For the last 3 years I have ran a AFB on a 1970 Ford 302 since it had a front pcv port to work with the valve covers with the pcv on the drivers side instead of on the pass side,well I finally came up with a 1 inch carb spacer with a pcv port and installed the almost new Holley I had jetted for this motor and noticed it ran much better then I remembered with this carb,the right off idle performance seems to be much better and seems like the motor has more power so can a carb spacer do that or is it my imagination. The reason the Holley was pulled is when I changed the pcv from the pass side to the driver side the extra long hose to the pcv leaned out the Holley so on went the AFB until I found a spacer which ended up taking 3 years and now need to put a pump diaphram on the Holley.
I think I am going to add one to another motor and see what happens,that 302 is in a full size galaxie and it seems to have more power then it ever did.
As "mad" says...yes and no. What a spacer does...beside raise the carburetor, is to add cubic inches/volume to the plenum. This can help, this can hurt, just depends on your combination. 1. It has the effect of slowing the incoming signal to the venturi's and booster venturi's. Makes the engine "think" it has a larger carburetor than it really does. 2. It allows the incoming fuel/air to make the turn to go from the plenum to the runner smoother/easier at higher rpms/butterfly openings. Good thing on most accounts. 3. Adds volume to the plenum. Makes the engine "think" it has a larger carburetor than it really does. Both the open and the four hole spacers do the above things. Obviously...the open spacer does it much more radically/obviously. Then there is the "blended" four hole. This "porting, or blending" to the spacer base helps smooth the air/fuel transition as it leaves the spacer to that there are less places of no flow/low flow as there is with flat, unblended spacers. Same thing as with the open vs., the four hole...the thicker the spacer, the more the above things are exaggerated. All this is to say...the ONLY way of knowing if a spacer will help YOUR engine...is to try them. The quickest way to learn this is to get some chassis dyno time. The other way is to take VERY good notes on car "feel", gas mileage, etc. The dyno time is money well spent. Note also, that you aslo need to be monitoring your spark plugs very carefully...a jet change "could" be of benefit. Mike
Yes, especially if you make your own outta heavily-varnished wood. Mine are 1-1/2" thick, used with an old AFB and a 1406 mainly to keep them cool. Ask me why they're 1-1/2" thick. 8^) And yes, they marginally help mileage but feel better too. Jack E/NJ
The motor has responded positively on the addition to the spacer and will be watching the plugs and will drive it some today,its been a few years since the carb was on the motor and definately forgot how it ran with that carb but it seems much better now and much more responsive.
I personally think your biggest gain was the carb swap. I also am a believer in spacers. I especially like them to keep heat transfer down.
When i had my mill on the engine dyno-my machinist told me anything over 12-15hp from a spacer would be a "home run". I paid for the dyno time, so they let me try all their spacers. I went no spacer, 1" 4 hole, 1" open, 2" 4 hole, 2" open, 1" SuperSucker (tapered 4 into open" stacked with a 1" open- all showed progressive increases up to 15hp. Then i tried just the 1" SuperSucker by itself and it kept the same 15 hp that it gained with the SuperSucker + 1" open hole. What we came to determine was that the Supersucker was allowing the mixture to slow it's turn into the runners and keep the air from flinging out the fuel as it turned the corners. On my original car, i couldn't fit a spacer, but now that the mill is going in the Falcon gasser, I will buy a SuperSucker ( or make my own) since it was a proven help for my combination. You just have to see what works best for your combo. -rick
Now if I could just get the 351-W I have in my 55 sunliner to be just as responsive I would be happy,both cars are heavy and have the same gears but the 55 is a automatic where the custom 500 that has the 302 is a 3 speed. Do not know if it was just the carb or the spacer or both but it runs like I changed the cam and has more power down low where I wanted the power in the 55 so next spring I will tear into the 55 and get it to run like the 302,the 302 is just a stock 70 2 bbl motor with a performer intake and 600 Holley along with a duraspark ignition and truck shorty headers and full dual exhaust plus a dual snorkel air cleaner. Its running good enough that I am done and not going to change a thing.
Now that its running better I think it will get me motivated to stick the 4 speed in it,as for getting the 351 in my 55 to run better it might be a little harder since its a mid 80s motor with less compression and junkier heads and the wrong cam plus a restrictive stock truck 4 bbl intake.
