Hi all,

So, I finally got my engine installed into my new Bronco. Last year, just a few months after finishing my install of the high performance engine I'd had built, my '81 Bronco was rear ended and totaled. I bought it back and stripped it down to the metal, taking all my upgrades, engine, transmission, etc. out of it.

As a replacement, I found a really nice 1985 Eddie Bauer Bronco with a 302 and an AOD in it. It took a while, but I finally found the time to pull the 302 out and swap in my engine into the '85.
I had plans to put my NP-435 in it as well, but decided to go with a freshly rebuilt ZF5 speed.

To top it all off, I decided I'm done with carburetors. They're fun to tinker with, and I enjoyed learning them and working on them, but for a year round daily driver that I need to get me to work and back in -10° to 110° weather, I got tired of trying to keep them in tune with all the lean hesitations, bogs, etc. that come with it. It was time to try a Holley Sniper EFI!

After asking around, and talking with Holley, I decided on the 2bbl version. It's rated for up to 350hp, which I'm pretty sure my engine isn't putting out. And it's rated at 580cfm, which is plenty.
The 4bbl version is rated at 650hp and is a 800cfm. It would probably work, but that's pretty big. From what I'd been told, using more of the system's range allows for finer control. With the big one, I'd probably only be using about 30% of its range, whereas with the 2bbl version, it'd be something more like 70%.
I also had to go with the black one to fit the color scheme of my engine.
So, the model I went with was the Holley 550-850.

https://www.holley.com/products/fuel.../parts/550-850

Certainly not a cheap investment, but when I figured how much I'd spent on carbs, tuning parts, jets, valves, springs, wideband O2, etc. the cost really wasn't that much different. Over the last few months, I've been selling off all of my carb parts to help pay for it, meanwhile driving the Bronco with the 302 in it.

One perk of the swap is that the 302 in '85 is fuel injected, so I already had a high pressure fuel system in place, complete with the necessary return line, etc. It made my job a lot easier.

First things first, I knew that my long time Offenhauser DP wasn't going to work. I originally posted it up on eBay, but a friend on the forums here contacted me and we swapped straight up. I sent him my DP and he sent me his C. It worked out great!



Once the EFI kit arrived, I test fit it on the intake, along with the 2bbl - 4bbl adapter plate I purchased.







Next, the intake, like the EFI kit, needed to match the engine.









I painted up the 4bbl -> 2bbl adapter as well.



And test fit again.



The EFI kit requires mounting a coolant temperature sensor. I was fortunate in that I had an outlet that had a port in it. This was from my original engine that used the port for a ported vacuum switch, which opened and closed the EGR. It sees a constant coolant flow, and is the right thread pitch, so it was perfect.






Next, I installed a fuel pump block off plate on the engine. This one states that it's "For Chevy V8 and other V8 engines", which I got a laugh out of.



Marked the Remflex gasket with marker so I could get the manifolds lined up just right.













I included a fuel pressure gauge in the setup so I could make sure the stock setup was sufficient enough to supply the necessary 58.5psi.



I wanted to keep the throttle linkage from the 302. I had a Lokar cable on my last setup and didn't like it. The gas pedal is at an angle to the firewall, and the stock setup uses a curved tube to guide the cable. The aftermarket Lokar didn't, so the cable would always cut through it. I had to come up with some clever solutions to make the cable come in straighter and it never worked very well.







Pulled the sleeve off so I could cut it without cutting the cable.



Once properly trimmed, it lined up nicely with the linkage.





I still need to figure out how to hook up the cruise control cable, but that's another project.

Coolant temp sensor in place:



The Sniper EFI uses -6 AN fuel fittings, so I had to come up with a few adapters to tie into the stock nylon fuel lines. There's lots of adapters for 5/16" an 3/8" fuel line, but both of the stock lines on the 302 are 1/4", which is pretty much non-existent in the aftermarket world. Go figure.





Once I had a -6 AN fitting on the fuel lines, I made two hoses and connected the fuel line and the return line.









I'd been nervous for a while that the stock fuel system wasn't sufficient enough to make the necessary pressure. I'd been told the older EFI engines were around 40psi or so, which is 20 shy of the necessary 58.5.
So, I ran a 12v wire to the fuel pump to power it up and pressurize the system. I was pleasantly surprised that it went up to 75psi. Plenty! (The Sniper system has a built in regulator).



