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Here's the deal. I installed an 87 Iroc 350 into my 91 FWB. Converted to carb. Car runs great but I'm having trouble with the fuel pressure. I installed a Mallory fuel pressure regulator and adjusted it to around 5 1/2 lbs pressure. Problem is it does not stay there. Upon startup it goes as high as 9lb and after it warms up it goes as low as 2lb of pressure, what gives?. I am constantly adjusting the damn thing but it seems to have little to no effect on the way the car drives. Actually, at times it feels like it has more power than other times. Does the fuel pressure have to remain constant or is this normal? Also the fumes really are overwhelming. I've tried to adjust the air/fuel mixture on the Edelbrock carb but it always seems to emit a funky smell, especially when at a stop light. Anybody know a good way to tune the carb?. Any help would be appreciated.

One more thing, the carb conversion seems to have totally changed the sound of the car. With the TBI it sounded awful.....kinda raspy like a red neck pickup truck w/glasspacks and now it sounds kinda like a 5.0 Mustang. Its got true dual exhaust with Magnaflow mufflers. I'm not complaining about the sound, it sounds great, kinda like a true musclecar should sound but I'm really stumped as to what caused this change in sound, it sounds totally different (but better).
 

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I was having problems with my #1407 Edelbrock when I went to high altitude (>6000 feet), even though I was jetted for it, the fuel was boiling in the carb and forcing its way through the boosters, but only at idle (70F out). I eventually put on a multiple stack carb spacer for heat and that helped, but ultimately the blockoff of the exhaust xover fixed that problem. It was on a 70 10:1 compression 455 Pontiac with a Cam Dynamics 284H cam (.480 lift, 228 @ 0.050, on a 112). Small valve iron heads with Edelbrock Performer intake.

As for fuel pressure. Are you measuring at same engine rpm? Do you have electric fuel pump or mechanical? Mechanical needs to be at x rpm, electric doesn't matter. Do you have a return on the regulator? If no return, it will eventually overpower it and raise pressure.

Even 2 lbs should live on a Q-Jet, but WOT may be an issue. Q-Jets will put up with as high as 7 lbs, but are designed around 5.
 
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N0DIH said:
I was having problems with my #1407 Edelbrock when I went to high altitude (>6000 feet), even though I was jetted for it, the fuel was boiling in the carb and forcing its way through the boosters, but only at idle (70F out). I eventually put on a multiple stack carb spacer for heat and that helped, but ultimately the blockoff of the exhaust xover fixed that problem. It was on a 70 10:1 compression 455 Pontiac with a Cam Dynamics 284H cam (.480 lift, 228 @ 0.050, on a 112). Small valve iron heads with Edelbrock Performer intake.
As for fuel pressure. Are you measuring at same engine rpm? Do you have electric fuel pump or mechanical? Mechanical needs to be at x rpm, electric doesn't matter. Do you have a return on the regulator? If no return, it will eventually overpower it and raise pressure.
Even 2 lbs should live on a Q-Jet, but WOT may be an issue. Q-Jets will put up with as high as 7 lbs, but are designed around 5.
Its the stock fuel pump for a 91 Brougham w/305. I'm running an Edelbrock carb. The regulator does have a return line. I'm measuring the fuel pressure at idle and it varies. Can I damage anything when its running between 8-9lbs? Pressure seems to go down after startup and settles at around 2-3lbs after driving it for awhile. I know the Q jet is ok at 2lbs but is an Edelbrock good at that pressure too?. Thanks.
 
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