For example, my best time is a 14.93 at 91.71 mph. The car has 3.31 gears with that run being on 26.5 inch tall tires. Is there any way to determine a rough RWHP figure from those stats?

On a separate but related note, with a trap speed of 91-92 mph pretty consistantly, should I be able to squeeze any more ET out of this thing? My 60ft's are not stellar with my best being 2.271 but I just don't have a lot of torque to work with and the gearing isn't much help. But it's a stocker/show car and will stay that way so I have to work with what I have.

Rich,

If you know the weight of your car you can figure out the HP from that and the time slip info.

I'd think there would be plenty more left in your combo. It's the 350-horse 327, right? You've got a 4spd as well?
What RPM do you leave at? You can always try leaving at a higher RPM and see how that does. If it blows away the tires, then you could go with some better tires and just mount those up for the strip trips. Having made the switch from stock tires to decent track tires, I am now a firm believer in tires as a method to decreased ETs.
The simplest thing to go after without altering major parts would be the tuning. I'm sure there's a lot of work you could do in regards to timing that would be invisible to the eye, yet net you some results on the track. I recall that changing advance weights was worth 2 tenths for us.

The weight of the car is right around 3600.

The best runs were made with DOT slicks and the launch had no wheel spin at all. I launched at about 3500 and rode the clutch a bit to keep the revs around 3000 all the way to full clutch engagement. If I were brave, I'd wrap her up to 4500 or so and dump the clutch but I'm just not going to do that with this car. smile.gif I shift at 5800 and I can go through the traps at 6500 or so in third or grab fourth and go through the traps at about 5200, it makes no difference in ET or MPH for some reason. If I could launch with just a touch of wheel spin with these slicks I'll bet I could noticeably drop those 60ft's and thus ET. I haven't had too many runs on the slicks to work the launch out well.

I think I have the timing and distributor maxed out. It really pulls hard from 4000-6000 with the timing maxed. I have 10-12 initial with 36 total mechanical all in by 3000. That change alone really woke the car up. I have tried more initial and found it to really hinder the car. I have tried replacing the heat riser flapper valve in the exhaust system with a blank plate with no flapper valve and it made no difference so the car now has the correct heat riser back in place and my best run was made with it in place. I suppose without headers it just doesn't matter that much.

Modifications I do allow myself for the track are Pertronix (no noticeable difference ET-wise but the engine is smoother at higher RPMs I think) and a K&N filter. I run the valves every Spring and I've never found any of them off. I have tried lashing them loose (about only 1/8 down from zero lash) to tight (3/4 down from zero lash) and everywhere in between and found no difference. Someone once suggested a loose lash could provide some high end advantage.

I have not played with the vacuumm secondary spring but the carb works so smoothly that I think a softer spring would bog and a stiffer spring would limit top end. Chevy and Holley did know what they were doing when they designed this thing I guess and since the engine hasn't been modified mechanically it's initial settings still work well. I could play with the springs just to know for sure. I haven't messed with jetting either but it does not seem starved at the top end.

And yes, it's my coupe with a 350hp/327ci and a 4-speed.

If it helps, my 1/8 info on my best run was 9.56 ET with a 73.13 MPH stat. That's almost 20 MPH from 1/8 to 1/4 mile marks, isn't that a good sign of no drop off at the big end?

you can estimate your Flywheel Hp from your 1/4 mile trap speed.

(.00426 x MPH)^3 x weight = HP

It's most accurate at 100 mph. This equation understates HP the farther north of 100 mph you get.

Example:

(.00426 x 91)^3 x 3600

(.38766)^3 x 3600

.0582576 x 3600 = 209.72 HP

multiply by .8* to get RWHP = 167.78

My 91 LX was 190 rwhp it ran @ 3400lbs et was 14.20 @ 95 stock so I would think your making around that.

214 RW HP

http://www.prestage.com/community/Car+Math/ET+and+Horsepower+Calculators/HP+from+ET+and+Weight/default.aspx

http://www.prestage.com/community/Car+Math/ET+and+Horsepower+Calculators/Calculate+ET+and+MPH+using+HP+and+Weight+/default.aspx

Divide 214 by 80% and you're making about 268 net horsepower at the flywheel, which is about right for an engine rated 350hp gross.

i get 216.72 rwhp using the 91.71 mph pass and 3600 race weight. and you should be able to turn a 14.86 e.t. so it looks like you are using darn near 100% of you available horsepower efficiently.

i myself have found hp and e.t in just the holley carb. to give you an idea i was able to improve my trap speed from 102 mph to 105.93 mph just in jetting and secondary spring changes. and this isnt the only time....just most recent.

