I recently finished up my bronco build and put larger tires on it i am having horrible power with my engine its a stock 302 with 40,000 on it and has always ran fine i found an aftermarket holley carb that will fit it and I am wandering if it might help. Also i just put 32 inch tires on and I'm not sure if it is to supposed to be sluggier or not. It just acts like theres not power and flooding.
Power Trouble
- Thread starter 73 horse
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BroncoJoe19
Active member
A '71 302 has about 210 hp. Sluggish can only be determined by what you are comparing it to. IF you put larger tires on it, it will be more sluggish, if you compare it to itself.
I am kinda new to this, and may not be familiar with the terminoligy that you are using. I don't know what "just finished up with my Bronco Build" means. DId you rebuild the engine, or other major parts? You said "my engine its a stock 302 with 40,000 on it and has always ran fine" did you make any changes to it that made it run-- un-fine? I am not sure if you are having a problem, or if you wanted to put on larger tires, and now need more horse power to drive those tires.
You mentioned that you found an after market Holley Carb. They are excellent manufacturers, and although I don't know one carb from another, no one else will be able to answer that question unless you let them know what carb you have and which one you are thinking about putting on.
I hope that you understand. The more information that you give to us, the more we will be able to help you.
Talk with you soon
joe
To start out with, if you had original size tires (P235x75r15 - roughly 27x8) on it and you went to a 32x10.5, then yes, you are going to see a substantial "power loss". It would be like you running in a pair of shoe that fit compared to a pair that are 2 sizes too big, you can do it but you don't get the same results. The only way, excepting an engine rebuild, you are going to get that loss of power back is to regear or go back to original tire size.
As to your carb question, that will help some, but not as much as you sound like you want. I would start out by making sure you have a good air cleaner, a dirty one will rob tons of hp if you don't stay on top of it. Second, make sure that the thing is properly tuned. If you have your plugs & points set at the wrong gap that is a drain, bad plug wires, incorrect timing, etc. You need to check those before you go sticking a high dollar carb on. Just going off of memory here, buy your point gap should be .034, plug should be something like .017 and timing should be 6 BTDC plus 1 degree for every 1000 feet of elevation you are at. In my case, I am at 6500 feet above sea level so I used to (when I had points) time mine at 12*. I don't remember what the dwell should be, I am sure that someone will speak up. Another thing that might sound stupid, but is very simple to do is that make sure a plug wire didn't get put on a wrong cylinder. These are all things I would do before I ever bought a new carb. If these don't help, let us know and we can go about other routes of squeezing more HP out of what you have without getting too terribly expensive.
As to your carb question, that will help some, but not as much as you sound like you want. I would start out by making sure you have a good air cleaner, a dirty one will rob tons of hp if you don't stay on top of it. Second, make sure that the thing is properly tuned. If you have your plugs & points set at the wrong gap that is a drain, bad plug wires, incorrect timing, etc. You need to check those before you go sticking a high dollar carb on. Just going off of memory here, buy your point gap should be .034, plug should be something like .017 and timing should be 6 BTDC plus 1 degree for every 1000 feet of elevation you are at. In my case, I am at 6500 feet above sea level so I used to (when I had points) time mine at 12*. I don't remember what the dwell should be, I am sure that someone will speak up. Another thing that might sound stupid, but is very simple to do is that make sure a plug wire didn't get put on a wrong cylinder. These are all things I would do before I ever bought a new carb. If these don't help, let us know and we can go about other routes of squeezing more HP out of what you have without getting too terribly expensive.
Orangecrush
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'71 302 was likely "rated" at around 215. However, back then they more or less just made up numbers. Factory ratings meant nothing. Your 302 (assuming stock heads and manifolds) put out maybe 120 wheel horsepower on it's best day. Add the tall tires, and I think you see the problem. I mean, there could be a tuning problem too; but, I sort of think you're just noticing the re-gearing effect of increasing the diameter of your tires.
If you want more acceleration, you may have to look to gears. 32 inch tires aren't that big, but still make a very noticeable (slower) difference off the line. I have 35s and am running the 351w. It's a DOG off the line.
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all good pointers...& just to add..,
If it's flooding..., I would look at that first. Sounds like just a dirty needle & seat.., Or maybe a bad float.
