Slant 6 gets Holley Sniper

[Henry W]

Here is one recent post I made on another forum on the date of 2/16/2023 about my 1989 F150 with 4.9/300 inline six. I've been working on this truck since 2021.

This is one of the reasons why I've have not been on this forum as much as I wanted.

Project Update:

Lots has happened in over a year.

The Sniper is off, and a Holley 390 is on.

The reason for changing to a carb setup is:
I wanted a fuel system that I can be in control when it needs to be repaired or serviced. Since this truck is my everyday driver, it needs to be reliable. And, I feel comfortable with a carb setup knowing that I can keep parts on hand in case it needs to be repaired.

Before I start going into detail about the project, I would like to thank everyone that helped with this project. Without the guidance, patience and support, the project would have been abandoned or wouldn't have came out to what it is today. I can't express enough thanks.

To the good news,
The truck is running very well. It starts right up and runs smoothly. All the bad stuff that I've been dealing with are gone. The engine ran strong on a very rare test. Its power is felt from Idle up to 4000 rpm. (Rev limiter was temporarily set to 4000 and was brought down to 3500 after the test) After 3500 the engine could use a cam but it went up to 4000 with no problem. There are no flat spots that I can pick up at any rpm range when driving it. The power is so good that It doesn't drive like the same truck, and I constantly have to watch my speed when driving.

The reworked Holley 390 carb, Water heated Offenhauser C manifold, reworked Duraspark II distributor and MSD6AL ignition box are a very good match for the stock EFI engine.

Now to the great news!
I just took it out for a 200 mile trip. Speeds were mostly 55 to 65 mph. Two times I got on it to merge on to the interstate. And once I got on it to pass a loaded semi going up a grade. The MPG recorded was 19.6. If I did not get on it, and drove at a constant 55 or lower, MPG would have been in the low 20's.

The fuel used was 93 octane. From the same gas station, and same pump.

I am very pleased with the project. And I think it's good enough to leave it alone.

The only thing I'm thinking about is, another cam that reduces the DCR so lower grade gas can be used. But this can wait until summer.




Here is some Information:

• 1989 Ford 4.9/300 in-line six engine with high swirl (Fast Burn) head.

• Initial timing is set to 10 degrees BTDC.

• Zero mechanical advance up to 1200 rpm.

• 19 degrees total mechanical advance @ 2850 rpm.

• Vacuum Advance
For Towing: 12 degrees total. Starts at 5 inHg. Ends at 10 inHg. (Ported Vacuum.

For Normal Driving: 12 degrees total. Starts at 4 inHg. Ends at 9 inHg. (Ported Vacuum)


Spark Plugs:
Motorcraft Copper Core BSF44CA
Gap (In.) 0.044


Carburetor:
Holley 390 #0-8007

SPECS:
Primary Main Jet Holley #122-55 (#54)
Primary Power Valve 6.5
Primary Pump Nozzle Size 25
Accelerator Pump Cam color Orange
Secondary Spring Purple


Quick Fuel Secondary Metering Plate # 34-2QFT

SPECS:
.0292" idle feed restriction (Drill brass set screw to .0292")
Secondary Jet Holley #122-64 (#64)


Carb Spacer:
1" aluminum 4 hole 1.450 diameter holes


Intake Manifold:
Offenhauser C intake manifold with Coolent heating block:


Pressure Regulator:
Holley #12-881
Fuel Pressure 5 psi.


Engine Thermostat 195 degrees F.


Note: Stock low pressure in tank fuel pump works well. No need for a larger pump. The fuel lines are all Stock OEM up to where the high pressure fuel pump was. This is where rubber high pressure feed and return fuel line was used up to and from the Pressure Regulator.


She is not pretty but she's a keeper

[Henry W]

Here is another post on 2/18/2023:

"Just completed roughly a 120 mile drive this morning on back roads doing 45 mph to 55 mph. The truck averaged 20.3 mpg."

Anyone that brings up a comment that carb'd vehicles cannot get good fuel mileage need to do some more reading.

Everything has to be properly matched and tuned together.  You just can't buy a carb and distributor and throw it on and expect them to work well. Chances are, it won't.

Since the final tuning, the truck has been left alone and just driven. Life has got simpler.

