Spacing question

[TINBENDER59]

rails are one of the easiest things to make, you should just diy.

lt1 stock rails are really shitty slip fit oring things. they aren't stable at all unless bolted solid to an lt1 intake.

also it's more optimal to feed both rails in parallel, lt1 has series feed rails.

I wouldnt run a fuel rail that wasnt bolted down???? so I don't understand that statement?? and at 45psi, Parallel, or series aint gonna make diddly difference. Unless, of corse, you are unleashing 1000hp at 9K+ at which point it would be a little bit different fuel delivery process IMO??? But you can rework the LT1 and TPI rails to be parallel fuel delivery with rubber fuel lines with AN fittings, My next project will be thus,

[EagleMark]

For a cheap MPFI the LT1 intake can be converted to a distributor? And if you PM Lextech he has one for sale with all the work done. IIRC it does not have injectors but the intake work needed was done...

[1project2many]

Cheap and easy to convert LT1 to distributor??? Having looked at this project years ago, I never thought a "good" conversion was cheap or easy.

Why would high rpm and high horsepower make a difference in series vs parallel plumbing? It's about line size, rail size, pump flow, injector flow volumes, etc. Running in parallel reduces number of restrictions and reduces pressure waves transmitted through system. Crossfire injection system was an extreme example. OE manifolds used larger injector on when TB's plumbed in series. Changing to parallel allows equal size injectors without mismatched fueling. That engine produced what... 205 hp at maybe 4500?

TINBENDER59, along with injector spacing, be sure to measure the angle of the holes in the fuel rail (if any). The Gods of Fire and Destruction love it when injectors are installed in fuel rails at an angle that prevents best O ring sealing.

Steveo, any advice on how to DIY a set of rails with relatively basic tool for non-machinists? Seems like consistently measuring compound angles would be a bit tricky when setting up a rail in a drill press. Same for boring the manifold. Not sure I agree with "really shitty fit" O'ring comment. 'I've been doing this since the days when GM trainers freaked out if you didn't treat every O ring with kit gloves. I can count on one hand, maybe, the number of problems I've seen with properly installed rings in properly machined holes.

405 cubes, sometimes the best intake available to us as street guys is the one that does the least damage. Putting a GM TPI intake on a large cube engine would make stupid huge amounts of torque... until 3500 rpm or so. An old F.I.R.S.T. TPI would do much better but most people don't want to spend the money to buy one. So you have to pick from what's left over. Intake manufacturers will list an intake's operating range based on a range of engine displacements and list those numbers as a guide. Because an intake is listed from 2500-7000 rpm does not mean it will make best power on your engine at 7000. It only implies the intake will not be happiest with a low end cam, tall rear gears, and a tight converter.

For viewing pleasure, the F.I.R.S.T. system installed:

[405cubes]

Good points, and agreed.
-even a stock rail has 400hp capability. Why waste budget on high$$$ kits....
Think tpi &lt1 share spacing, but different angle.

-re the intake-used 7101's are 50-100$ and with 1500-6500 rpm range on a 350, with my increased displacement it brings it to around 1300-5400 rpm. Seems very ideal :)

Re:tpi- seems it would choke me out sooner, and given the 400's cooling system requirements ...the whole distributor hole deal...When an off the shelf edelbrock has it dead located...currently im a little uneasy with that route.


Fwiw factory flex fuel injectors offer good lb/hr numbers-probably what i will use.

Cheap and easy to convert LT1 to distributor??? Having looked at this project years ago, I never thought a "good" conversion was cheap or easy.

Why would high rpm and high horsepower make a difference in series vs parallel plumbing? It's about line size, rail size, pump flow, injector flow volumes, etc. Running in parallel reduces number of restrictions and reduces pressure waves transmitted through system. Crossfire injection system was an extreme example. OE manifolds used larger injector on when TB's plumbed in series. Changing to parallel allows equal size injectors without mismatched fueling. That engine produced what... 205 hp at maybe 4500?

TINBENDER59, along with injector spacing, be sure to measure the angle of the holes in the fuel rail (if any). The Gods of Fire and Destruction love it when injectors are installed in fuel rails at an angle that prevents best O ring sealing.

Steveo, any advice on how to DIY a set of rails with relatively basic tool for non-machinists? Seems like consistently measuring compound angles would be a bit tricky when setting up a rail in a drill press. Same for boring the manifold. Not sure I agree with "really shitty fit" O'ring comment. 'I've been doing this since the days when GM trainers freaked out if you didn't treat every O ring with kit gloves. I can count on one hand, maybe, the number of problems I've seen with properly installed rings in properly machined holes.

405 cubes, sometimes the best intake available to us as street guys is the one that does the least damage. Putting a GM TPI intake on a large cube engine would make stupid huge amounts of torque... until 3500 rpm or so. An old F.I.R.S.T. TPI would do much better but most people don't want to spend the money to buy one. So you have to pick from what's left over. Intake manufacturers will list an intake's operating range based on a range of engine displacements and list those numbers as a guide. Because an intake is listed from 2500-7000 rpm does not mean it will make best power on your engine at 7000. It only implies the intake will not be happiest with a low end cam, tall rear gears, and a tight converter.

For viewing pleasure, the F.I.R.S.T. system installed:

[EagleMark]

Steveo, any advice on how to DIY a set of rails with relatively basic tool for non-machinists?

There is a guy who did a write up for everyone to follow on how to drill an intake with a hand drill the injector holes that had a bubble site on it? No I won't link it!

[1project2many]

Haha...

The tech is so much better in that site.

[405cubes]

As far as simple tools-only rails, id go square tube mild steel.
If round had to be used you can clamp or temporarily tack weld the ends TO a square piece, so that you facilitate consistency of angle from piece to piece.

Drilling can be fun on round-use a high speed and very little force, until hole is to drill diameter. Then push.
Die grinding little flat spots can help.

I did see a blasphemy of machining rails elsewhere.. And to clear up some myths-dont pre drill with smaller sizes and step through several sizes to get there. The POINT of the drill guides it, not the sides. You might run a 1/8 bit on your punch mark, but dont drill through!
Rule of thumb. Punch, pilot, drill. Rant over.

Not that ive done it before on fuel rails, just done a bazillion things similar. Lol just had a guy with an artificial hand come in and we revised some stuff on his hand. I love my job!

Huge question-referring to rust inhibitor. Nickel or tin plating? Immunol? Seems fuel wouldnt erode either one.
Lol, i have several home-made tools i coated with dykem and its still on after years of use, submerging in thinner, and all other kinds of misuse and abuse. Is it worth nickel plating them?