so i just put my newly rebuilt 1972 355 in my 91, and my dad and mechanic said i have to run a pickup where the fuel pump is. i really dont want to drop the tank i kinda want to start the car this weekend. does anyone know the exact location to cut the access door from above the tank. and have pics of it? any help would be greatly appreciated.

 

https://www.thirdgen.org/forums/faq-...tal-above.html



This is not my car and I have never done it so I can't verify measurements.

If you do go this route this radius the corners so it doesn't want to tear. You will also need to cut the lines and splice them back together ( I believe). The thread covers it. Summit carries nice access panels to finish off the door for around $30.

Why not use a Mallory 4309 regulator [return style]? I'm using one for my carb and I'm still running the FI pump.

 

This is what im using without any problems.

The best/cleanest access panel I have seen it this one. Not a thirdgen, but you get the idea.

 

That looks like one of those doors fom all star performance. I was thinking about using one to clean up the hole someone before me cut in my car

 

my dad has it brain washed in his mind to run a pickup. so im not arguing. i just dont wanna drop the tank

 

a pickup for what? your using a mechanical pump? Just use the factory pump setup with a adjustable regulator like listed above, its a much better and easier method than dropping the tank or chopping a huge freaking hole the car, i mean, its a simple fix, why go through all the effort to "rig" something?

besides, since the car was originally fuel injected, the fuel lines are on the driverside of the car, the mechanical pump is on the passengerside....so you will end up with fuel lines zig zagging all over the engine bay. Thats a recipe for disaster and will look terrible.

just remember, you need to reuse both the fuel lines, the feed and the return, for either pump setup. With the mechanical is helps with vapor lock issues that 3rd gens with carbs are notorious for, and will keep the electric pump cooler.

 

If you do cut the access hole you should use a hole saw for the corners, that would help stop the cut from going farther over time. Also the body is so thin a good pair of tin snips will cut it, you really don't need power tools except for the hole saw.

 

actually its tbi and i dont want to risk the electronic pump failing while im racing down the quarter mile. a mechanical one is less likely to fail

 

It's a good thing all of today's car manufacturers stood with the mechanical fuel pumps, I mean, could you imagine everyone breaking down on the highway during everyday commuting with their electrical intank units lol....?

Just mark your area, then make your cut using a powerdrill w/cut off wheel. It is very simple. I only did mine because I was under the impression that most, if not all, L69's had an electric pump used in conjunction with the mechanical pump to assist w/vapor lock. Worked to my advantage though because now pump swaps will take me twenty minutes taking my time. Mine is on page nine of my build. Good luck with whatever route you choose....

https://www.thirdgen.org/forums/powe...d-305-a-9.html

 

Dude....seriously? Who fed you THAT line of BS?

 

They might not fail that easy but the mechanicals are way cheaper and quiker to swap out

 

thank you i like running mechanical due to its cheaper. i can replace it easily and it looks good. and mr64 im 18 and just dumped $2000 into building my motor i know what im doing and would appreciate if you were professional . i dont go around saying what you say is BS do i?

 

Well, whether you want to hear it or not, you're wrong.

The electric pump with a bypass regulator is more reliable and will feed the engine better than trying to suck through the stock lines with a mechanical, there's a reason why electric replacements for mechanical pumps existed well before FI, because mechanical pumps would fail in all sorts of ways and just couldn't feed serious engines. At the few PSI that you need to feed a carb the FI intank pump will move more fuel than anything but a $$$$ mechanical, and the mechanical pumps that really are reliable and move fuel are a different design then a stoker.

 

Sooo......you just put 2 grand into a motor, and your putting in a mechanical pump cause its "cheaper"........ok...

 

yeah i kinda hit my limit and im broke i had bought the car for $3000 and saved up. bought the corvette motor for $600 and and spent the remaining $1400 in everything else i did. now im broke and want to take the cheaper way out. a cheap way that ive been told by various mechanics works just fine till i decide to drop in a $200 fuel pump. its not like im dumb this is just a temp fix so i can drive the car. i havent driven the car since feb. https://www.thirdgen.org/forums/imag...es/driving.gif

 

the problem is that you're running tbi - a "cheap" mechanical pump will not put out the pressure you need to feed the system. they're only good for maybe 8psi, where the tbi setup is about double that. If you went mechanical, the stock pump has to be pulled out of the sending unit and the sending unit has to be modified with a pickup so that you can suck the gas out of the tank (otherwise nothing's coming out of the tank).

furthermore, due to the design of the sending unit, the lines snake across and down the tank, not something you can access (in stock form) through a hole in the floor. Now, if you dropped the tank down and had the sending unit modified correctly/safely, the the access door is feasible.

now i am one who is all for adding an access door, but only if done right - flared fittings on the sending unit and a reinforced access door.

either way, to do this correctly and safely, you need to drop the tank. you should never cut that close to the tank and there's not enough room to properly modify any of the lines. Dropping the tank stinks, I know, I just did this over the weekend myself. but it is doable on jackstands with basic tools and is not as intimidating as most think

 

Man this is a frustrating thread...