[Henry W]

Who said in-line sixer's can't have fun.
He is a retired Ford engineer. This guy helped me out a lot with my project.

https://m.youtube.com/watch?v=lG6tOzJHOdw&list=UUXyV0oRA3mc0uTmPPWYW5QQ&index=16

[Henry W]

This Thursday or Friday I will be doing a 1/4 mile run with the Truck.

Will post 0 to 60 and 1/4 mile time.

Truck specs:
• 1989 Ford F150, long bed.
• GVWR 5450 lbs. But truck will be empty, and with a full tank of fuel.
• Carb'd 4.9/300 six.
• 5 speed
• 3.08 rear
• 2wd
• Rev limiter will be set to 4000 rpm.

Any guesses what the in-line six truck will do?

[Tom Reed]

Talk about making a silk purse out of a sow's ear. I always admire a person who races something out of the box. I built a Spit6 back in the day. Triumph used the 4 banger trans behind the 6 and they did not hold up. I made a custom bell housing and put a Toyota 5 speed behind it. Nice combination with the dual side draft Stromburg carbs and 6 into 1 headers.

[Henry W]

Just heard from my mentor. Rev limiter will be set to 4600 rpm. This is the shift rpm for the first two gears.

[mobile_bob]

my bet?

1/4 mile,  18.99 sec @ 79.3mph

are you going to bleach the tires?



bob g

edit: make that 73.9 mph

[Henry W]

LOL, No Bleach!

[Henry W]

my bet?

1/4 mile,  18.99 sec @ 79.3mph

are you going to bleach the tires?



bob g

edit: make that 73.9 mph

In the first (only) test run a couple days ago to test the app. I beat that time not even trying.

[Tom Reed]

are you going to bleach the tires?

Those wide whites make'er go faster when bleached nice and clean. ;-)

[Henry W]

Having second thoughts of winding the engine so high. Will be keeping the rev limiter at 4000. That will be enough abuse.

[DKMC]

You could always step down to an I4....340hp...for starters.

https://www.motortrend.com/how-to/blueprint-engines-four-cylinder-crate-engine-ls-head/?sm_id=paid:sm_id:fb:mtoo:23:OOtraffic:article:m18-65us:mt

I guess with a turbo it would be at least 450, maybe 500hp.
You can even run a Winsor head if you don't like the LS.

[Henry W]

Did two runs at same location marker. The road was in very good shape. Weather was perfect. 75 F. Very low humidity.

The first run, I nailed it. There was no wheel spin. Shifted around 4200 to 4300 in 1st and second, shifted in 3rd and 4th around 3500. There was not much that I could do better. The torque tilted the truck to one side during take off. The engine pulled very well. It surprised me how well it did. But I just can't believe that the time is right.

1st run:You cannot view this attachment.

It just doesn't make any sense. I know the truck is not putting out enough HP to make the ET. It doesn't add up. Unless the engines torque pulled it off.


The second run did not go well. Broke traction and had some wheel hop. Had to back off the throttle to eliminate wheel hop. First and second shifts were about the same as the first run. Shifting to third and fourth is where I messed up . I waited too long to shift. About 4200. Much too high and my ET was slower. It shows that around 3500 is the point to shift.

The time was somewhat a disappointment. But a learning experience. No need to rev the stock engine to the moon.

2nd run:
You cannot view this attachment.

What really doesn't make any sense is my best time had the lowest speed. Please comment what you think.


The truck is officially retired from any more abuse. It's been fun and it's time to use the truck as intended.

[Henry W]

You could always step down to an I4....340hp...for starters.

https://www.motortrend.com/how-to/blueprint-engines-four-cylinder-crate-engine-ls-head/?sm_id=paid:sm_id:fb:mtoo:23:OOtraffic:article:m18-65us:mt

I guess with a turbo it would be at least 450, maybe 500hp.
You can even run a Winsor head if you don't like the LS.

DKMC,
Thanks for posting. Great article. I figured those heads would someday be used on a four cylinder.

There are guys buying those heads, cutting them up and having them welded together to make a head that fits on a ford 300 six.

Yea, I'm an in-line six fan. Perfect engine for my needs. My truck hauls just fine as it is. And I can work on it.