460 should have 500 hp but 1/8th mile calc says I have 300?

I have a 10.5:1 cr 466 with edelbrock performer rpm heads, cam, intake with a holley 800cfm carb. Its in a 67 Ford truck with an automatic, 3.54 gears and 27 inch tall tires. I just took it to a local 1/8th miles strip. I had some tranny troubles (shifting from 2-3) but the best time I ran was 9.5 seconds. I estimate the truck to weigh about 4000 lbs. This build should be closer to 500 hp, but based off the time Im finding that I have 300??? Like I said I did have some tranny troubles which probably affected the time a bit, but still Im baffled. Any ideas??

Why do you presume this should be close to 500 horsepower...?
I certainly don't see that at all with all "Performer RPM" components ... MAYBE just over 400 or so. You must be believing the advertisements.

Maybe your truck is 4500lbs or more if you are just estimating it also.

Im basing it off of similar builds that Ive read about in magazines using the same parts that acheived 500 hp on the dyno.

truck-collector wrote:Im basing it off of similar builds that Ive read about in magazines using the same parts that acheived 500 hp on the dyno.

I got the same parts as a guy that can run a 4 minute mile .

Ruff crowd,

Truck Collector All the parts can be there and the tune be off or one part miss matched and your hp goal may be far from what you are looking for.

Most new combinations go to the track for the first time and are disappointing. But after several trips to the track , tuning ,leave technique, gear ratio change, things finally come around.

But the engine combo you have I doubt like Randy M said will make that kind of power.

I don't see your converter listed, and if it's too tight not leaving at toque peak or at least close it will be a pig on 60 ft and that will kill your E.T.

Give us some more info.

track elevation? air density? brake caliper dragging?...................

After reading my post I realize its a little vague and left out a lot of variables. It was late when I posted it. Either way, theres enough builds out there that show these parts can reach that horsepower level. I had this engine built for me when I was in my early 20s -about 8 years ago-by an engine builder. Since I built the truck for the street Im not going to worry about it. This was the first and only time its ever been to the strip.

I knocked over a second off of my E.T. when I discovered that my carb was not opening all the way. It is called workin' the bugs out......

i have a edlebrock headed 466 too. it ran a 12.5 actual in byron, 1/8 was 8 flat....using drag times correction bullcrap it came out to 12.3,,,gears are 327 with 26 tall tires. weight was 3250 with me in it. carb is a 750 vac sec. hopes that helps you gain some perception. bobn

One more thing to think about is if you have a 500hp engine and the drive train is not set up for it,it is not going to show the 300hp is more than likely rear wheel hp and not bad for a street ride.

need to post more about your build and have the truck scaled.

The RPM cam is a rather poor choice now days.

What Convertor and what have you done to tune the engine?

You need at least 4.11 gears get your trans problem corrected and what type of convertor do you have .Check your ignition timing and is your carb opening all the way .Do you have slicks by the way?My 3400 pound comet runs 7.26 in the 1/8 466 edel heads 11.67 compression 4000 stall 4.56 gears solid flat tappet cam.Sometimes you have to work hard to speed up your vehicle Doug

what is average cranking compression ?? 3 things make them run, spark, fuel, compression get theese three right and u should be able to make what ever the combo is capable of

Thanks everyone for your input-youve given me a few things to think about-action items- check carb, check compression, get tranny fixed. The convertor is a hughs rated at 2400 however I think I need more because even w this convertor the truck is ready to move as soon as its in gear. And that just doesn't seem right. I actually feel sort of silly having posted this and I was a bit nieve to think I'd get top performance right out of the box. Maybe ill even take the truck to the scales to see how much it really weighs. Title weight is 3910 but that was w the old fe and cast iron 4spd and dual tanks all of which are gone n
ow.

truck-collector wrote:Thanks everyone for your input-youve given me a few things to think about-action items- check carb, check compression, get tranny fixed. The convertor is a hughs rated at 2400 however I think I need more because even w this convertor the truck is ready to move as soon as its in gear. And that just doesn't seem right. I actually feel sort of silly having posted this and I was a bit nieve to think I'd get top performance right out of the box. Maybe ill even take the truck to the scales to see how much it really weighs. Title weight is 3910 but that was w the old fe and cast iron 4spd and dual tanks all of which are gone n
ow.

We would really like to hear what you find............... Keep us posted.

Thanks everyone for your input-youve given me a few things to think about-action items- check carb, check compression, get tranny fixed. The convertor is a hughs rated at 2400 however I think I need more because even w this convertor the truck is ready to move as soon as its in gear. And that just doesn't seem right. I actually feel sort of silly having posted this and I was a bit nieve to think I'd get top performance right out of the box. Maybe ill even take the truck to the scales to see how much it really weighs. Title weight is 3910 but that was w the old fe and cast iron 4spd and dual tanks all of which are gone n
ow. You got to start with a pass down the track and try to improve from there. There is nothing better than shaving off a tenth each time you go to the track. It keeps me awake at night.

Once all the mechanical stuff is correct it is usually a matter of learning what the combo likes; launch rpm's shift rpm's.... On more than one vehicle I have built I have dropped a complete second or more off my ET's just by figuring out what the combo wanted.