Carb swapped ‘97 vortec - SUCCESS!!!

[Supercharged111]

You can't do that with a pump designed to run at 4 bar. If using an EP381, you need the dual stage bypass like the one he bought. If he had put in a TBI pump when he cleaned the tank and replaced the pump... then he could have used the holley or similar bypass regulator to get the right PSI without killing the volume. It's really doing the same thing, but he just ended up spending double. The only reason to use the double regulator setup is so that you can keep the rest of the fuel system stock. The second he was going to need to replace the pump anyways, he got the opportunity to move to a lower PSI in-tank pump and save money on the regulator. At this point, he is already committed to needing to step down the high PSI because he already put a Vortec pump in it. The only benefit is that he won't have to replace the pump if he goes to a 5.3LS in the future. The downside is that if he does, the regulator he has won't be needed anymore.

I beg to differ. I used a Mallory regulator on a 92 Crown Vic to choke the factory pump down to 6psi for an Edelbrock carb and it worked like a champ. Single stage.

 

[GreenMonkey]

So after seeing pictures of other people with a carb swap I’m wondering if something is off with my truck based on which way my distributor is facing. The truck runs alright (still learning carb tuning) and I have it set at 17 degrees initial advance without the vacuum advance hooked up. But my distributor faces a totally different direction than the others I’ve seen. What do you y’all think?

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Like Erik the Awful said, you can clock them any way you like. The way I’ve found that works best for adjustability without having the vacuum advance canister interfere with the firewall or intake is to have it clocked about 90 degrees counterclockwise from how yours is.

 

[Jerryred94silvy]

On a small block Chevy you can clock the distributor housing any way you like and it will run, so long as the timing is correct.

Thank you! I’m having to unhack the hackery that the engine builder and my highschool self performed. Fun times lol

 

[Jerryred94silvy]

Like Erik the Awful said, you can clock them any way you like. The way I’ve found that works best for adjustability without having the vacuum advance canister interfere with the firewall or intake is to have it clocked about 90 degrees counterclockwise from how yours is.

I’m not entirely sure how mine ended up the way it is now, but if it becomes too big a pain in the rear as it is then I’ll re-clock it. But for now it works well enough, I’ll put the hassle off for later.

 

[BeXtreme]

I beg to differ. I used a Mallory regulator on a 92 Crown Vic to choke the factory pump down to 6psi for an Edelbrock carb and it worked like a champ. Single stage.

You were probably right on the edge then or didn't have much HP. A 92 Crown vic stock pump is designed to runs on 35-40psi, so more like a late BBC TBI pump. It's a little bit better, but still terribly inefficient and you are cutting a lot of volume doing it that way. As long as the volume being provided is sufficient for the HP being made, it isn't a problem.

He's working with a stock pump that is designed for almost double that pressure. The volume lost is going to be much more than what you lost with that crown vic, and the engine is likely going to be needing more than you did as well. The real problem is that you are going to have a hard time calculating just how much the loss is going to be and whether you are going to be able to supply enough through the single stage regulator until you are running out of fuel at full throttle and the engine goes lean.

 

[Supercharged111]

You were probably right on the edge then or didn't have much HP. A 92 Crown vic stock pump is designed to runs on 35-40psi, so more like a late BBC TBI pump. It's a little bit better, but still terribly inefficient and you are cutting a lot of volume doing it that way. As long as the volume being provided is sufficient for the HP being made, it isn't a problem.

He's working with a stock pump that is designed for almost double that pressure. The volume lost is going to be much more than what you lost with that crown vic, and the engine is likely going to be needing more than you did as well. The real problem is that you are going to have a hard time calculating just how much the loss is going to be and whether you are going to be able to supply enough through the single stage regulator until you are running out of fuel at full throttle and the engine goes lean.

Only 1 way to find out.

 

[GreenMonkey]

Wanted to report back about the fuel pressure regulator. I initially tried using a single stage Holley billet regulator and it was unable to get the fuel pressure under 12 psi to the carb. So I installed a dual pressure regulator and it works perfect with a new factory style pump. Got it timed, tuned reasonably well, and took it on a drive today. Everything seems to be running as it should. Will clean up the unused wiring as I have time, but at least it’s driveable.

 

[Moleman]

How is a Holley with vortec heads I went Edelbrock 750.

 

[Sean Buick 76]

Nice to see some carbs getting sone love!

 

[GreenMonkey]

How is a Holley with vortec heads I went Edelbrock 750.

Mine's running well. I'm sure there's not much difference in performance since they're both reputable carbs. The truck was underpowered before the swap, and its still underpowered with the holley. But at least it runs and starts better than with a worn out fuel injection system.