I have a 78 bronco with a 460 7.5L v8. I am obviously a power junkie but want more hp and am looking for suggestions to help me reach that goal. I also hope to improve the fuel efficiency as much as possible.

thanks

 

well which is it power or mpg

 

I aree with drunkenmonk...more power and fuel efficency usually don't go together. Of course that is assuming you all ready have everything in a fine state of tune.

Deen

 

Truth be told, I guess Im after just making this thing as much of a beast as possible. Power wins over efficiency

 

open element airfilter will improve milige and power

also banks makes an muffler system that makes a whole lot more power and is said to improve ecomony.

 

guitarloser,

It's hard to say without knowing a little more info- how much power do you want & how much do you want to spend? Here's my suggestions, assuming the following:

1) The 460 is totally stock & about the same vintage as the Bronco.

2) You want to spend a limited amount of cash, but are willing to ante up a few bucks here and there.

3) You are like the 99% of us here and cheerfully rush in to working on things you know little or nothing about.

4) The 460 is relatively healthy- compression in all cylinders is fairly close, & engine is in decent tune (carb OK, timing OK, plugs, wires, filters, etc. all good). No point in trying to "warm up" a 7 cyl.

The first thing I would suggest is a better air filter & housing. Some of the Ford housings can be modified to flow better, removing obstructions & so forth, and you can scrounge another snorkel from the junkyard & have a two inlet housing, using tin snips & a couple of rivets/screws. Even better, duct the air cleaner to a source of cool air & pick up some free hp. Most people don't like the looks, though. If you're so low on bucks that your wallet is moaning in pain, try flipping the air cleaner lid upside down and/or using a taller element, if the hood will clear (check carefully!). Otherwise, use any std. 14" open element chrome housing & a 14" x 3" or 4" element. I'm partial to K&N filters, but a lot of people here aren't. I have not noticed excessive bore wear on anything I've torn down that used one.

Second, junk the stock manifolds & lousy exhaust system and use headers. By now the stock exhaust is probably long gone...but a lot of "replacement" pipes and Midas Muffler,etc. specials are just as bad. That's not to say that Midas doesn't/can't do good work, but just like anywhere else, you can get a bad install. Also, if the exhaust is bent up using bend cards or a preprogrammed layout, they can be fairly restrictive. As to headers, use a good brand & install them correctly; try 2.5" or 3" dual pipes with a good pair of mufflers, like Dynomax or Flowmaster, and (my preference at least) full tailpipes. If you can't/won't get headers, do the rest of the exhaust properly & keep the manifolds.

After step 1 and again after step 2, it's a good idea to check carb jetting & ignition timing. Both may/will need to be adjusted to take full advantage of your mods, unless the timing/jetting was off to begin with.

Third, if you're willing to dive into the engine a little bit: replace the timing chain & gears!!!!! As has been covered in several posts, during the 1970s, Ford (and others) routinely installed timing sets that retarded the cam timing 4 degrees or more. Add on the wear & stretch of a used timing set anyway, & you get a SERIOUSLY lame & sluggish engine with dismal economy. In my view, this is the best thing one can do for a 460 for the money, bar none. A couple of things to note, though: first, make sure the set you get isn't retarded itself. A lot of the "replacement" and cheap ones are. See the other threads in this forum for more info. My preference would be the Cloyes Tru-Roller or the Comp Cams (re-packaged Cloyes!), but they are pricey. Also, get the gasket set, sealer, proper balancer puller/installer beforehand....and as long as you're doing this anyway, replace the water pump and antifreeze, and belts, if they have some miles on them. Not much more work to do this...which leads me to #4.

Fourth: As long as you're this far, consider a new cam/lifters. The originals are by now likely worn, & not that great anyway, due to production & emissions restraints. My pref. would be for a split pattern cam, due to those dandy Ford exhaust ports (all sarcasm intended), something like the Crane 353902 with .487/.518 lift 204/216 deg. duration @.050, or the Comp Cams 34-231-4 with .505/.505 lift 210/218 deg. duration @ .050. Keep in mind that with the low compression of the average stock 460, a more radical grind will just kill your "effective" compression and all your low end torque as well, along with vacuum, idle quality, mileage.... Any of the major cam manufacturers can recommend a good cam based on your combination, better than I can. I'm not crazy about the cheap cam kits from PAW, Summit, etc.- the quality isn't TOO bad, as a rule, but the ramp design is ****-poor for the most part and they usually require a healthy amount of bushing/offset key, etc. to get them installed where they need to be. I would also recommend that you don't cheap out on the valvetrain- get the correct springs, and machined locks (not stamped). Probably wouldn't hurt to get the correct retainers as well- although depending on the spring you might not need them. All that being said...there is a note to keep in mind, as always with Ford, and that is the nonadjustable valvetrain. There are at least four different ways to correct this: converting the cyl. heads to screw-in studs & guideplates, adjustable or custom-length pushrods, shimming the rocker stands, or using the Crane conversion kit. Converting the cyl. heads is ultimately the best solution, but takes this out of the "done in one day" timeframe. Adjustable pushrods are expensive and heavy; custom length pushrods are fine...if you can measure properly. They also don't always fix a valvetrain geometry problem by themselves. Also expensive. Shimming the rocker pedestals is the cheapest, about 10.00 for the kit, but takes a little time to do; also does not allow you to adjust the valves, except by reshimming. The Crane conversion kit, about 83.00 from Summit, works very well, with mild cams and spring pressures. You would want to check with Crane to verify this, but I imagine just about any truly streetable cam would be fine. I have used the kit with two more radical cams & both are still running fine after four years. This kit doesn't require roller rockers, though they can be used if you want.