When making changes for improvement...it helps in evaluating the changes when they are made one at a time.......two or more changes and it's difficult to know for sure what worked and how much. Ray
When it comes time to work on the 351 I will have to make more changes then one since the motor is will be apart and I want to save time and money,I want to do a cam and intake change and possibly a head change at the same time but the external changes could be done one at a time. Next change for the custom 500 is slightly quieter mufflers since I now like to open it up and do not want to attract too much attention from the police.
have used the 1" aluminum 4 hole square bore with swirl markings in holes from Trans-Dapt, I think #2431, on small Chevy 327 and Ford 302 with positive results with helping the bottom end performance.
I'm a believer,I have also noticed that a spacer has helped solve the problem I was having with the evaporation of fuel in the carburetor due to the ethanol in the gasoline. HRP
I do not have the fuel evaporation problem on my 55 that also has a spacer,it has a mid 80s 351-W that I would like to get to run like a late 60s or early 70s motor which will be another project this spring. Thinking about adding a spacer to the 460 in my F100 since it has a hot start issue but did install a insulator plate under the carb that I picked up at the Turkey run.
"I have also noticed that a spacer has helped solve the problem I was having with the evaporation of fuel in the carburetor due to the ethanol in the gasoline" I'm not doubting your observation, but I find that very interesting. How would a spacer curb fuel evaporation, which occurs, I'd****ume, when the engine is not running ? Anybody have an explanation why that would happen ?
The problem I was having with evaporation with the fuel in the carburetor was more prevalent during the summer. Usually after driving the car any extended period and parking the car in the shop when the engine was hot is when this took place. The next time I got in the car I had to pump the gas a lot to crank the car. I changed the fuel pump,no change,a new carburetor,no change,new filter,no change,I installed a phenolic carburetor spacer recommended by a fellow Hamber and lo and behold my problems was solved. The car can be hot as a fire cracker when parked and the next day when it's as cold as a cucumber will fire up with the touch of the gas pedal. HRP
The wood or phenolic spacers (probably not the metal ones) insulate the carb from engine heat after the engine is shut off. The fuel is not boiled/evaporated from the fuel bowls, and your car starts like it should the next morning.
Spacers have long been used by racers to fine tune their induction. The question has a simple answer yes it can. In execution it is an entirely different story. "Can" being the operative word. Example, I have a small block that dyno'd a little over 400 hp with a spacer and a little over 375 without it. That was with a modified stock aluminum truck intake and a 3/4" open spacer. Would putting a 3/4" open spacer on your engine give you the same results, probably not unless your engine is built the same way that mine is. it may even take away from your performance. There is an art to tuning and it has nothing to do with what an ad says or even what my results are by changing a specific part. But back to my original answer slightly modified, yes they can but maybe they won't.
Spacers are a trial and error deal. Keep going taller until it wont fit under the hood. I never seem to have the room under the hood. But again I like a nasty cammed up hi comp engine too. I think the biggest difference is the Holly. Its just 1000 times better of a performance carb.
Thanks, HRP. I hadn't considered the engine being hot when parked after a run and the heat transmitting to the carb bowl and boiling out the Ethanol, which makes the problem even worse. The spacer acts as an insulator and helps prevent or lessen the problem. I guess I just didn't have my thinking cap on when I asked, the I appreciate you taking the time to clarify it - makes perfect sense!
A friend uses a 4 inch spacer on a small block Ford. It looks pretty goofy, like a big aluminum rubix cube but he ET's better with it. Calls it his redneck tunnel ram.. Posted using the Full Custom H.A.M.B. App!
I know the wood and plastic spacers help a bunch with the heat but the metal or aluminum spacer on my 55 sunliner does a decent job of keeping the heat from the carb,on my trip to Florida last week I drove it hard and it would start right up after gassing and piss breaks sitting for about 15 minutes unlike the 460 in my F100 that does not have a spacer that is hard to start in similar situations. I picked up a 40 dollar heat shield for it and have not driven it enough to know if I wasted my money.
I had to use a spacer with a pcv port,when I installed the mid 80s factory aluminum valve covers and dual snorkel air cleaner I also used the crank case breather too so I had to move the pcv to the drivers side and the longer hose leaned the carb out. I know it would have been easier just to rejet but I wanted to get rid of the longer hose.
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