when you try to use the little cheap square body 35 gph mr gasket and other brands elec pumps. Or when you try to mount an elec in line pump under hood away from tank.. They work well as a pusher, they don't work as a puller. So if you mount the pump under the hood, it trys to pull the fuel all the way from tank to pump and just can't do it.
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Nice, thanks for the info! I guess that brings up another question. Would the MPI or TBI pump just drop into the current carriage/fuel sending unit from a carb model pump? I know the tanks were a little different with the baffle for the fuel injected models, but haven't found much info on the sending units.Originally Posted by Restrorob
After going through 4 inline pumps (mounted correctly), In my research on my GMC truck, I found the in-tank MPI fuel pump runs a higher pressure than a TBI pump. Senior Member
You can't mount a fuel pump to a carb sending unit, you need the complete TBI sending unit-pump assembly, I don't know if there's any difference in the fuel tank it's self or not on these cars. In the case of my truck, It had a MPI tank/sending unit and I had to replace the tank with a earlier TBI tank/sending unit.
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Ah, well good to know, thanks! I have to buy a new tank anyway as the current one has a small dent/crack in the bottom from a gravel rock or something. So in this case I would buy a TBI tank/sending unit, use the existing lines, install a regulator with a return line up front and I should be good? I am assuming the TBI sending unit is compatible with my current fuel level gauge...Originally Posted by Restrorob
You can't mount a fuel pump to a carb sending unit, you need the complete TBI sending unit-pump assembly, I don't know if there's any difference in the fuel tank it's self or not on these cars. In the case of my truck, It had a MPI tank/sending unit and I had to replace the tank with a earlier TBI tank/sending unit. 
Member
You wouldn't have to replace the sending unit.
I converted my 87 to carb, motor that was in it had provisions for a manual, but for WHATEVER reason, it was welded closed. I used a "spectre" performance inline one, mounted it in line just above the tank. I cut the metal line where the sender connects to the body fuel line to engine and installed there.
Then in tank, remove the pump, get a piece of submergible rubber tubing on the end, and for a filter I just used one of the clear carb fuel filters and just stuck it on the end of the hose. Just make sure the filter reaches the bottom/back of the tank where the pump would originally sit.
Had zero issues.
I converted my 87 to carb, motor that was in it had provisions for a manual, but for WHATEVER reason, it was welded closed. I used a "spectre" performance inline one, mounted it in line just above the tank. I cut the metal line where the sender connects to the body fuel line to engine and installed there.
Then in tank, remove the pump, get a piece of submergible rubber tubing on the end, and for a filter I just used one of the clear carb fuel filters and just stuck it on the end of the hose. Just make sure the filter reaches the bottom/back of the tank where the pump would originally sit.
Had zero issues.