Back in 2022 when I announced that I had purchased a brand new Summit Racing carburetor, I was surprised at the number of our blog subscribers that showed interest. It is hard for me to know the backgrounds and the working experience of well over a thousand of you that visit each month, but we can surmise that a large majority of the visitors to this site would fall into the DIY category of automotive and restoration work. Many of us just like to drive our cars and enjoy them on the streets for a cruise.
At the track or on the street (like my daughter's wedding) the 1955 Ford loved the Holley carb.
Over the past several years, this will be my third carburetor to install on the 292 Y Block V8. While I live in a temporary situation, I cannot but help find a way to turn a few wrenches in the garage. The 312 Y Block build has been delayed somewhat, but most of that is just due to the recent move and the lull over the holidays. For that particular engine, I do plan to have yet another carburetor change as plans are in the works to install a 1957 2x4 Holley 4000 setup that I rebuilt some time ago. You can read more about that beginning at this post: 2x4 Carburetors. As you read those posts (three in total), you will note that I do plan to use electric chokes on the teapots. So, at some point I will need to have my wiring harness set up for just such a venture. The installation of this Summit carburetor will provide a test run since the new unit has an electric choke cap and will need the 12 volt source and wiring. (As you will note later on, I did wire up a 30 amp relay to handle both electric choke caps once I make the switch to the 2x4 manifold.)
The Holley 1850 carburetor has given good service, but will be used on other projects.
By now you may be wondering why I feel a need to switch carburetors once again. After all, the Holley 1850 currently installed operates just fine and proved itself again at the Fast Fords race back in June. From day to day on the street I experience trouble-free service. The urge I have to switch carburetors now concerns the "tunability" of the Summit carburetor versus the Holley. It may come as no surprise that this new carburetor actually carries quite a few Holley parts - from butterfly linkage, secondary vacuum controls, even down to the jets. Maybe a better way to explain would be to say that the Summit carburetor will be easier to tune and make adjustments on the go. While the videos show more of the comparison, the greatest difference in my opinion is the fuel bowl design. Holley's have both a primary and secondary fuel bowl that are secured to the "throttle body" of the carb with four screws. Of course, many of us have dealt with the metering blocks, having to get a new gasket each time you change out jets or a power valve, and all the rest. Not so with the Summit unit - the lid removes to expose both bowls. There are other improvements as well - the floats are center hung and both bowls have sight glasses.
The old Holley 1850 was removed and the intake surface cleaned.
The intake was taped off since new studs had to be installed and small hardware was about...
The box included a plethora of small items to help install the carburetor.
The carburetor came shipped with a variety of extras. In the box, Summit included a dual feed fuel line, a thick mounting gasket/spacer, a gasket for the air cleaner, an air cleaner stud, various linkage parts and fitting hardware, and even a small length of wire for the electric choke.
There were a nice set of printed instructions in the box as well.
The only let down we experienced was that the dual feed fuel was indeed bent. More of this discovery and some of my concern after installation (potential leak?) are shown in the video. I guess what had taken place was that the fuel line was set in the box at an odd angle. It wasn't too difficult to bend things back to square, but the chrome did chip off at the joint leading to the primary fuel bowl.
The fuel line was bent right out of the box...
Speaking of fuel line, the old 5/16" fuel line from FoMoCo reared its ugly head in that I had to purchase an adapter. (Mid-50's Fords were 5/16" fuel line from tank to carb, but a large majority of the carburetors, fuel pumps, and other fuel related items we deal with today are 3/8".) The fuel inlet supplied by Summit is a female flare of 3/8" size, and the parts bag did have a fitting but the other end was the barb style. Since I wanted a clean look with no rubber hose (except for the fuel filter and pressure gauge more near the fuel pump) I decided I would have to find an adapter that would be 3/8" male flare and 5/16" female flare. I made the mistake of wasting my time by visiting three auto parts stores in town - they had very few fittings in regular inventory. Jumping online when I arrived back at the garage, I pulled the trigger on an eBay listing for just the adapter I needed. It arrived within 4 days and fit perfectly.
An adapter fitting had to be ordered to mate the 5/16" and 3/8" sizes.
Two other small nuances of fitting the new carburetor were the lengths of the linkage rod and the air cleaner stud. I had enough parts and hardware in inventory to take care of those issues.
The switch to the Summit carburetor meant a longer air cleaner stud and linkage rod.
