405 HP from stock cam Here is the link to the Car Craft tech article. 91 302 short block with stock roller cam, AFR 165 heads, 1.7 roller rockers, Stealth intake, 625 Road Demon, Dougs Tri-Y headers for a Falcon (Ouch those things were priced at $550 but probably not too far off from fitting into a Maverick). 405 Hp at 6200 rpm. Granted - this is flywheel HP and does not count for driveline losses. http://www.carcraft.com/techarticles/116_0307_ford/index.html Click on the sidebar articles at the bottom of the article. Specs for the stock roller cam are given along with head flow, carb specs and prices. If I were building the motor in this article I would spend a little less on another brand of header and fork out $125 for a B303 cam upgrade or similar hydraulic roller conversion cam for 351 non roller block. Also, a 351 probably needs the AFR 185's. Cleaver
I read that same article. It did have a stock cam but 1.7 rockers. Afr heads. I was a little doubtful at first but my roller 302 with KB pop ups, e303 cam, 10.5 to 1 comp ,1.6 rollers, roush 200 heads demon 625cfm carb dynoed at 370hp Then again magazines push there advertisers products too. I have a hard time trusting a product in a mag that is heavly advertised. I would have to be there to confirm a fair dyno and engine assembly before I had no doubts about it but it does seem possible but more than likely a little padding in those dyno numbers somewhere IMO
I can tell you with a high amount of certinty that you are not even close to 500 hp with the dyno programs and your specs. We run a 351W with factory N351 race heads and solid cam durations in the 285* , an 850 alky carb and 1-3/4" - 1-7/8" step headers into nearly open mufflers. The cr is 11 on alky. This results in a verifiable power of close to 550 + hp on a dyno at 7300 rpm and will still hold 500 hp out to 7600. The engine is capable of higher peak power but that is not always the best way to design an engine for the use it is put to. We use this engine to power a sprint car with one gear and need a cam that produces a very wide torque curve. Camming this way results in lower peak power but still a lot over a wide band. The torque of this engine is also in the 500 lb.ft range over the whole rpm range from the turn exit to the end of the straights. On a good nite and track conditions, this engine will lift the front end off the track nearly all the way down the straights. Now that would be a real street engine in a light car if you could tolerate the starting and idle. The engine was modeled on your 2003 pgm with head airflow inputted, carb airflow, cr, cam timing, headers speced and did come very close to the actual power. You must input specs very close to what you run if the pgm will allow, and is the only way for the pgm to have any reasonable accurracy. It is a good learning tool, however.
Ok, I went over the article and must say that I am impressed with the final results but I do argue that the heads did NOT give the 104 HP increase. If you take the time to read the article closely you will find that with a stock (and I assume untuned) carb and factory exhaust the engine produced 278 HP at 5200 RPM and 315 Lb ft of torque at 4100 RPM. I believe these figures BUT I also see that there is only 1100 RPM between peak torque and peak HP - this is a red flag to me - there should be a larger range between the two. Either they didn't register the true peak torque RPM or they didn't take the engine to its true peak HP range. Even if we accept the readings as honest readings they made changes other than the heads to get the 104 HP increase over the stock engine. They bolted on the heads using thin gaskets - that raised compression (they never tell you the size of the chambers on the new heads). They added a new carb - 650 CFM and tuned it for the best mixture on the dyno. They tuned the timing to an overall advance of 35 degrees - this was not done on the stock engine. They added a set of headers that are designed to give the best torque range in a 289 up to 7200 RPM (they were used on the Shelby GT-350). With those mods they gained 104 HP over the untuned stock motor with factory exhaust manifolds. I would like to see what the stock motor would have done with the timing increase, headers, larger, tuned carb and thin gaskets, maybe a gain of 40-50 HP ? That would leave the heads providing about 50 HP. A much more believable figure. Adding the 1.7:1 rockers is the same as installing a cam with 16.6% more lift and 4.8% more duration. So if you bolted these "Wonder heads" to your motor with the only change being the heads and rockers you might get 80 HP increase (if you already had headers). If you kept the stock exhausts you would be sorely disappointed with very little increase of HP due to the restriction in the exhaust. There are no "magic parts" that give you HP - and if you believe all the hipe you can get 40 HP from headers, 60 HP from an intake manifold, 10 HP from spark plugs, 30 HP from a carb, and 100 HP from a set of heads. Now if you add all that up you can push your 142 HP 1972 302 to 382 HP with no internal modifications! If you believe that cr@p then I have a bridge and some ocean front property to sell you in a green belt area of Arizona. PaulS *be a wise builder - critical thinking is better than faith when it comes to parts for your street machine.
Didn't realize the argument was about how much AFRs can provide. Thought it was about being able to get 400hp out of a 351. As you can see by the article on the 302, regardless of how they got there, that 400hp at the flywheel isn't heavy lifting for a 351, and you don't need to rev to 7000rpm. Yes they tuned, yes they changed some components, but the point isn't how much horse increase you can get from 165s, even if that is what they intended, the point is building 400hp that is very streetable on a small block Ford. Which isn't very hard. Nobody here is pimping afr 165s. We are just trying to get real hp numbers for a guy looking to build a motor. Let's not convict the magazine industry with conspiracy theories.
