shwinny

I have curently installed my 383 and my probuilt trans. I plumbed in my mallory fuel regulator but i was thinking of going to a mechanical pump on the engine now. Do i have to drop the tank and install a pick up from a carburated car or do i need the whole gas tank from a carbed firebird. i just want it done right the first time before i go cranking the engine over. I know this fuel pump and regulator work like others have been running but i dont want to end up droping the tank in the future. while its on the jack stands minus well see if i can go mechanical and do it right.

FRMULA88

The mechanical pump installs on the passenger side of the engine block.

EFI 3rd gens, the fuel lines are on driver side of the chassis.

so you will have to redo the fuel lines with a mechanical pump.

For a carbed 383 the stock supply line & in tank pick-up are on the smallish size.


If you stick with electric pump or go mechanical pump I would re-plumb with at least 1/2" fuel line (-8AN) to avoid fuel delivery (volume) issues to the carb

you can sump the stock tank to gravity feed the pump ( either electric or mechanical) this eliminates the crappy in tank pic-up

of course if you plan to make more HP later on you should think about plumbing with -10 or -12. A larger line will never hurt performance.

five7kid

iTrader: (14)

"Smallish" as only being able to handle around 600 HP. Or, more than an mechanical pump can handle.

Keep the in-tank electric pump. It is superior to an engine-mounted mechanical pump in every way but price. With a mechanical pump, it's still a good idea to have a pusher pump back at the tank, so if you already have an in-tank pump up to the task, don't add a failure point to the system with a mechanical pump.

FRMULA88

Not sure where you are getting that information?


-8AN (1/2") for 200 to 600 HP fuel systems is the min. recommended size

The stock lines on the 3rd gen are scrawny 5/16 (not even 3/8) supply
and 3/16 (not even 1/4) return. Which is fine for a 180-225 HP stock engine.
But I would not use that as a foundation to make serious HP.

OP, Just do your homework like I did:

http://aeromotiveinc.com/wp-content/...werPlanner.pdf

http://aeromotiveinc.com/wp-content/...werPlanner.pdf


Mechanical pumps are just fine, they were used on Carbs for decades.. But like anything you get what you pay for.

I have been using this mechanical pump with no issues. This part with regulator cost more than some electric pumps and will pass enough fuel to feed up to 2,500 HP.. & is rebuild-able.

Basicly it is the only mechanical pump you would ever need.

http://www.racepumps.com/FuelSystems/FuelSystem284.swf


more info here...

http://www.racepumps.com/fuelpumps.html

But if you pay attention to these things you will see most "quality" hi-perf. fuel system products all use -8 as the minimum starting point to provide sufficient volume of fuel to the carb, float bowls.


Just remember increasing fuel pressure DOES NOT increase fuel volume.
A carb does not want more than 7psi anyway. Don't be mis-led thinking you can use the stock fuel lines and crank up the pressure to increase volume.


If you check Magnafuel or even Holley's site you will find similar information how to properly size a fuel system for your application.

A well built pump gas "street /strip" 383 can easily make over 450 HP. Mine made 465 HP 12 years ago
or 3 times the power my stock 305 made... no way the crew at GM ever designed the stock chassis, fuel system, rear end, etc. to handle that much of an increase over stock.

A track only version probably close to 550 depending on heads & cam. I went to 421.. making 680 HP.

Get the facts and do your own research, I gave you some good starting points.

Then decide what works for you..