DusterKrazy
Well-Known Member
Does anyone know what kind of hp and weight are required to do high 7's in the 1/8 mile?? Say 7.90's or in that range??
High 7's in the 1/8..how much weight and power??
- Thread starter DusterKrazy
- Start date
-
blownhemi
Well-Known Member
well 7.70 on the 1/8th equals 11.99 on the quarter so you're probably looking at around 450hp in your average A-body
blownhemi
Well-Known Member
what i've posted above is for a normal full weight street combo with 3.5 gears. Less weight and more gears will make it quicker, especially over the eighth
tubtar
Well-Known Member
Very close. 450 h.p. @ 3400 lbs should put you right in the ball park if you don't spin and the car will 60 foot in the 1.8 neighborhood.
blownhemi
Well-Known Member
Yep, I done it with one of my own cars in the past (non-mopar combo but equivalent in weight and power), but right now a friend's street '69 Cuda does pretty much that with a 408 running W2 econo heads with around 450 horse. Runs 11.9 at 115mph with 3.45 gears.
7.90 in the 1/8 is about a 12.40 in 1/4
http://www.wallaceracing.com/8th-quarter-conversion.php
Your ET / MPH computed from your vehicle weight of 3400 pounds and HP of 450 is 11.43 seconds and MPH of 117.22 MPH.
http://www.wallaceracing.com/et-hp-mph.php
Your HP is 352.45 computed from your vehicle weight of 3400 pounds and ET of 12.40 seconds.
http://www.wallaceracing.com/8th-quarter-conversion.php
Your ET / MPH computed from your vehicle weight of 3400 pounds and HP of 450 is 11.43 seconds and MPH of 117.22 MPH.
http://www.wallaceracing.com/et-hp-mph.php
Your HP is 352.45 computed from your vehicle weight of 3400 pounds and ET of 12.40 seconds.
skrews
Well-Known Member
My 360 made 442 HP on the engine dyno. The car runs 7.5-7.6 in the 1/8. Car has 4.56 gear, 4500 stall 8" verter, 28" slicks, and 3400 race weight. 1.58 60' times. DA in the 2500 ballpark.
dirty white boy
50 yr old Juvenal delinquent
how light can i get a 73 duster down to without spending a ton on fiber glass?? looking to run 7.50 class in 8th on a budget!!
75 Duster 360
Well-Known Member
My '75 Duster and I weigh 3225 when we're racing. I have a 360 with 9.5 to 1 compression, stock J-heads with 1.88 intakes, Mopar 284 484 Purple shaft, Crane ductile 1.5 rockers, correct Isky springs, windage tray, Edelbrock Performer RPM, Holley 600 DP, Carter manual fuel pump, Mopar stock electronic distributor with advance slots shortened to give timing at 17 degress idle and 34 degrees total at about 2000 rpm, MSD box and wires, Autolite plugs .045 gap, Flo-Tech 1 5/8 x 3 with 2 1/2" with H-pipe and Flow Masters turned down at rear end, March aluminum crank and water pump pulleys, cheap SuperForce? balancer, K+N filter, Powermaster alternator, 5 blade stock water pump, low gear set 904 with TCI made-to-order $650 converter [bassically 3000-3400 stall, not radical], SS springs with Mopar 3/4 offset shackle set-up allowing 15 x 8 Wheel Vintique rallye wheels with 4 5/8 backspacing, Dutchman axles, Goodyear 10 x 28 slicks, Lakewood 90/10 up front with slant 6 torsion bars and Lakewood 50/50 in the rear, 3.55 gear with Yukon spool, battery in the trunk, Hurst 1/4 gate shifter, A+A manual valve body, Mopar deep pan and trans cooler, added electric cooling fan, bucket seats from my '67 Valiant, Autometer tach straped to steering column, driveshaft loop, stock 10" front drum brakes and 14 x 4 1/2 stock wheels and V-8 K-member all from my '67 Valiant. It has ran as fast as 7.90 at 88 mph when running in cold weather and shallow staging it. That is stalling it to 2500 and shifting it at 5800. I drive mine on the Interstate to the track at 65 mph, so I dont have many of the things that most racers use. If I wanted to, I could makeitgo 7.49 by changing just a few of these many options, such as installing a loose converter, a 4.10 gear, a 700 cfm DP, 9 x 26 rear tires, an electric water pump, removing the alternator, fiberglass hood, aluminum wheels and front runners, running it with a near empty fuel tank instead of completely full, electric fuel pump, bigger cam, 2.02 valves, port heads, run it on alcohol instead of 93 pump gas, etc. The charts in the Mopar chassis and engine books are spot on. If you know the weight of your car, it will tell you what you need parts-wise to run a specific ET. 7.50 is a perfect ET to shoot for. Not too expensive to build and not too hard on the parts.