And finally, if ya just didn't spend enough money already: try a Holley 750 vac. secondary & a Weiand Stealth or Edelbrock Performer RPM intake manifold. Truthfully (and I know I'm gonna hear about this one!) the factory 4 bbl. intakes from just about any brand are hard to beat under 3500-4000 rpm. There are a couple of exceptions/bad ones, but for low speed airflow, they do very well (and yes, I have done some work on a dyno to verify this, as others have as well). I've seen a lot of guys go out & add the aftermarket intakes/carbs to stock engines expecting huge gains, and been disappointed. That's not to say they don't have their place- factory cast iron intakes are ungodly heavy, harder to port, and are usually hopelessly outclassed by 4500 rpm. They aren't nearly as sexy looking as a aluminum intake, either- but they are cheap, and common. The aftermarket intakes also work better when you add headers, exhaust, and cam as part of a total combination. For what it's worth, IMHO, the Edelbrock Performer RPM is just about equal to the std. Performer at low rpm & blows it out of the water upstairs...at least on the three engines I've been able to compare them. The Weiand Stealth, for the std. heads, not the CJ heads, will be just as good. However, the std. Performer is much more common on Ebay- though the prices they often go for are pretty close to what a brand new one costs-go figure. As to the carb, the Holley 750 vac. secondary 3310 works great on the street, can be found cheap used, and is forgiving of tuning errors. You can use or should I say install bigger carbs, but be very careful about the booster signal- the average 850 Holley is generally a double-pumper and has a terrible booster signal. If you know what you're doing and are familiar with carburetion principles an 850 or even larger can be used very effectively with no penalty, but the average person doesn't know/care what to do or how to do it. I doubt the average 460-in-a-truck is ever going to need any more than a 750, anyway. If you are into four-wheeling at steep angles, and have gobs of liquid cash, look into the Holley fuel injection units, or convert over to a stock Ford EFI...which is a whole 'nother ball game.

Lastly, if you've got a point distributor, I'd convert it over to electronic (if it's in good shape); otherwise, the Ford Duraspark units work pretty well, and can be combined with a MSD box. Again, I'm probably going to hear about it....but a lot of people spend too much money on their ignition. If it fires the plug consistently and well, through the limited RPM range used on the street, and you can get the advance curve where you want it....what more do you need? The less you spend on extras, the more $$$$ you have for gas, beverages, tools, etc.

Well, that's my 2 cents....hope I didn't talk over or under your head......Now, aren't ya sorry ya asked?????????

 

ok?... because i got a bone stock 460 in my 84 f-250 and i'm looking to do the same thing....boost the performance and efficency a little. un-retard the cam gears...then add a complete new exhaust system including headers and a true dual flowmaster 2.5" all the way back. then get a new cam and lifters and definetly a new 750cfm carb.

dont worry about the intake manifold for now and let it breathe more.

i've already got electronic ignition but on my carb i got an auto choke....would a conversion to a manual choke be hard?

and there is a smog pump on the motor....does this also take away from fuel economy?

am i missing much here?

 

also...do roller rockers help out?

 

Blacksilo,

Depends on your mech. ability. If you're just starting out, I'd do the exhaust first; do the timing set, cam, & lifters later on. Actually, if it was me, I'd do the exhaust first anyway, simply because you'll never get the full potential out of any cam, unless it's very close to stock, until you free up the typical factory exhaust, which is full of compromises, and get rid of the Ford manifolds. Most (not all) Ford exhaust ports and manifolds are not particularly good because they were designed to clear the narrow engine bay/shock towers in Ford cars (and if you've ever changed the plugs in a BB Mustang, having to actually lift the engine up several inches to do so, you'll know what I mean!!!). Unfortunately those of us with trucks got stuck with them too. Sure, you could simply do the timing set by itself, but then you'll have to do the whole thing over again for the cam/lifters. As for the intake, yes, I'd leave it until later on, unless you happen to find one @ the right price.