After many weeks of trying to access the mmb, I finally am able to be here again. It's still a hit and miss deal on my end, but have sure missed out on a lot of stuff in such a short while. Getting quite a chuckle out of some of the posts about being able to smoke the tires off and run wide open till the speedo needle twists off. To each his own I guess, this HP deal is quite interesting. Having built most of my engines from salvaged parts and pieces because of limited budgets, I don't really understand all the mumbo jumbo of figures and such written on paper. Good info from experience and fellow racers etc, has proved more productive for me. The fps, volumetric pressures, and such really is only needed if you are engaged in high dollar do or die type racing where every bit of usable HP is needed to win. Lots of stuff in the calculations of high tech programs etc. never takes into consideration the fact of getting the HP to the ground and the particular driving techniques etc. to accomplish this. Have seen many high dollar setups get beat by low budget but very fast combo's such as Bluegrass comments about. Most claimed HP increses by various companies are a invite to buy the product and produce profits for them. some are close to advertisements and most are not. Have found that things such as windage trays, balancing, and large capacity oil and trans pans, are of little value to the average racer. Cool cans and such, is another example of money wasted, and I have wasted a lot of it. Does make for interesting reading on the web though, Do know that when I bolted on a set of "out of the box aluminum heads " on a mild 302, it picked up a full half second on the track. Also Mavman switched to alcohol and flying toilet injection on his 351 and went almost a full second faster and from 114 to 121mph in the 1000ft. These add ons were not near as expensive as going through a extensive and calculated process of building an engine in the 40 to 50 thousand dollar range. Course thats why my endeavors are called "Backyard Motorsports" Can't say I would not like to have the time and bucks to build one of them there monster engines, but as said before, not needed for my situation and racing abilities. Still love to read all the tech stuff about how to do one though. Nuff said for now.
Here's mine, FWIW. '84 351w block 1 piece rear seal, stock 3.5" stroke crank, 4.030" JE/SRP forged pistons 14.2:1 compression, Victor Jr heads out of the box, Jr intake untouched (other than drilled for injectors), Eagle 3D 4340 rods (best investment a man can make for a GOOD 351w or 393), home-made windage tray & scraper, melling M83HV oil pump, Motorsport dizzy drive, MSD pro-billet dizzy 14 deg initial 33 total all in by 1000 rpm, Comp cams 35-803-9 camshaft (260-266 @ .050" .672" lift), Lunati old-style 1.6 roller rockers on 7/16" studs, K-motion springs 210 on the seat 620 open @ .700" lift, titanium 7 deg keepers and retainers. Run a best of 6.40 in the 1/8 at 108...and only turning about 6000 on that particular run at the 1/8 finish. Is it streetable? Define streetable. Idles at 1400, has 2" of vacuum, and uses 1 1/2-2 gallons of fuel every run including the drive to the lanes and the drive down the return road. Throttle response is too quick to drive on the street (at least for me anyway). ANY opening of the throttle results in instantaneous acceleration and driving in the pit area is sometimes a challenge at best. Is is fun? Heck yes it is!! It runs 140 degrees water temp all day long (well..as long as the fuel cell has fuel in it) in 100 deg weather and oil temp is usually in the 180 range. not my idea of a street/strip motor, but add a carb and it "could" be. I ran a dominator 1050 for a while and liked it...though power valves would have to be put in for it to be driven on the street at all, but it could have been possible. Do I believe that heads "could" be worth 100 HP? Yep...as dad stated, when I bought the RPM heads for the 302 I used to run, I went from 10.40 best to 9.50, with absolutely NO other changes. I figured that it was worth close to 100 HP...and the iron heads I had were decent castings that were "breathed on" some. They weren't all-out race heads, but they weren't stockers either. To add some on the head debate, I see it this way: If one is going to do a head swap, you have to remove the intake manifold, carb, heads, pushrods, headers, etc. Why not upgrade now when it's already off the car? If I was going to do another head swap, I'd also change to better headers, different carb, different intake, play with timing and jetting (free HP for the most part in tuning) to optimize the combination. For instance if you're going from stock iron to aluminum aftermarket heads, why on God's green earth would you put the stock intake back on and the stock exhaust manifolds? Sure, it'd be a true apples-to-apples comparison, but with the stock "wheezing" parts back on, the gains of even having changed the heads would be very minimal. BTW the stock 5.0L HO camshaft that carcraft used is very capable of the HP they stated. There is a thing called inertia...and pulse tuning. Air has weight, so does fuel. Add the 2 together in a fine mist and the speed of it going through an intake runner can make/break the combination. Those AFR 165s have small intake runners...which increase the velocity (speed) of the intake charge and therefore with that speed the charge goes through the valve, into the chamber/cylinder and the weight of it combined with the velocity gives it inertia. As the piston passes BDC and is coming up, the inertia of the mixture is still "pushing" it into the chamber through the intake valve, effectively "supercharging" to a certain extent. Also, those 165's have great low-lift flow characteristics which almost adds duration to a cam's profile....and allows that "heavy" fuel mixture a little bit more time to enter the chamber. We all know the more air/fuel we can get into the motor, the more torque you can make....and most of us also know that HP=torque x rpm/5252. Just throwing parts at an engine sometimes won't do a thing but ding the ol' pockebook. Dad and I both learned the hard way!