Next, the wiring! It looked intimidating at first, but in the end, there were only a few basic connections. Most of them were unused. There were a number of different wires for different ignition setups, and then a few more for electric fans, which I don't have. The last few are ones that I will use in the future and are for A/C kickdown, etc. My A/C system isn't working at the moment and will be a project I tackle next spring, so I'll tackle the wiring for those at that time as well.
In the end, I had to hook up a positive, negative, key on, coil, and fuel pump wire. Really not too bad at all.





There were some fuel pump and system relays/fuses I needed to mount. I found the wires for these to be a hair short, and I couldn't mount them on the fender, so I put them on the wheel well.



As soon as the wiring was in place, I turned the key on. The handheld powered right up.



A couple of different initialization setup options. The engine displacement cracked me up and made me shake my head. WHY does the range go as low as 10 cubic inches? Who's heard of a 10 cubic inch engine? Especially one that someone would be putting an EFI kit onto! And 2000 cubic inches? Nothing like a good ol' 32 liter engine.



The readout has some very handy gauges for more than just the EFI system. Being able to see actual coolant temps, battery voltage, throttle position, fuel flow rate, etc. is really handy on a daily basis.



Now that my wiring is in place, I bundled them all up and put them in the sleeves that Holley provided.









Considering that I was going a full V8 to I6 swap, as well as an automatic AOD to manual ZF5 swap at the same time, my Bronco had been sitting for about a month at this time. I have a full writeup over on FSB if anyone is interested:

https://www.fullsizebronco.com/forum...uer-build.html

Finally time to fire it up!! Since it had been about half a year since the 300 had ran, it was bone dry inside. I spun it up with a drill to build up oil pressure and get it lubricated.
Cranked the key a few times and backfired and popped through the carb. Immediate symptom of having the distributor 180° out. Lined it all back up and, yup, it was now pointed at the #3 post. Restabbed it, and turned the key and VROOM!
It instantly fired right up. However, it was really lean and idling high. I quickly noticed that a vacuum cap had blasted off when it backfired, so I put it back on and the RPMs dropped right down to a nice, smooth 950. I still had to set the throttle position, but that was easy enough.
I watched the engine temp climb on the handheld until it hit 160° and it immediately clicked over into LEARN mode. No fuel leaks and no coolant leaks.



Once it warmed up, I adjusted the throttle until the IAC read between 2 and 10 (as per instructions) and the RPM dropped right down to 750. Everything seems to be working just like it should.
So... time for a drive!

I had gotten used to the soggy performance of the 302 and the AOD over the previous few months, so I hit the gas a little too hard pulling out of the garage. Throttle response was INSTANT and the tires chirped and the Bronco lunged out.
I can't deny it put a huge smile on my face.
Drove it around the block and neighborhood, and it was immediately the best my engine has ever performed. It's everything Holley advertised! There's no hesitations and no bogs. Even the slightest one is gone the next time, because the computer corrects and removes it. I've never had very good throttle before off the line so I've had to retrain myself not to feather the clutch. It just goes!

Now, having had driven it for a week, I am absolutely in love. The high performance 300, coupled with the Holley Sniper EFI and the ZF5 speed is a dream come true.
Even though there are some "advanced" tuning options on the system, I love knowing I don't have to ever tweak and fiddle with it again. It fires right up every morning, and even though it's getting colder outside, it drives the same every day.

I also like that I can set my idle, acceleration, and cruise AFR settings with the touch of a button. I have my idle at 13:1, power at 12.5:1, and cruise at 15.5:1 and it seems just about right.
Yes, it was a bit of an investment, but so far, it's been worth every penny. It's like driving a new car.

 

 

Thanks! I'm sure I glossed over some of the details, but it really was a pretty straight forward install.

No, there's no fuel type input. From what I read, the only time it really becomes an issue is when you go with E85. Apparently, the "hack" is to simply enter in your engine displacement with an increase of about 25 - 30% and then it works perfectly. But, for E10, I don't really think it makes too much of a difference. The energy content difference is only about 3%, which I'm sure it's designed to accommodate for. I haven't noticed any issues with it so far and the AFR looks spot on!