As for the choke, when you swap to a Holley or whatever, you can equip it with an electric choke; some already have them. It's a one wire (positive) connection, just tap into the existing wire for your current choke. If you have an auto choke that uses heat, not wiring (I don't recall offhand what you would have, sorry), then run a new wire that is powered only when the ignition is on. If you want to convert to a manual choke it's no problem, just mount the cable inside the truck, find a place to go through the firewall, and attach it to the Holley, which comes with a little bracket on the vacuum secondary (looks like a lawnmower setup). However, if you got a Holley that has an electric choke, it likely won't have the bracket, or the lever assembly for the choke, & you'll have to get them. Holley still makes the parts, but I'd check a carb shop first for used pieces. I'd tape up the old factory wire (again, if you have one) to keep dirt out in case you swap back to original. Truthfully, I'd opt for the electric choke, I like the convenience, and they are adjustable.

As to the smog pump.....I hate to cop out, but I believe it is illegal everywhere to remove existing emissions equipment. That being said, the purpose of a "smog" pump is to add extra air into the exhaust gases in an effort to relight & burn off excess unburned hydrocarbons. They don't actually use a lot of horsepower to drive them. Of course they don't add anything either. My main objections to them are 1) they tend to go bad & seize up in inconvenient times/places, like 70 miles from home; 2) they change the nature of the exhaust gases, making it harder to tell specifically what is happening during combustion, & therefore tuning (there are ways around this, but not really for the avg. guy in his garage); and 3)it's just one more piece of crap to work around.

Roller rockers.....boy, if you want to get people in a bad mood, bring them up at a BS session an' watch the arguin' begin! The short answer is, maybe. For the average STREET USE ENGINE, like your truck, I'd say save your money. They do have several benefits: they have less friction, which does help. This is a MUCH greater factor on a high hp engine with sky-high valvespring pressure. Not saying they won't help a street engine, just not as much, and I think it's debatable whether you'll ever recoup the expense of them with better mileage. The second benefit is that the amount of oil pumped up to the valvetrain can be reduced greatly, IF you have a solid or solid roller cam, and roller rockers. This, again, is high end stuff. Third, they are stronger, at least the GOOD ones are. Some of the cheap ones are so inferior in terms of metallurgy that they have to be made very large, which causes all sorts of assembly & clearance problems. Fourth, they tend to slightly reduce oil temperature, not really an issue for the street. Fifth, you can run higher cam lifts with them, which is a street issue, if you have a good combination. For the avg. person with limited experience, I'd say ask the cam company as to what they recommend, keeping in mind they want to sell parts. Under .500 lift (at the valve) you likely don't need to worry, but you always want to check the rocker slot clearance to verify, regardless what you are running. Sixth,& most important, they offer the ability to use different rocker arm ratios, depending on the engine. If you own a Chevy....you can get a lot of options here. On Fords, there's not nearly as much. For 460s, I believe Comp Cams offers 1.73 (stock ratio) and 1.8 in their very expensive line. Otherwise, I think you will get 1.73, or 1.7, with everyone else.

To make a long, rambling story a little longer....most people buy them because they want to be able to say they have roller rockers. If you had to replace your existing factory rockers on your truck....and you wanted to convert over to an adjustable valvetrain....and you were going to choose a fairly stout camshaft....and you don't mind getting taller valve covers....then I'd say it was OK. Especially if you have lots of cash. Otherwise, no. The Crane Energizer cast aluminum sets aren't super expensive, around $200, and hold up pretty well (and work with the conversion kit i mentioned previously).

Now, aren't YOU sorry you asked???!!!!!!!!!!????

 

thanks dude, there is only one only thing that is hindering my gas bill...my diffs are geared at like 4.56...so i cruise on the hiway at about 3500rpms going 65 in 4th gear

To get a new set of diffs geared at about 3.13 it would be about 1000 bucks right?

having two different geared differentials would reak havoc on your transfer case...say you had a 3.73 in the rear and a 4.56 up front....and you went to go 4 wheelin....what exactly would happen?

 

what about just replacing the ring and pinion gear instead of the whole diff

 

Blacksilo,

Hmmmm, an F-250.....What are the diffs, a Dana 60 in front & a Ford 9" in the back? Around here, Illinois, it runs about 400-500 per axle in labor, last I heard, with the axle installed. In other words, drive it in, drive it out. Gears, lockers, parts, etc. extra. Removable units, like the 9", are a little cheaper because they're easier to do on the bench. For what it's worth, I just rebuilt the Dana 44s in my Scout II, changing from 3.54s to 4.09s, and adding a LockRite in back; the cost of the gearsets, two 4-series carriers, the LockRite, and basic bearing packs, shims, etc. was $912.25 from Randy's. That doesn't count new ball joints, assorted bearings & seals not included, gear lube & sealants, rebuilding the hubs, U-joints, the new bearing replacing the one I screwed up, and the Moser axles. Or my labor, if you can count it. However, I'm pretty certain that they're going to last for awhile.

