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I'm a new member and I wanted to ask about the dynotest results I just received. I have a mustang with 289 that's been rebuilt, bored 40 over , aluminum heads, intake new cam holley 4 barrel 600cfms , headers. The test results after 3 pulls were 180 hp. seemed really low. What else can I do to improve performance? Also this is auto c4 original rear end. Any tips would be appreciated, thanks
 

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Are you sure it doesn't say 280? A stock 4bbl should make that easy.
Something is very wrong. Is this in the car? thruigh the wheels? whats the gearing in the rear? What condition is you c4?
Ive got a 289 in a 67 fairlane, stock internals, rpm manifold, edel 4bbl, full length headers, 3.25 rear.
I would like to think your stang can could smoke my ride, but at this point, I think Ide walk on you.
 

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Welcome vintagestang..For anyone to help you we need all the details..What kind of heads,intake?..Specs on the camshaft? Compression ratio etc? If you have a printout of the dyno pull that may be helpful as well.
 

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I'm a new member and I wanted to ask about the dynotest results I just received. I have a mustang with 289 that's been rebuilt, bored 40 over , aluminum heads, intake new cam holley 4 barrel 600cfms , headers. The test results after 3 pulls were 180 hp. seemed really low. What else can I do to improve performance? Also this is auto c4 original rear end. Any tips would be appreciated, thanks
Chassis dynos are for tuning not for estimating Horsepower. Did you make any changes to the carb like trying smaller jets or changing the timing and distributer curve? Take it to the drag strip with some drag radials and you will get a better idea of how much power it makes. To gain some more performance change your gear ratio from the stock rear end to a 3.25-3.50 ratio.
 

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hello;

from a dead stop, mash your gas pedal to the floor up to 35 mph and tell us EXACTLY what it does.

give us ALL, ALL, ALL, Your specs, part numbers, brands etc..ie pistons, heads, cam specs.

unplug your distributor vacuum advance and plug it and leave it plugged.

give us your timing at idle then rev your engine to around 3000 rpm and give us your timing.

rev it slowly and tell us what rpm it quits advancing at.



iyeah i
 

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If they are chassis dyno numbers, especially if they were obtained through an automatic transmissions... they aren't that reliable. You lose a ton of power through the drivetrain, especially through a torque converter and auto trans.

That being said, it sounds more like a stock rebuild than a performance unit. Does it have headers and a large, free flowing exhaust? What kind of rpm does it turn? Details of the build?
 

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Discussion Starter #8
Thanks for your input on my dynotest questions. The rebuild was a top end kit through mustangs unlimited by edelbrock. I will post more details soon.
 

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That's what im sayin! ive got a 289 with a ba-zilion miles on it, rebuilt c4 with a b&m kit , 3.25 rear. Rpm manifold, 500 cfm edel, and full length headers with just glass packs bolted on the ends, pertronix and a flame thrower coil, and thats it, I think my flane would outrun the stang.
What exhaust are you running?
there was a thread here about a stang that was built to the hilt, and couldn't muster more than a couple hundred hp's, turns out, the exhaust system was to blame.
 

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Vintagestang, welcome to the Forums. :tup: I'll repeat what has been said, that HP numbers from a chassis dyno are next to useless. That's not what they're for. It's the info that's gained from it that is valuable, and allows increasing power to the rear wheels based on that info. Seriously, don't sweat dyno numbers. Post the dyno sheets, all the info about your build, and the rest of the car.

David
 

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We get the fact that you think your car is quicker..Not sure at how you arrived at this thought assuming you've never raced or even met?
Im sorry. I didn't meen for that to read that way.
I'm just saying with just simple bolt-ons vs. a top end rebuild, his motor should beat the snot outta mine. I didn't meen to sound like a jack-a$$.
I do hope you figure this out.
 

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Hello, I joined this forum for exactly the same reason. I have a 1966 Ford Fairlane with a 289 and a c4. Over the winter, I purchased the Edelbrock e-street kit, complete with cam, lifters, timing chain, gears, aluminum intake and heads. Topping it off is a Edelbrock 500 cfm carb. Bolted to the heads are a set of Hedman long tube headers. I also changed it over to a HEI ignition, and added a Edelbrock fuel pump. Needless to say, I was pretty excited about firing it up for the first time. Long story short, I expected a lot more get up and go. I checked my timing, and it was 12 to 14 before. I am at a loss, any help or advise would be greatly appreciated. Thanks, Mark.
 

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... Long story short, I expected a lot more get up and go.
Welcome to the Forums, Mark. :tup: The kit you installed has a peak tested rating from Edelbrock. Something like 321hp/327tq on a fresh and prepped block. We can do some analysis of what your engine needs; but the first question would be to ask — what did you actually expect? If your disappointment is due to chassis dyno numbers, then you already know the answer to that. But, if you're disappointed in how it accelerates on the pavement, tell us what you wanted, and then what it's actually doing, so we are on the same page to solve this. That may be all it has, or there could be a lot more left in it, or somewhere in-between.

David
 

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Chassis dyno numbers for an automatic trans car are WORTHLESS as far as relating to flywheel HP. A perfect example is my Shelby with a 331 that runs 11 teens in the 1/4. A local "Mod shop" had an open house and free testing on their new Mustang chassis dyno. I roll my car onto it and get a rousing 325 hp knowing I have over 500 flywheel hp. Open headers at 8,000 made all kinds of noise and attracted all kinds of attention. Next guy on the dyno had a hydraulic cam , pump gas 350 Camaro with a 4SPEED . He has a miss @5,500 but rolls 330 @ the wheels ! The dyno operator says it was the difference between my high stall convertor versus the manual trans. I say "never again" for the chassis dyno. I would say the OP has at least a 320 hp engine if checked on an engine dyno.
Randy
 

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David, thanks for the reply. A little more detail. When I pulled the intake an heads off the motor, it was apparent that it was freshly redone, it was absolutely spotless. I measured the bores, and there was no taper and no ridge on the top of the cylinder walls. Seeing the condition of the lower end, I decided not to touch it, and put the money in aluminum heads; then I found the kits from Edelbrock. Prior to taking it apart, it ran fine, and did not burn oil, I just wanted to hop it up a bit. As it was, it would not break the tires loose. After all I did, I expected it to smoke the tire at least. It is equipped with a fresh c4 and 2:80 gears. So, all my experience is "seat of the pants", and not dyno.
 

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David, more info. I am running an Edelbrock 500 cfm carb with vacuum secondaries and an electric choke. I have not ruled out that the secondaries are not opening....
 
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