Best way to Modify tank for larger pickup?
 

I'm replacing the stock 454 mag with a 530hp 6200rpm 440, and need to know what the best way is to enlarge my fuel pickup? It's an aluminum tank with a screw in 3/8 pickup tube, and I figure I need to step up to at least 1/2" if not 5/8" just for good measure. I can't pull the tank without completely cutting it out and removing the floor. Am I wrong in thinking the only way to do this is to cut a hole in the top of the tank, and bolt down a plate over it with a larger bung welded on? What's the best way of doing this without getting tons of shavings into the tank, or the best way of removing those shavings?

If a 3/8" Inside diameter pickup will fit as it is that is enough fuel for 575-600 hp so I wouldn't worry.

Agreed, leave it alone until you know its a problem

I thought 475-500 was the limit for 3/8? I'm running -8 to everything, and don't want the pickup to be my choke point. The engine has yet to be installed, and I don't have enough room to change anything once it is.
Here are the Engine Specs

440 Cubic Inch BBC 525 hp @ 6000 rpms

Block-
Decked
Align Honed
Bored .060 over
Steam holes drilled
Bore notched

Rotating assembly:
GM Forged Crank, NOS 3.76 Stroke
Eagle H Beam Rods- Resized at Wesco
SRP Forged Domed Pistons
ATI Super Damper

Valve Train:
AFR 265 Oval Port Heads CNC Chambers, inconel Exhaust Valves
Morel Roller Lifters
Scorpion Endurance Marine Rockers
Marine Kinetics Roller Cam
234/240 .63/.61

Fuel System:
Weiand Stealth Intake
Pro Systems HP Holley, 830 CFM
Holley Marine Fuel Pump

Can you post a photo of the existing pickup and tank bung?

Merc 900's only have -10 feeding them. Most hp 500 and 525 boats have 3/8. As Marc said, best bet is to post a picture to be sure.

The boat is about an hour away, and I don't know when I'll be able to make it out there, but here is a pic of a very similar pickup tube although on mine the tube isn't welded to the fitting, it looks to be threaded in, and the bung is just welded to the top of the tank.

This is the only pic I could find that even shows the tank, and it's before all the work I've done so please excuse the mess
http://im1.shutterfly.com/media/47a3...D720/ry%3D480/

and here is the pic I mentioned in my prior post but forgot to actually post.

http://im1.shutterfly.com/media/47a3...D550/ry%3D400/

A -8 is enough to support up to 800hp on e-85! But it's always good to check everything while your in there!

We run the stock 1987 Wellcraft pick-ups with almost 800 HP NA. My guess is they are 3/8" as they are original and the boat had the Merc 370HP new. We also run -6 lines from the tank thru the fuel cut-offs and then to the fuel/water separators. We have -8 SS braided from the F/W separators to the carb...why?...bling. We hold 7lbs of fuel pressure at WOT. Just the facts, not opinion. There are lots of ways to improve preformance in your boat, but larger fuel lines won't add anything but cost. As long as you can hold 6.5 of fuel pressure at the carb fuel rail, you are good to go.

So is the stock 3/8 fuel water separator fine then as well?

It s highly likely a 3/8" fuel line system is adequate. If you are concerned, rig a temp fuel pressure gauge at or near the carb to confirm your FP at WOT.

I would throw your pickup tube in the trash. When you screw the 3/8 pipe fitting into the elbow on that tube it creates a very small are for the fuel to take its turn out of the top of the tank. I always use a 5/8 pickup tube. Thread the end of the 5/8 tube get a -10 ORB to -10 fitting tap the ORB side of the fitting to match the thread on the tube. I like fine thread cause you get more are of contact and its stronger. Then I drill the bung in the tank with a 3/4 drill bit and tap to 7/8-14 then screw the new tube in. I've done a bunch this way for myself and others and it seems to work pretty good. The hardest part is getting the die started on the stainless steel tube. Usually alot easier if you have a lathe handy...

While building my 496, I wanted to see the fuel supply from the tank. Here is what I found, good thing I looked. The plastic tube with the screen had fallen off, I had to fish it out the fuel sender hole.

http://i283.photobucket.com/albums/k...r/IMG_0048.jpg

We took a -8 90' 3/8" fitting, reamed it to fit 1/2" fuel tubing and pressed it in with locktite. So far has worked great for 2 seasons.

http://i283.photobucket.com/albums/k...r/IMG_0049.jpg

-Tom.

I don't run fuel water seperators either. Shouldn't be putting water in your gas tank anyhow. Fuel water seperators end up putting air bubbles in the fuel if you have a motor that demands alot of fuel they do not flow very well. There are some good one out there but they run around $600. I run an inline 10 micron filter. When you setup a fuel system 90 degree fittings are a big no no. They drastically cut down the flow of the system...

As mentioned, the fitting size isn't the problem. The problem is the small hole in that pickup where the tube meets the 90* square fitting on top. Once you screw the adapter fitting into it, you end up blocking off some or most of the hole. I have seen them where you are left with only about 1/8" hole once the fitting is screwed into it. We have just been making our own pickups. I use a 3/8"NPT x #10 SS fitting. I bore the 3/8" side out to the same ID as the #10 side. We use SS since the aluminum can become rather weak once bored out to #10. We then Tig weld a piece of 1/2" ID SS tubing to the fitting. We have been using them for over 10 years and they work great. Let me know if you would like one. I would be glad to build one for you. Here are some pics of our pickup along with a similar pickup to what you have now.
Eddie

Eddie,

How big of efi motors do you run on a pickup like that?

We have done 1000 hp with the same pickup. This exact one went in a boat with 945 hp.
Eddie