DusterKrazy
Well-Known Member
2200 is the target weight. Partial tube chassis but still using leaf spring rear. Aluminum floor/trunk floor/firewall.Lexan..etc.. 4.62 gears. '66 Barracuda.
blownhemi
Well-Known Member
That's pretty light and it'll leap out of the hole with those gears, but you'll need all three gears for the 1/8th mile. If you ever run the quarter it'll probably run out of revs.
Is this a real car or just in planning stages at the moment? The reason I ask is there's no real reason to strip it down so much if all you want is mid-high sevens over the 1/8th mile. Although losing that big back glass will probably help and you can probably sell the glass for bucks (I hear they're hard to get) to buy other parts.
Personally I wouldn't be cutting the firewall or floor out of a car like this just to replace it with aluminum. What's you local strip rules? Do you need a cage for those times? Down under we don't need a cage until we run quicker than 7.0 on the 1/8th (10.99 for the 1/4).
Get it down to 2800lb (race weight inc driver) and put a nice 1hp/cube 360ci small block in it with 4.1gears and you'll be in the ballpark.
Edit: I came up with this in my head and then decided to double check using my Mopar Chassis book as recommended by "75 Duster 360" above and it concurs.
2800lbs + 360hp = 117-118mph in the quarter (mid 11s)
3000lbs + 360hp = 114mph (high 11s)
3400lbs + 360hp = 109mph (mid 12s)
All time depend on optimum selection of right gears and converter.
A good rule of thumb for converting 1/4 times to 1/8th times is by multiplying ot dividing by 1.555.
If you car runs 11.99 on the quarter divide by 1.555 and it gives you 7.71 on the 1/8th.
It's not precise but close enough for horse shoes and hand grenades
DusterKrazy
Well-Known Member
That's pretty light and it'll leap out of the hole with those gears, but you'll need all three gears for the 1/8th mile. If you ever run the quarter it'll probably run out of revs.
Is this a real car or just in planning stages at the moment? The reason I ask is there's no real reason to strip it down so much if all you want is mid-high sevens over the 1/8th mile. Although losing that big back glass will probably help and you can probably sell the glass for bucks (I hear they're hard to get) to buy other parts.
Personally I wouldn't be cutting the firewall or floor out of a car like this just to replace it with aluminum. What's you local strip rules? Do you need a cage for those times? Down under we don't need a cage until we run quicker than 7.0 on the 1/8th (10.99 for the 1/4).
Get it down to 2800lb (race weight inc driver) and put a nice 1hp/cube 360ci small block in it with 4.1gears and you'll be in the ballpark.
Edit: I came up with this in my head and then decided to double check using my Mopar Chassis book as recommended by "75 Duster 360" above and it concurs.
2800lbs + 360hp = 117-118mph in the quarter (mid 11s)
3000lbs + 360hp = 114mph (high 11s)
3400lbs + 360hp = 109mph (mid 12s)
All time depend on optimum selection of right gears and converter.
A good rule of thumb for converting 1/4 times to 1/8th times is by multiplying ot dividing by 1.555.
If you car runs 11.99 on the quarter divide by 1.555 and it gives you 7.71 on the 1/8th.