"rich" mixture would do what you're describing
And, I had 31's on my '72 with an A/T & it scooted right along...so I don't think the 32's are causing your problem.
HTH B)
If it's flooding..., I would look at that first. Sounds like just a dirty needle & seat.., Or maybe a bad float.
"rich" mixture would do what you're describing
And, I had 31's on my '72 with an A/T & it scooted right along...so I don't think the 32's are causing your problem.
HTH B)
Crude dude
New member
Another thing you could try is to get a squirt bottle with WATER in it and when the engine is running spray a small amount on each exhaust tube directly outside the exhaust port on the cylinder heads. If it sizzles, this will tell you if that cylinder is firing normal. You will definitely notice if one is different. Next would be to get a cheap vacuum gauge and tune it up. S Bolt is definitely my superior Bronco fanatic but I think he may have the points and plug gap sizes switched. Approx .015 for the points and .034 for the plugs. It has been a long time since I have adjusted points so I may be completely wrong too. But were all on the same team trying to help. Good luck, let us know what happens.
I saw that too..... but figured he had a book.., since he just did a "build up....
It's .034 27 .017 .........plug gap....dwell....... point gap That's if its a '73 EB
It's .034 27 .017 .........plug gap....dwell....... point gap That's if its a '73 EB
All Bronco 302s from 69-75 are the same as far as the plug & point gap & dwell. My dad has a mechanic's manual for all V8 engines 1975 and older, that is why I say 69-75, it only covers up to 75. It is pretty neat, it gives all kinds of info and pictures of things like firing order for every engine, illustrations with cylinder numbers labled and on and on. I just gotta get him to give it to me.
Broncobill78
New member
The only Dwell specs *I* have are from my 1970 manual & that calls for 30-to-33 degrees. The Ford shop manual says the most precise method to adjust dwell on dual point distributors is to disconnect one set of points while adjusting the other. This way spring tension on the cam is equal. The example the shop manual gives is "where a 33 degree combined dwell is specified, the points are set separately at 25-25 1/2 to secure the specified 33 degree dwell." The shop manual also says NOT to use a feeler gauge to check the gap on USED points because the points are rough and the roughness "makes an accurate gap reading or setting impossible." Procedure is 1) follow the instructions of your dwell meter 2) operate engine at specified idle speed and note dwell reading. 3) stop engine and make adjustments to points. Decreasing gap INCREASES dwell. Check dwell again. 4) repeat as required until specified dwell is obtained. A2: My favorite way is to block off one set of points with a matchbox cover folded double right between one set of points. I also use a remote starter (between the 's' terminal and Battery), first making sure I have the truck in neutral! Level ground and a good parking brake are also good safety tips. I prefer adjusting the dwell while doing a full tune-up, and having all the plugs removed. This helps the starter spin the engine faster. (You can do this with plugs in, but cranking speed will be lower and the dwell meter will bounce more). Now simply spin the engine with the remote starter while having a good dwell meter hooked up. Placing the meter on the engine helps your viewing. Watch out for the fan!! You don't need the ignition on either, because the 'I' terminal on the starter solenoid gives voltage to the coil during cranking, thus driving the dwell meter. CAUTION! Because the coil is energized anytime the solenoid is engaged, do NOT do this with the cap on and the plugs in! The engine will momentarily fire (until you release the remote starter button). If you accidentally left the truck in gear, it will run your ass over! I go for about 24 deg. on one set of points. If the dwell is off, it is a simple matter to loosen the set ***** and adjust the dwell as you spin the motor. Yes, adjust as the starter is cranking so you can watch your efforts on the dwell meter! (Points closer = higher dwell) This approximates the car running at (albeit very slow) idle. After you think you're close, tighten the set *****. Of course, the act of tightening the ***** will change the dwell, so, once more, test after tightening. Now remove the matchbox cover and place in the other set and repeat. V-8 SB Fords have always been approximately 28-32 deg of dwell, and this method gets you very close to 30, and for me that's enough work for one afternoon. Or of course you could just convert to a DuraSpark and be done with it.
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Crude dude
New member
Duraspark, the ony way to fly. I think we have robbed this guys post. Turned it into our own.
HA...!!
Again..these answers take on a life of their own.....
h34r: /emoticons/[email protected] 2x" width="20" height="20" /> > ..I want Bill's hrs. ... 