I'm going to leave it at:
- most "mechanics" don't have much of a clue past swapping OEM parts. The fact is that I haven't seen you repeat much that doesn't sound like bad advice so I can only conclude that they either fit that category or you're not repeating back everything they're saying.
- I am not into half assing things- that being said, I don't see any good reason to drop the tank to get to the top of the tank
- I fail to see any way that you're going to do what you're talking about doing for cheaper then just buying a cheap bypass regulator (actually, I suspect that parts to put a carb style pickup... will actually cost you more than some of the more expensive bypass regulators).
- this all assumes that you're running a carb on this thing, if you're runnning the stock TBI or any other FI the mechanical pump won't work at all.
- I don't have a clue how you feel safer about running a mechanical pump, desgined to supply barely enough fuel to power a stock engine at roughly 3 psi then an electric pump that will supply more volume at many times the pressure (flow goes up at lower pressures, so if you're asking it to supply less pressure at the regulator you'll end up with much more flow).
- running the stock intank with a bypass regulator will get you on the road the fastest, for the cheapest, and the most reliably, will prevent any tendencies towards vapor lock or other problems that mechanical pumps/carbs tend to have...
- If I did replace the stock pump with pickup in the tank I would still use an inline pump and a regulator instead of the mechanical, block mounted pump on any performance application.

 

You keep saying you want cheaper. Well, doing something ONCE is the cheapest way. In other words, don't blow $ on a band-aide stepping stone only to spend more $$ later.

Just wait & spend the last amount ONCE & you'll have saved the $ from doing the band-aide/temporary step. All it takes is patience. And I know at 18 yrs old, that it a rare commodity but will serve you will if you start now.

 

I agree. It took me 3+ years to build my 383 because I was making ~$400 per month while going to college and now I'm still in the process of getting it all tuned up and running again.

In the end it's your car and no one else should tell you one way or the other. Everyone has to do make there decisions for themselves in the end. Modding stuff is part of the fun with these cars.

 

well i cut the access door and everything went fine. also ran new fuel lines fot the carb. i did drop the tank far enough to cut with out risking danger. i went with the mechanical cause it was brand new on the block when i got the motor. its a high performance holly. so i spent $8 in fuel lines and $4 in a metal pipe to make my own pickup.

 

not tryin to seem like a hillbilly lol, and NO i didnt do this to my car (i kept efi) but on my buddys 87 iroc, he put a 383 in it and went the carb'd route. so instead of droppin tanks, and buying regulators and such. he just let his mechanical pump pull through the return line......thats some outside the box thinking hahaha. i know whatever is inside the tank isnt properly bieng "strained" but he put an inline fuel filter before pump, and after pump before carb. works fine, and holds a steady 12-13 psi.this isnt for everyone (including me) but it does work. and works fine. kinda hillbilly, and corner cutting. but you seem to want to cut this last corner, so try it out. OH!!! and cutting a hole in your trunk to access the fp, IS HILLBILLY

 

damn....i was minutes too late

 

No. It's calling MODDING. And fixing a factory flaw.

I'll never understand why some people are so against the Access Door mod, when it does not lessen the strength of the car & makes a persons life easier. It is fixing a factory oversight & their desire to have the customer bring their car in to be fixed. And I have recently seen a post here on TGO, about how the mechanic did it to their car, after they brought it in to get the fuel pump replaced. Part of my desire to leave mine wide open is because of people claiming it reduces the strength of a car. 5yrs later & mine is still kicking just fine, so so much for making the car weaker.

 

im mainly only against it for the sake of looking for future 3rdgens that havnt had this done. imagine in say maby the next 15-20 years when some guy is the hunt or prowl for a 3rdgen and wants a few things there for him to invest in good resto car, or to make a factory freak car. some are obvious (we still look for these current days) like rust free, accident free, MOD free, ect...so it now seems like cutting a hole there is becoming very common with these cars. so in the future, im guessing "that guy" will know about that common thing when he goes hunting for a 3rdgen,,,meaning when he finds that access hole, it would be a deal breaker. so im not saying its horrible to do or makes it weak...just sayin its gonna be something that a future guy may NOT want happend to a car that he may have very picky and particular plans with. and honestly, doing all that work would turn out to more work than just droppin the damn tank. it only takes aprox 2 hours

 

well that is a good way your buddy did im looking more to 8-9psi which is what my mechanical pump creates and as for future looking im going to do a access door with a lock so its not just a gaping hole https://www.thirdgen.org/forums/imag...es/burnout.gif

 

Well I'm definitely making a fuel access panel this week. Why ?

Because I dropped the tank, replaced the fuel pump, and still no power, I even ran power straight to the wires. So obviously I plugged in the wire adapter or something wrong inside the fuel tank.

And what did I OF COURSE forget to do before I put the tank back in, which was real tough since my exhaust isn't placed exactly how it's supposed to be, I didn't test the pump/tank outside of the car.