My buddies 73 318 Challenger comes in at about 3600lbs or so and has ran a best of 15.23 at 89 mph. He dynoed 180rwhp and 292rwtq. So I think the previous guess of between 190 and 200 is about right.

Guys, There is a basic flaw in your old Chrysler (.00426 cubed) formula. Trap speed was changed by NHRA since this was originally formulated. If you first multiply your current trap speed by 1.0072 you will get an accurate trap indication according to Meaux Racing heads, which appears to be a fairly accurate. Next the average drivetrain loss for a manual transmission is more along the lines of 13%. The 20% figure is a "Turbo 400" loss figure. Torque converter slippage changes everything. I came up with 219 flywheel H.P. and 190.8 RWHP. The current trap speed is the average speed at 1287 feet because they moved the second speed trap photocell to the E.T. line, where it used to be 66 feet past the line and gave true 1/4 mile speed. Rich, i think your 65 Chevelle is the best color combination produced in 1965. The 350 H.P. - 327 is definately capable of much better performance than your getting. Steeper gears would most likely get the most performance of anything you could do without major work. From looking at the pictures of your car it appears to be a concours restoration primarily. This car would really respond to 3.73 or 4.10 gears as these motors produce most of their power up high. I think your car capable of low 14s @ 100 MPH at 3600 pounds which seems somewhat heavy for this model as NHRA lists this car at 3166 + driver. Still, this a beautiful car. Love the goat too.

That 3166 weight seems awfully low. I'd really have to strip the car down to loose that much weight. My weight was taken with the car with a full tank, me, the spare and all normal equipment in place. I weighed it on a certified scale so I'm pretty confident the weight is accurate. Stripping the interior and losing the spare could net a savings of around 150 pounds and with me stepping off the scales would save about another 170. Maybe I had a bunch of junk in the trunk at the time. The scale is about 5 miles down the road so maybe I'll go scale it again. The SS does weigh noticeably more than a 2-door sedan so I have to wonder which body style the NHRA used to come up with that figure. Do they assume the car is stripped of interior, spare, jack and other unneeded equipment?

I'm sure ETs would improve with a gear swap, but I've decided not to mess with it, mostly because the wagon project will result in a car I can abuse a little more without fear of destroying irreplaceable (number matching) driveline components.

Maybe I'm just dreaming, but I think the car could do solid mid-14's if I could bring myself to abuse the driveline more (like dump the clutch and shift more aggressively). I'm happy to take home slightly slower times and keep the car in one piece though! :D

I know a number of guys who have owned both 65 and 67 Chevelles with L79s that ran consistant high 12's in stock classes back in the day. Of course even those classes allow for more modifications, such as headers, which I don't allow myself to do.

I get 217 RWHP from . 14.85 is as quick as it will go. Your actually using 98.65% power to the ground. You need 260 RWHP at that weight to run 13.99.

I have a program, spread sheet anyone can use. Just punch in your ET, MPH and WT and it calculates all this for you. It can even do nitrous too.

CAR.xls

try this, just cahnge your #'s in the blue at the top

sorry it didn't work. I can forward this to someone that's more computer smart then me and maybe they can get it on here. It's an excell spread sheet.

Rich, headers make a HUGE difference. With stock exhaust, you're probably getting about all you're gonna get at 14.9's and 92mph. I think I read where a 66 L79 Nova turned 15.1 at 92mph back in the day for a magazine test, and a Chevelle is certainly heavier. The L79 cam is pretty much outdated by now as well. Headers, a modern cam grind, and sticky tires would no doubt get you well into the 13's, but as you said, that's what the wagon is for! smile.gif I think 14.9 is pretty quick for a bone-stock small block chevelle.

Originally posted by Georgia69:
I think 14.9 is pretty quick for a bone-stock small block chevelle. ..I agree graemlins/thumbsup.gif

I agree, I'm just curious if there is any more in there that I haven't made use of. I don't think so, but I'm certainly no expert!

