300 Sniper Install and Core Support Replacement

[Tyler]

IT'S ALIVE ! Fired up the truck last night and performed the first ECU grooming tests and operations. The throttle response is outstanding.

Big lessons learned (pictures on page 2 of this thread):

SAFETY FIRST! If drilling/cutting holes in a fuel tank that has had fuel in it, COMPLETELY FILL IT WITH WATER. COMPLETELY. Even a small amount of fuel vapor can ignite and become a scary situation.

Make sure to get all of the metal shavings out of the tank. Dish soap and a lot of sloshing and rinsing with water worked very well.

It helps to have help with fuel tank removal and install (should be empty). Use 2 floor jacks if nobody wants to come over at 8pm on a Tuesday and help you because they have a family, LOL.

The Mr Gasket 4bbl to 2bbl conversion plate comes with capscrews that are too long for the Offy DP intake mounting holes. Go buy 1in normal hex head screws and grade 8 washers and bridge the recess where the capscrews would have gone.

The Sniper may not come with the exact fuel fittings you need or want. Also, it does not come with a fuel pressure gage. I used Amazon to source these loose ends.

Disconnect your starter and fully verify that you have a 12v source in run and crank BEFORE you cut a wire for splicing.

Rollover valve and grommet: check LMC. I didn't and paid way too much for a grommet that didn't work and the company won't post my respectfully dissatisfied review (Fillerneck Supply). $33 for grommet and valve...

Fuel pump block off plate: I bought a beautiful blue anodized aluminum one from broncograveyard. The included bolts were too large in diameter so I got some from Lowes. Looks pretty though...

If converting to the Walker y pipe, and you have an Offy intake do not install the intake manifold until the exhaust pipe is in place. Install order: gasket, FI exhaust manifolds, then the Offy. I found the Walker pipe to go in easiest from the top, not fed upward from underneath thanks to the transmission crossmember for my T18.

I had to buy 2 y pipes because I didn't go with my intuition when the first one seemed bent too far. Consider using a different unit like Bosal. Also I expended 2 hours and 4 grinding bits making one of the holes match the pipe ID for the rear bank. The O2 bung also had to be cleaned up in order for the sensor to screw in. There are pictures on another thread in this forum concerning y pipe install.

I have a double belt 1G alternator. When my lights are on (they are LED) my blinker is very very slow and sometimes fades away when I have the blower running as well. Looks like my next project is the 3G conversion...

Don't forget that the carb 300s have a different gasket than the FI 300s!

The new core support may require you to readjust fenders and hood alignment.

Junk Yards have cool stuff! Especially all those little pieces you can't buy anywhere else.

Have patience and enjoy the process!

Pictures to back up my lessons learned in the above post.

 

[Gary Lewis]

IT'S ALIVE ! Fired up the truck last night and performed the first ECU grooming tests and operations. The throttle response is outstanding.

Big lessons learned (pictures on page 2 of this thread):

SAFETY FIRST! If drilling/cutting holes in a fuel tank that has had fuel in it, COMPLETELY FILL IT WITH WATER. COMPLETELY. Even a small amount of fuel vapor can ignite and become a scary situation.

Make sure to get all of the metal shavings out of the tank. Dish soap and a lot of sloshing and rinsing with water worked very well.

It helps to have help with fuel tank removal and install (should be empty). Use 2 floor jacks if nobody wants to come over at 8pm on a Tuesday and help you because they have a family, LOL.

The Mr Gasket 4bbl to 2bbl conversion plate comes with capscrews that are too long for the Offy DP intake mounting holes. Go buy 1in normal hex head screws and grade 8 washers and bridge the recess where the capscrews would have gone.

The Sniper may not come with the exact fuel fittings you need or want. Also, it does not come with a fuel pressure gage. I used Amazon to source these loose ends.

Disconnect your starter and fully verify that you have a 12v source in run and crank BEFORE you cut a wire for splicing.

Rollover valve and grommet: check LMC. I didn't and paid way too much for a grommet that didn't work and the company won't post my respectfully dissatisfied review (Fillerneck Supply). $33 for grommet and valve...

Fuel pump block off plate: I bought a beautiful blue anodized aluminum one from broncograveyard. The included bolts were too large in diameter so I got some from Lowes. Looks pretty though...

If converting to the Walker y pipe, and you have an Offy intake do not install the intake manifold until the exhaust pipe is in place. Install order: gasket, FI exhaust manifolds, then the Offy. I found the Walker pipe to go in easiest from the top, not fed upward from underneath thanks to the transmission crossmember for my T18.

I had to buy 2 y pipes because I didn't go with my intuition when the first one seemed bent too far. Consider using a different unit like Bosal. Also I expended 2 hours and 4 grinding bits making one of the holes match the pipe ID for the rear bank. The O2 bung also had to be cleaned up in order for the sensor to screw in. There are pictures on another thread in this forum concerning y pipe install.

I have a double belt 1G alternator. When my lights are on (they are LED) my blinker is very very slow and sometimes fades away when I have the blower running as well. Looks like my next project is the 3G conversion...