Also, if you have a high pinion front axle, you're lucky...but the gearsets are more limited in availability of ratios, and they cost more.


As far as the carrier, it depends. For a Ford 9", if I remember correctly, rather than change carriers, the gears are made thicker or thinner to compensate- it's been a long time and I really don't remember for sure. On my Dana 44, the cutoff is 3.92- any higher and you have to get a 4-series carrier..or you can get special "thick" gears, but the cost difference is more than if you get the reg. gears & the new carrier. Also, "thick" gears are very limited as to the available ratios, and they may not come in high-pinion styles for the front axle- I couldn't find any listings, anyway. The Dana 60 is similar in layout but the cutoff point is different, and I think the same carrier is used for 3.54 to 4.10 ratios.

To sum it up....it actually might be cheaper, depending on your truck, to get taller tires. I swapped gears when I went to 33" tires, to keep the powerband decent enough to tow, off-road, and so on. Of course, it wouldn't be cost effective if you had to put a 6" lift on to clear the tires. With your combo, it wouldn't hurt too much to drop down to an effective 4.10 or even lower, if you're not towing. Another option might be to swap in an overdrive trans, if you can find a cheap one. I think the only automatic OD for the 460 is the E4OD, early nineties (1992?) and up ....pricey, not super strong without mods, and requires computer control (talk to TCI, B&M, Phoenix,etc. for details)..otherwise, I'd look at manual setups, which I am not familiar with in terms of Ford trucks, but I'd bet something is out there, in a F-350 or F-SuperDuty fron the late eighties, that would be easy to find and bolt in without too much hassle.

Lastly, a small difference in ratios won't hurt- like 4.09s in a front Dana, and 4.10s in the rear Ford 9". You would want to verify with Randy's or one of the other big vendors but I think the rule of thumb is 2-3 % difference would be OK. 3.73s in back (I presume to get better mileage in 2WD) and 4.56s in front will lead to expensive problems after about two minutes of driving. Maybe less. Seriously, at best you would toss a U-joint, if they're weak; at worst, the T-case will be wrecked, or axle internals; pretzeled drive shaft; something's got to give....if you're low on $$$, save up for both, or do the rear axle, disconnect the front shaft, and save $$$ again til ya do the front axle. Not impressive to look at, but who cares? Hope this helps....

 

well, i dont think it's a ford 9"... it's probley leaning more towards a dana 60 in the rear and probley a dana44ttb in the front...that's just what i'm guessing from the other post where i asked that question.

that info helps out a lot...i want to put a locker in the rear and i was planning on getting bigger tires later on down the road. i do tow but it is very occasionally in the winter but during the summer i pull jet skis and a dory boat that all in all weighs about 5000 pounds.

thanks for the help, homespun91....looking at about $2000 for both front and rear?

 

No problem...I help out whenever the voices in my head tell me to!

I think you're right about the Dana 60 in back...I seem to recall a friend's F-250 from the mid eighties having a 60.....If you do drop from a 4.56 to a 3.73, or lower, it does mean a new carrier. I guess the only other thing I could add would be this. Before I spent the $2000, I'd take a very hard, objective look at the truck and decide how long you want to keep it, how good shape it's in, & so forth. Realistically, you'll never get anybody to pay you for all your work & money invested, so if you plan to move on to a different truck in 2-3 years, it's kind of pointless to spend the cash. Even as a daily driver, I bet the extra cost of gas used will be equal or less than the cost of the upgrades. Of course that doesn't factor in personal satisfaction & fun. As much as I like Fords, an '84 isn't really old enough to be a "classic" and isn't new enough to be worth much. Of course there's always exceptions. If you really like the truck & it's a keeper, go for it. As far as the costs, you'd have to check around. If you have a shop specializing in 4WDs, the labor might be less. Where I live there is one shop, in a town of 125,000, that really knows axles, & it's a heavy truck shop. They will do light axles....but it's not their thing. As to the parts, a 4WD shop might cut you a good deal if they're doing the install as well. Also take a look at Four Wheeler or other mags & check out some of the package deals. I can say that Randy's Ring & Pinion was good on price, & threw in the pin for the locker for free, normally 30.00. If you go to their website they have all sorts of calculators to determine the best ratio to achieve a certain rpm, calculate speedo errors, etc. If you wanted to investigate a tire size change, these will help. I don't think there's a specific calculator to do that, but you can try different sizes & see what effect it has on rpm at a specific speed. Of course, a F-250 probably has what, 30.5 or 31" tires already? so maybe it's not an option....