No one has commented on my 73mph @ 1/8 vs. 92mph @ 1/4 stats. Is that good, average or below average? I thought a 15mph jump from 1/8 speed to 1/4 speed was good so a nearly 20mph jump has to be pretty good. At least it seems to show the car isn't dropping off at the big end. Heck, there is so much science to this stuff, I think I enjoy talking about the stats and the math as I do the driving itself. Well, almost. :D

Rich,

My brother dropped about three tenths, maybe more from doing a gosh-honest, keep-the-long-pedal-mashed speed shift. So, no, you're not dreaming. There's more in it if you ragged it, but I have looked at your site, and it's an awful nice car to beat on. graemlins/thumbsup.gif

Originally posted by TH:
Rich,

My brother dropped about three tenths, maybe more from doing a gosh-honest, keep-the-long-pedal-mashed speed shift. So, no, you're not dreaming. There's more in it if you ragged it, but I have looked at your site, and it's an awful nice car to beat on. graemlins/thumbsup.gif I picked up .3 sec by doing that too. Now it crunches a little going into 3rd... smile.gif And I also agree.... I would have trouble beating on a car like yours like that!

Gaining 19mph from the 1/8 to the 1/4 is pretty good, and reflects the higher RPM flavor of the L79 327. For comparison, the more torque-oriented 350 I had in my 69 earlier this year picks up 18mph, from about 80mph in the 1/8 to 97-98 in the 1/4. This equates to ET's in the 13.60 - 13.80 range with a 3.42 gear and auto tranny.

There's a horsepower calculator at www.speedworldmotorplex.com (http://www.speedworldmotorplex.com) try it out.

Hi Rich, The weight i posted is the minimum weight that NHRA allows in a stock class "Malibu SS" 2 DR. H.T. with a 350 H.P. - 327 which they rate at 325 H.P. (pounds per H.P.) 9.74 x 325 H.P.= 3165.5 lbs. This would be a stripped down model with all extras removed, radio, heater, air and other extras. The Malibu two dr. sedan has a factor of 9.58 x 325 = 3113.5 lbs. and the 300 delux is 9.41 x 325 for a weight of 3058.25 pounds. Keep in mind few cars are close to their minimum shipping weight so 3280 lbs. would likely be a more average actual weight figure, and might a little more with a deluxe interior.

I would say you are right at 200rwhp. My buddies Lincoln Mark VIII makes 222rwhp/228rwtq and he runs 14.6 @ 94mph 2.1 60ft with a 3900# racing wieght.
My Thunderbird runs 13.5 @ 101mph 2.00 60ft with only 255rwhp/273rwtq in good air, also 3900# race wieght with driver.

should pick up more MPH in the back half, you need to do jetting/timing loops based on MPH and find out what it REALLY wants.

just because you think its alright, doesnt mean its realising its full potential.

i would be looking for 21-22mph on the back half, quicker cars see 23-26mph on the back half depending on the combo...but i wouldnt expect that from a 14 second car.

You're doing alot with that show car, good stuff, but there is much more left in it.

definetly play with the secondary springs, if it bogs, it might need more squirter.
You may find ET in Secondary spring/squirter loops.

Make little changes and quantify the results.

I think 14.9 is pretty quick for a bone-stock small block chevelle.There's *definitely* more left...check out this link for a pretty impressive Pure Stock 300 Deluxe:

http://www.v8buick.com/showthread.php?t=56081&page=1

Originally posted by Chevy454:
</font><blockquote>quote:</font><hr />I think 14.9 is pretty quick for a bone-stock small block chevelle.There's *definitely* more left...check out this link for a pretty impressive Pure Stock 300 Deluxe:

http://www.v8buick.com/showthread.php?t=56081&page=1 </font>[/QUOTE]Well, I read your link...says the car has a 350 with a TH350 transmission, not a 327 with a 4-spd, has a modified rear suspension, a 3.90 gear, is obviously running slicks and a higher stall converter or something to pull a 1.85 60' time, etc. Rich's car is a complete STOCK restoration, which is quite a bit different from what is allowed in "stock" drag racing. Like I said...14.9 is pretty good for an off-the-showroom car.

