I have a 1974 Barracuda with a 1969 340 engine that I'm looking to upgrade to MSD EFI Sytem.

This is an expensive venture, so I want to only do this once and right. I'm looking for feed back on if I'm missing anything.

I currently have a 3/8" fuel supply line, mechanical pump and 1/4" vapor line. Tank is vented and I have a vent gas cap already.

I'm planning on removing the mechanical pump, Charcoal filter, modifing the gas tank and installing a Walbro pump in the gas tank, reuse the 3/8" supply fuel line, install a gauge and fuel regulator and pipng under the hood, using the 1/4" vapor line as the fuel return line back to the tank and installing a vented gas cap. The vent on the pump will be capped at the gas tank bacuase I would have the vented gas cap.

Has anyone done this or is there anything I'm not considering? I want a reliable fuel system and am will to spend the money up front to avoid the tow truck later. I think this would be the best setup based on other information I've found. Any thoughts? Thanks!

Here's a bump. I'm looking at doing the same as you but as of today I still have not pulled the trigger. I'm trying to decide which system I want to use. If you are looking at the MSD Atomic system then you also need to consider the FAST Easy EFI setup. Lots of reading........

That is pretty much what I did with my EFI set up, except I ran a 5/8 and 3/8 sending unit, 5/8 for feeding the injectors and 3/8 for the return line, as my motor is putting out over 500 hp. Works great, no fuel staring issue.

The MSD has a lot of +'s but since they also have a forum, there are a lot of posts from people with problems. I've yet to find a FAST forums so one can't just assume that these are trouble-free!

The thing I like about the MSD versus the FAST is that it will handle a bit more HP, fewer connections AND the ability to use timing control, although a couple of mechanic friends are wondering why you'd want that.

I just wish they hadn't tried to make the thing look like a carb !!

This is a throttle body EFI and still has many drawbacks of a carb. OEM's quit using throttle bodies years ago for good reason, port fuel injection is MUCH better. If you're going to spend the money on EFI, you really want port injection. Yes it does cost a little more because you need a special intake manifold and 8 injectors....but then you have all the benefits of EFI not just half of them.

A friend installed the MSD Atomic on his Superbird last year. I think it is nice that you have to look hard for it to see it.

So far it is a mixed bag, but it is still early days. The car lights instantly which is pretty cool. Fuel mileage was not improved at all. Driveability has improved as the system has "learned". It had a bit of off idle stumble, but I hear it has gotten better. He is going to move the fuel pump into the tank as he experienced a vapor lock issue with it mounted just inside the rear of PS rocker panel.

Overall the system has not been a rousing success, nor has it been a failure. But it was expensive. We will see how it goes this year.

ECU mounting.

The system was very straightforward to install. No drama.

Here's the FAST support forum.

http://www.cpgnation.com/forum/fast-product-support.html

They are not without their issues as well but one advantage is we have a member here, Rich Nedbal who sells and supports the FAST lineup. He provides excellent support and you can check out his website at www.fastmanefi.com .

Engine is a pretty fresh, mildly enhanced 440. The car is a driver.

I believe you biggest issue is the return line size. Common sense says otherwise, but the 1/4" vapor line inhibits proper operation of the regulator, causing intermittent problems. If motor is mild, it might better to use 1/4" as supply, up the pressure a bit.

Any EFI's guru's concur?

are just add another 3/8" and forget about it.

Scrap that 1/4" line. Upgrade the return to whatever size your regulator is designed for. I used a GM LS1 filter/regulator and that's designed for 3/8 supply and 5/16 return so that's what I used. Go too small on the return side and you risk the pump overwhelming the regulator resulting in incorrect and inconsistent fuel pressure.

can you use this system with dual plane manifold?

Yes, it might even work better than a single plane.

I have the Atomic. I think it may be the best thing I have ever done to my Mopar, well next to the 480 ci HEMI.

Keep in mind if you put the pump in the tank you will need to baffle it or run an external reservoir. The pump will pull air causing a lean condition on low fuel levels around corners. Also you will need a bigger return line usually the same size as feed line.

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or run an external reservoir

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Huh ?!?!? What good does that do if the pump pulls air?

I used these guys ( http://www.radiumauto.com/ ) surge tank. They make nice stuff.

Thanks for all the advice. I will change out the 1/4" vapor line and install 3/8" return line. The 3/8" line feeds sufficient gas to my engine. The engine puts out 415 HP on the Dyno. I don't want to install a true EFI because it really clutters up the engine bay. I'm just looking for better running, faster response and more HP. I like the MSD because you don't see much and everything else in the car is MSD. Also how easy it it to install. The pump in the tank will have a baffle around the inlet. Plan on getting it from Tanks Inc along with the tank recess.