Behold And Be Amazed At This $ To Hp Ratio

Discussion in 'Classic Mustang Specific Tech' started by jerry S, Nov 16, 2005.

  1. Stoich on gasoline is 14.7 while optimum power is usually achieved between 11.5-13 depending on too many variables to list here.

    I'd take care of timing first and then work on leaning out the A/F. I would think you should be able to get at lot (75-100 hp) more power out of that 351. A windsor with good flowing heads should easily put down mid 400's in both HP and TQ.
  2. Amen to that. Get a half-inch socket, loosen the distributor hold down to the point that you can just turn the cap, twist the cap clockwise until you hit your fastest idle, and go for a ride up a steep hill, trying to avoid kickdown. If you hear no ping, at the top of the hill take out the socket and tighten the hold down. If you hear ping, go back to the bottom of the hill and twist the cap counterclockwise and drive to the top again. Repeat until the ping goes away.

    If you want more, get a set of jets and go to the drag strip and rejet until you get your best trap speed. In your case I'd start by going down in size.

    These simple steps might not extract the last pony, but they will ballpark you a lot cheaper than paying the "pros" to do it on a dyno.
  3. 28 degrees doesn't sound like enough.
  4. I am told that the cam was installed using the "Lobe Center" method of degreeing and that it was installed on an intake centerline of 108º That is from the machine shop and also appears on the cam card.

    This is the cam card. Would one be able to glean the proper amount of advance from specs in the card? I have 11:1 CR. I am wondering if the tuner wasn't experiencing detonation at anything above 28 degrees total adavnce.
  5. A motor with a 236/242 @ .050 duration cam, 11:1 CR, aluminum heads, and 94 octane gas should not be pinging with correct total advance in the 35 degree range. Anyway, if you're curious, why not follow my previous advice, find that 1/2" socket and that 3rd gear hill and find out? You can avoid low rpm ping by using the heaviest advance weight springs and running lower base timing.

    Caution: potentially bogus half-backed internet advice ahead: Another thing, it's my understanding that a cam with 108 degree intake centerline and 112 lobe separation angle is actually ground four degrees advanced. To make it "straight-up" you'd have to install it retarded by four degrees. This would mean the intake is closing four degrees later, which would decrease the effective compression ratio and cut down on the ping threat. It would also cut down on low end torque, and move the torque curve higher on the rpm band. Higher torque at higher rpm naturally causes higher peak hp, because hp = torque x rpm/5252. (The last three sentences are true. It's the "my understanding" part that's potentially bogus.)
  6. no hills when you live 9 feet below sea level.

    I checked on the timing today. The tuner advanced it to 32 and 34 degrees total timing and found a decrease in peak HP so he backed it off. The A/F ratio was between 11-12. These guys know their stuff. they are pretty famous in Europe for the SuperCar race series.

    I am guessing that my problems lie in my transmission. Assuming a 25% drive train power loss, I have 400 fly wheel hp. A 400 hp motor is not easy to build. If it were, everybody would have one.

    I will swap out the C6 for a TCI Street Fighter C4, alum drive line and lightened rear gears and see what happens.

    By the way, the air gap turned out to be a dog compared to the much maligned Torker II. I had much higher low end torque with the TII.
  7. Really? When you're that low, isn't every direction uphill? Like standing on the North Pole, where every direction is South.

    Sounds like you've covered all the bases. 11:1 A/F is pretty rich, but not that far off from where it ought to be at low rpm under WOT, and 12:1 is even less so (more so?) You might want to read the plugs after some freeway miles, to make sure you're not grotesquely overrich.