You're right, while it's not the hot little L79, it is a 350/300hp 300 Deluxe...as for a modded rear, he does have the Poly bushings & a 3.90 gear. But, I watched this car go 13.40s in Stanton with the rubber bushings and horrendous wheel hop. No slicks and no higher stall converter, either...it's running off the shelf Polyglass tires and the stock converter. This isn't Stock Eliminator, but Pure Stock...basically show cars duking it out. In fact, I watched 'em shoot the pictures for the article in *I believe* Musclecar Enthusist.

I didn't mean for my post to come across as a knock on Rich's car, as his car runs good and he should be commended for even taking it to the track, but just showing what can be done with a little time & patience...so think of my post simply as "motivation"! graemlins/thumbsup.gif

Just a little follow up. I was out for a drive and saw a State Patrol car at a near by but often not used weigh station. I stopped and asked if I could weigh my car on their state certified scale. He said yes.

With a 1/2 tank of gas, nothing in the trunk but the spare and maybe 7-10 pounds of tools and me NOT in the car it was flickering between 3380 and 3400. With my 170 that comes to 3550-3570, a few pounds less than my 3600 quote made earlier but with a full tank of gas I'd be real close to 3600 even with me in the car and a helmet on, etc.

Of course the '69 SS wheels on the car weigh somewhat more than the orignal skinny steel wheels but then I run the SS wheels at the track anyway.

Hi Rich, Back in 1966 i had a 442 Oldsmobile and i always pulled the spare tire out when i raced it. The tire and jack weighed about 60 pounds. The car feels every pound of weight while going down the track and that spare and the full tank of gas will cost you about one tenth in E.T. and probably one MPH in speed. This increase would put your car in the average range for your gears and weight. 3380 lbs. minus the spare would probably get you down to about 3330 pounds which would help quite a bit. My 442 ran 14.54 @ 100.5 MPH with 3.55 gears and a single track rear end and beat most of the cars of that era easily. I once saw a no option '66 chevelle with a 275 H.P. - 327 run 14.20 @ 99 MPH on polyglas street tires but that car bit very well and was well driven. The next time you take your car to the track you might try winding it a little tighter if its still making power. You might also try making sure the tires are up to about 35 pounds as polyglas tires bite better with a little more air in them. My Olds didn't leave very well with the "peg leg" rear end, wish i'd have added a posi-trac and kept the car. P.S.... The olds weighed 3520 bare with about 1/2 tank of gas and i was about 170 pounds for a run weight of 3690 without the spare.

I've tried various shift points. The engine sounds so good and loves to rev hard up to 7000 or so, but at the track I found that shift points at 5800-6000 were what netted the best ETs. It sounds good and feels good at higher RPMs but timeslips don't lie! The power must drop off pretty quickly after 6000 since just shifting at 6200 increased my ETs dramatically. Now if I was willing to put headers on the thing that might change but that just won't happen.

No Polyglass tires on this dude. The original tires are 14x7.75 bias plies. They are very tall and very narrow. Decent straight line traction given their narrow tread width, but they really kill the gear ratio being so tall (nearly 29 inches tall). Besides, for my best times I run 26 inch tall 8 inch wide DOT slicks. I do hope to run the thing in some Pure Stock drags some day so I should run it on the stock tall and narrow tires a few times to see how it will respond. Pure stock rules require running on the same size and style of tire as was available on the car from the factory.

Hi Rich, I don't remember the 7.75 size tires being that tall but a shorter tire would definately give you much improved E.T.s with a motor that is long winded as it doesn't have much bottom end to start with. My 375 H.P. was about a full second slower on asfault when having to leave just above an idle compared to concrete where it could be pulled up to about 3500 and the clutch could be engaged quickly. Quick shifts can be had without "power shifting" with the gas on the floor. Your right about the 6000 RPM producing the best times. Your speed from is right in line with the rest of your timeslip and with the power you have it's only going to gain about 19 MPH between these two points. Thats all my 375 gained when stock. (88 vs. 107) at the quarter with street tires. My sons bad Chevelle only gains 26 MPH the second eight mile on the motor and has roughly 780 HP pushing 3570 pounds total weight.

Those 14x7.75s are roughly an 80 series tire so they are very tall! I had some troubles with them early on that I had to discuss with Coker tire so I had to measure them carefully so I'm pretty certain on the diameter.

Maybe i'll get my Chevelle out of the garage one of these days if i can get one of my engines back from my son and put it in my '67.