Don't forget that the carb 300s have a different gasket than the FI 300s!

The new core support may require you to readjust fenders and hood alignment.

Junk Yards have cool stuff! Especially all those little pieces you can't buy anywhere else.

Have patience and enjoy the process!

Congrat's!!!!! That's just a good feeling.

And thanks for the lessons-learned list. It'll help someone.

Looking forward to your thoughts after driving it a bit.

[ArdWrknTrk]

Pictures to back up my lessons learned in the above post.

Glad to hear it's all come together for you!

So the Y-pipe does fit (from the top) or the old one was bent and the new one is good?

We used a 1 7/8" hole saw on a hex extension and had that rear pipe cleaned out in a minute or two.

Sorry you had so much grief.

[grumpin]

Glad to hear it's all come together for you!

So the Y-pipe does fit (from the top) or the old one was bent and the new one is good?

We used a 1 7/8" hole saw on a hex extension and had that rear pipe cleaned out in a minute or two.

Sorry you had so much grief.

Nice job!

[Tyler]

Nice job!

Thanks! And thanks for the help. It's much easier to undertake these types of projects when you have a community that is eager to provide encouragement and guidance. Even if you could have figured it out yourself. "Jump, jump, jump, jump....don't land on that rock!" LOL.

 

[ArdWrknTrk]

Thanks! And thanks for the help. It's much easier to undertake these types of projects when you have a community that is eager to provide encouragement and guidance. Even if you could have figured it out yourself. "Jump, jump, jump, jump....don't land on that rock!" LOL.

Can you elaborate on what happened when drilling your tank?

Back in the day, when brazing motorcycle tanks, we would put a chunk of dry ice in there.

Fast forward and I use the gas from my Mig welder to purge because I can't really weld a new bung or petcock in under water.

It just boils and pulls all the heat away.

[Gary Lewis]

Can you elaborate on what happened when drilling your tank?

Back in the day, when brazing motorcycle tanks, we would put a chunk of dry ice in there.

Fast forward and I use the gas from my Mig welder to purge because I can't really weld a new bung or petcock in under water.

It just boils and pulls all the heat away.

Ty - Much easier when you have a community to ask questions of.

Jim - I would never have thought of using the gas from the MIG welder! Good thinking!

[Tyler]

Can you elaborate on what happened when drilling your tank?

Back in the day, when brazing motorcycle tanks, we would put a chunk of dry ice in there.

Fast forward and I use the gas from my Mig welder to purge because I can't really weld a new bung or petcock in under water.

It just boils and pulls all the heat away.

The best thing that happened is that nothing happened. I filled the tank completely with water before drilling the hole. Used some 30W oil as cutting oil to avoid sparks. Then cleaned it all out using dish soap and sloshing.

[Tyler]

Ty - Much easier when you have a community to ask questions of.

Jim - I would never have thought of using the gas from the MIG welder! Good thinking!

Yes, Gary. Indeed! And thank you, my friend.

I took my first real drive yesterday after the taillight fiasco was cleared up. My local shop installed a 2.5" cat back exhaust behind the walker y pipe and cat. It sounds fantastic except for a decent drone on the highway. I'm having a resonator added.

However! I cannot overstate how fantastic the truck runs with the Sniper. Now I understand why everyone loves this motor. (And also how badly mine was tuned with the 4 barrel carb on it.) Night and day difference. The throttle response is instant.

No regrets, just miles of smiles. And I don't have to worry so much about ethanol in the fuel or altitude changes.

A friend of mine owns a dyno and wants to see where the power band is as well as the numbers to compare with Ford published specs. If we run it, I'll post results here.

[Gary Lewis]

Ty - Much easier when you have a community to ask questions of.

Jim - I would never have thought of using the gas from the MIG welder! Good thinking!

Yes, Gary. Indeed! And thank you, my friend.

I took my first real drive yesterday after the taillight fiasco was cleared up. My local shop installed a 2.5" cat back exhaust behind the walker y pipe and cat. It sounds fantastic except for a decent drone on the highway. I'm having a resonator added.

However! I cannot overstate how fantastic the truck runs with the Sniper. Now I understand why everyone loves this motor. (And also how badly mine was tuned with the 4 barrel carb on it.) Night and day difference. The throttle response is instant.

No regrets, just miles of smiles. And I don't have to worry so much about ethanol in the fuel or altitude changes.

A friend of mine owns a dyno and wants to see where the power band is as well as the numbers to compare with Ford published specs. If we run it, I'll post results here.

So glad it runs well. That makes it all worthwhile.

As for the engine spec's, we have them on the page at Documentation/Engines/300 Six and then the Specifications tab. But you have to scroll down as they didn't put the torque and HP spec's in the dealer facts books until 1982.

On the drone, you might let the system take a "set" before adding a resonator. I have ~1000 miles on my system and it changed quite a bit during that time. But most of what happened was that the drone became more focused, right at 65 MPH in OD.

So I understand your desire for a resonator. But what one to use might differ with what it settles into.