    Whatever the case may be, it sounds like you've got a fun car. You should just enjoy it and leave the Dynojet alone.
  8. how much manifold vacuum do you have at WOT? a 650 might be a little small for a 351. I had a 600 carb on my 289 and it idled fine. Also what size long tube headers? are they 1.5", 1.625",1.75"? I would say get a vic jr intake, 750 cfm carb, and at least 1.625" headers. It seems like the peak horsepower comes in at a lower rpm than it should, so maybe something is choking it off, like the carb and manifold.Maybe the other guys can chime in on this?
  9. the headers are Hooker SuperComp (1 5/8 inch). The Vic. jr. is a great intake but I don't want to lose low end grunt to gain top end power. I have an AIR Gap on there now after swapping out the Torker II. The dyno shows that the TII was a better intake at low end compared to the Air Gap. Go figure.

    I am going to stick with 650. I am concerned that a 750 would bog. Even if I get a better top end, I don't want it at the expense of bogging down low.

    What I have decided is to get a better torque converter and send the carb to Jet Performance to be reworked. They can get it to 700 cfm and it will be tuned to the car's specs.

    I have conluded that my car is at the upper limits of what is possible for a non-roller cam 351W. The peak rwhp is 300 and that number is uncorrected. The engine is also new. I know that engines need to break-in before you will see peak power. I am also running a little rich. I might pick up another 10-15 hp once the engine settles in, the AF is leaned out a little, and any correction factor for the dyno is considered. 310 rwhp behind a C6 = 413 hp. That is about as much as you will see in a street engine. I compare my car to a 425 hp 351W available from That car has a roller cam which is good for 10-15 hp more than what you will see in a hydraulic cam, and a big carb (800 cfm). I am sure it is a high end screamer but it might not act so hot at low rpm. their next engine is a 396 stroker with a roller cam that makes 450 hp. I should not expect my non-stroked 351W to make more power than a 396 stroker with a roller cam and a 800 cfm carb. With this reality check, I am now very happy.
  10. Just out of curiosity, what gears are you running out back?
  11. 3.25
  12. First I would email a couple different CAM companies, such as Comp, Crane, and Isky cams. Tell them your spec sxactly and see what their recomendation is. I am willing to bet the cam is not matching the rest of yoru combo. Also SuperComp, I believe are not equal length that alone is worth some ponies. I didn;t notice what ignition your running.

    The other option is its balance. It is very possible it wasn;t and the internal vibration is keeping power down.

    But then again thats my 2 cents. I still would email the cam companies, but dont tell them you got a cam sound intrested. hehe

  13. The cam is a new Crower

    This stuff was actually selected, at least in the beginning. Then things went wrong. The machine shop originally went with World alum heads. The flowed the heads and selected the cam based on that. When they sent the engine back to my mechanic, he found that the heads leaked. He sent them back and got some Trick Flow Twisted Wedge cylinder heads. The TF springs can take have a maximum lift of 540. My cam's max lift is 538, which is within spec, but the springs still broke when they were breaking in the cam on a dyno. So they sent those back and looked high and low for AFRs which were no where to be found. So they "settled" on the RPM Performers. So while we know that the cam was perfect for the Worlds, it is unclear how well matched it is for the Edelbrocks.

    As for my ignition, I have an MSD 6AL and an MSD Pro Billet Dizzy.

    I am actually resigned to my combo being at its limits. This is a 400 hp engine at the flywheel and that is about as much as you are going to get out of a street engine running pump gas. Like I said above, the 393W stroker motors at makes 450 hp and that is with a roller cam. Their 351W roller makes 425 hp. I have about 400 with a non-roller cam. Instead of complaining, I am now pleased as punch. The fact that I am not getting the greatest amount of that power to the wheels is less than satisfactory but that is due to the tranny. When I get back to the US, I will swap out the C6 for a TKO. Assuming a 15% drive train loss, that is 340 rwhp. That is only 30 hp less than the 429 in 67GTA-FB429's car.

    Finally, the balance should be ok. The crank was rebalanced when the engine was hot tanked and I ended up swapping out the stock harmonic balancer for a nice SFI approved billet steel harmonic balancer.

    I am done complaining. For now, at least. ;-)