The part of the installation that required the most work was to wire the electric choke. All of the other carburetors ever installed on this car utilized a manual choke so no wiring harness existed. I did not use the wire supplied by Summit but went straight to my electrical cart to build my own harness and wire a relay. Several years back I decided to place all of my wiring tools, wire stocks of several gauges and colors, terminals, shrink wrap, light sockets, switches, relays, and all associated hardware into a rolling tool cabinet that has shelving and several drawers. The organization and accessibility have been a great help. I wired up the relay direct to battery power on a separate stud near the starter relay and ran the trigger lead to the coil. The installation video shows my test runs with a multimeter, but suffice to say everything went very well. While most electric chokes do not require relays I am certainly an advocate of their use. A 20 amp fuse was wired ahead of the relay power from the battery. Of course, I anticipate the possibility of wiring two chokes when the 2x4 manifold is installed once the 312 build is finished.
The electric choke required a hot lead from a 12 volt power source triggered by the ignition.
The relay for the electric choke was placed next to the starter relay.
New, hard fuel line was bent and the PCV and vacuum advance lines were connected. Before filling the fuel bowls to test the lines for leaks, I did double check the full movement of the butterflies by hopping in the car and depressing the accelerator pedal a few times. For work like this, I am ever so thankful that I installed an inline, electric fuel pump several years back. Filling the bowls and testing for leaks was just as easy as flipping a switch under the dash. In the video you can hear the fuel fill the lines and enter the fuel bowls. After watching the fuel pressure gauge needle rise and level out to indicate that the float needle had seated, I turned off the switch and checked all of the connections for leaks. All good! Since it was now dark I closed the hood and waited for a good day to run the new carburetor and tune it to the 292 and my driving habits. But, foul winter weather came so the Summit carb had to wait until after my return from holiday travel to show us its potential.
Summit 500 cfm Carburetor Installation Video
Firing up the Carburetor
Most of the delay in this post is due to weather and travel for church ministry. It has been right at one month since I made my last blog entry! Just this past weekend I was back in town with time and weather on my side. I popped the hood on the old Ford, double-checked my new fuel line, and ensured that my electrical connections were in order. Turning the key, the engine IMMEDIATELY fired and ran. However, the idle was way too high. It leveled out at 2500 rpm or so and then slowly started climbing... I shut it down.
What made the idle rpm spike? I had not made any adjustments from factory settings.
Since I had installed the carburetor out of the box and not touched any of Summit's original settings, I assumed the issue had to be the new choke. So, I broke out the instructions and referenced the page that explained the choke adjustments. Sure enough, one of the first warnings stated was that if the fast idle on the choke seemed too high, "SHUT OFF THE ENGINE!" Summit declared. Thinking that was the problem, I referenced the diagram.
The fast idle set screw is quite small and hard to locate.
With a 1/4" open end wrench I turned the screw head to decrease the set length and fired up the Y Block. Nope, no change. I adjusted it again, and still the idle was way too high. Desiring to rule out the choke mechanism entirely, I loosened the choke cap and spun it until the choke was completely open. I hit the key and again experienced no change. Now I was really scratching my head. The float bowl levels looked good, I had not fooled with any of the carbs adjustment screws, so what could this be?
Next up was to unhook the vacuum advance and plug the port on the carburetor. When I started the engine this time, the rpm lowered by at least 1000. "Bingo!" I thought. And, sure enough when I checked the distributor it was not tight and relatively easy to turn.
This photo was snapped while trying to time initial advance.
I grabbed a timing light, hooked up the leads, and went to work. Before too long, I discovered that the curb idle screw was adjusted way too far in its travel. Incrementally advancing the distributor's timing forced me to turn down the set screw at the primary butterflies. I leveled off at 10 degrees before TDC with the vacuum advance unplugged. She rumbled nicely in that slight lope the E4 camshaft has at about 675 rpm or so, and I got everything ready for a test drive. The video below tells more of the story and my satisfaction with the results.
Summit 500 cfm Carburetor Installation Video Part 2
Getting in the garage is certainly rewarding, but I must admit most sessions in the shop end up taking me to school. In this instance, I made mistakes on two counts: 1. Trusting Summit's information concerning factory settings and 2. Not ensuring that my distributor clamp was properly torqued. In the end, it all turned out pretty good. As we motor along I do plan to give updates, and will hopefully have time really soon to tackle that noisy speedometer cable. (You can hear it in the video - it is the original and I have lubed it a few times but it is just wore out.)
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Thanks!
The Hot Rod Reverend
aka Daniel Jessup