It's not precise but close enough for horse shoes and hand grenades
I have the car and it was gutted years ago. I have most of the parts to make it happen but it is a very slow process. Are the above figures rwhp or hp at the crank?
I will add a cage anyway because of safety. No very fast et is worth my life being ended by a crash with no protection. The local track isn't to strict.
blownhemi
Well-Known Member
The figures are crank horsepower, but real HP numbers, not "my buddy says he had 300hp and my car is faster so I must have 400hp" numbers.
People tend to throw horsepower numbers around like candy these days. So to put it in perspective I'll use one of my old rides as an example. It was an Aussie A-body Charger (3400-3500lb with me in it), it was a real street combo that made only 270rwhp but on the strip it went 12.7 at 107mph running pump fuel, street rubber (not drag radials) and full exhaust. Drove it there, ran the numbers, drove it home. Didn't put a spanner on it.
People tend to throw horsepower numbers around like candy these days. So to put it in perspective I'll use one of my old rides as an example. It was an Aussie A-body Charger (3400-3500lb with me in it), it was a real street combo that made only 270rwhp but on the strip it went 12.7 at 107mph running pump fuel, street rubber (not drag radials) and full exhaust. Drove it there, ran the numbers, drove it home. Didn't put a spanner on it.
moparmanestock
Well-Known Member
You don't need much. My Demon weighs around 3200# with my 150# self in it, I have not weighed it, but is close to that. It is all steel, with factory buckets in front, just no carpet or back seat.
It has a Dana 60 w 4.56 gears, 29.5 in slicks, 904 low gear trans, an ATI 8" converter that stalls at 4600, and MP 380HP 360 LA shortblock with the 508 hyd cam. The heads are stock 2.02 x heads with no work. The compression is about 9:1 and runs on pump premium gas.
On the chassis dyno it puts down 300 HP at 5400, and 314 TQ at 4600. I shift it at 5800 and it runs 7.32 to 7.35 in the 1/8 at 92 MPH.
The previous converter was a street unit that stalled at 2800, the 1/8 mile was 7.80s at 87 MPH. If you run shorter tires, like 27s, you could run 4.10 gears and run your goal.
350fwhp at 3250 should get you there in a good working chassis. Get it to 60'
It doesn't take much to run 7.9's in an A body.
It doesn't take much to run 7.9's in an A body.
my 67 belvedere runs 7.50's to 7.60's at 3550 lbs with me in it, and 60 ft times are 1.61 to 1.65's. motor is 440 with 10.1 compression, rpm performer intake, 1 3/4 in heddman headers, unported 452 iron heads, purple shaft .509 cam, 4.30 gears, and a 27 in. slick. engine only makes around 425 hp according to the Mr. gasket hot rod calculator.
If you really do get it to that weight (which I doubt will happen) then all you would need is a junk yard bone stock engine to achieve your goal....that would be about 1000 lbs lighter than my car...that is a LOT of hacking and lightening.
dugascarman
Member
What kind of motor work did you have done if you don’t mind me asking? Thanks!
skrews
Well-Known Member
Cheap hyper SpeedPro flat tops .050 in the hole, 9.6 comp, .484 MP hyd cam, moderately worked iron heads, RPM intake, 750 Holley, 1.75 headers. Motor ran awesome for what it was. Eventually ran 11.0 in the 1/4 with a .528 solid cam and 5200 converter.
furrystump
Well-Known Member
- Joined
- Nov 13, 2004
- Messages
- 2,103
- Reaction score
- 1,700
He did say it was going to be a slow process!
dugascarman
Member
Ohh ok awesome! I’m building a 72 scamp. It’s going to have no back seat, no steel gas tank, no heater box, etc. Looking to go between mid 7.30s-7.50s. Have everything but the motor figured out. 4300-4500 converter, 904 trans with low first gear set,race clutches, etc. And an 8.75 with 4.30 or 4.56 gears. Just trying to get ideas for the motor. Thanks!
skrews
Well-Known Member
X1000 8" 4500 stall minimum. I'd also recommend 4.56 gears, as 4.30s are notorious for breakage.
Last edited:
-