I'll be interested in checking the plugs too. I figured I'd give it a week or two and then have a look-see.

 

Great job, Justin!

 

As is usual for you AB this is a most excellent write-up!

 

Thanks David and Howard!

Honestly, though, I hope it's the last write-up I do for a long time, hah.
I think this is a winner, so that should be the case. It'll be nice to just have it where I want it and enjoy driving it.

 

Justin, you are the man! Mad props to you buddy flawless write up and congrats on the new setup!

 

Thanks!
It's a pleasure to drive every day
I highly recommend it to anyone who can afford it, especially for a daily driver.

 

Congrats bud! looks sharp, and sounds like it performs even better than it looks! here's to many faultless miles...cheers!

 

That's a cool set up. Have you checked the spark plugs since the swap? I'm curious how even all the cylinders are running with the single TBI. A system running two of the TBI's on a dual carb intake would be very cool.

 

I haven't checked them yet. I keep meaning to, but then forget when I get home from work. I'll try to remember to do so tonight.
I would imagine it's pretty similar to the dispersion that a carb does, but who knows?

I agree, a double TBI (albeit expensive!) would be super cool. I think you have to get a special setup though that is designed to work in tandem with another one, or they'd probably keep throwing each other off.

At that point, I'd probably just go with the stock MPFI and retrofit it with a MegaSquirt system or something.

 

5 to 7 lbs of boost w/ MS. that'd be the bees knees. of course, like everything else...it boils down to time & $$$.

 

I know with a single carb on a 240/300 you will always have some lean/rich cylinders. That's where the dual carbs really helps even out the A/F distribution.

What all does your TBI have for sensors in the TBI itself? I would think a TPS, MAP and some kind of IAC and IAT. For dual TBI's you need to somehow sync. up the linkages and just run a TPS on one of the TBI's. Or you would need to move the TPS to some kind of external throttle linkage bellcrank, etc. And you would want to supply the vacuum signal going to the map sensor off some kind of vacuum tree/log. Kind of like what your Bronco would of had on the firewall stock. But the Multiport set up with a aftermarket/custom controller would be a better setup over multiple TBI's. I was thinking something like a stock EFI lower intake with larger injectors a custom plenum box and three 5.0L/5.8L truck throttle bodies would be a cool set up. Kind of give it that down draft Weber carb look. Plus you wouldn't need to pull the upper intake to pull a valve cover. Like a stock EFI requires.

Anyways you've got a cool set up there. Hopefully it gives you many trouble free miles. I'm kind of paranoid about stuff like that. I think if it was me I'd carry a carb and FPR with in a box just in case there was ever any issues while on the road.

 

The Sniper uses a wideband O2 sensor, as well as a TPS, IAC, IAT, MAP, and an CTS.

For reference:

TPS - Throttle Position Sensor
IAC - Idle Air Control
IAT - Intake Air Temperature
MAP - Manifold Air Pressure
CTS - Coolant Temperature Sensor

I agree that I'm a little nervy about it, especially with some of the far out places I go, and have thought about carrying a spare carb with me, as well as a regulator. In my case, I have a 5 - 7 psi in-tank pump and a 40 - 80 psi high pressure pump mounted up by the engine. If something were to go wrong, I can install the carb and disable the front pump. It'd get me home.
Although, I haven't read many issues with them not running. Maybe issues with a sensor going out and them running rich, but they always still run.

Either way, yes, here's to many trouble free years.

 

AB, I'm confused a bit (not unusual for me!), in post #1 where you had all the install pics, there is this comment about the fuel system:

"One perk of the swap is that the 302 in '85 is fuel injected, so I already had a high pressure fuel system in place, complete with the necessary return line, etc".

The quote above seems to contradict that, can you clarify?

I'm interested in this for my '81 F100 2wd, which of course does NOT have a HP fuel system from the factory. I'd need to put an after tank fuel line, and install a return line? Thinking out loud, I wonder - is there an off the shelf tank/pump setup aftermarket that would work?

Regardless, wanted to understand how you did it.

Great DIY thread!