Author Topic: direct drive  (Read 416 times)

Offline Lomiler

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  • Your Best Time: 13.5 @1/4 mile dragstrip
  • Your Engine: 1963 Oldsmobile 394 ci
  • Your Track: Pueblo West Motorsports
  • Your Vehicle: fed clone- mid 1950's to 1962- model Chassis Research
  • General Location: Rocky Mountains
direct drive
« on: October 29, 2023, 05:22:43 PM »
 building a Chassis Research dragster clone, time frame trying for is approximately "1960" build, engine a OLDSMOBILE 394cu, 1963, Hilborn fuel injection
 QUESTION,,,, date direct drive used??   What rear axle ratio's used??
 

Offline THE FRENCHTOWN FLYER

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  • Your Best Time: 8.28@168 door; 9.00@147 6-cyl alt; 8.53@160 RED
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  • Your Vehicle: (3) Advanced Chassis altered , The Last Logghe altered, '30 RPU
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Re: direct drive
« Reply #1 on: October 30, 2023, 07:59:07 AM »
most top gas or fuel dragsters went to direct drive ( no trans) by the late 50's. Very few used a transmission in the 60's either. a few tried the torqumaster/auto trans but, they did not work well. By the very late 60s, some were experimenting with 2 speed planetary trans like Don Garlits.
late 50's early 60's... with NO blower with carbs or injectors needed a trans 2 & 3.. high gear



Here's further details:
https://www.jalopyjournal.com/forum/threads/vintage-dragster-transmissions.339287/
« Last Edit: October 30, 2023, 08:02:40 AM by THE FRENCHTOWN FLYER »

Offline JEFF/21C

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Re: direct drive
« Reply #2 on: October 30, 2023, 12:56:17 PM »
do you have a manual bellhousing or scattershield OLDS  had unique blocks and extended over the clutch or torque convertor. you could mount any 3 speed and rotate so shifter levers are on the top for more foot clearance . i started to make an adapter to mount a 4l60e to  371 BECAUSE I didn't like the ones that are available, just too many projects.
GOOD LUCK!

Offline denverflatheader

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Re: direct drive
« Reply #3 on: October 30, 2023, 01:10:21 PM »
For your early 1960s time frame mile, we assume a few things for direct drive.  Not modern drag slicks that circumference grows at higher rpms, so fixed 30 inch diameter slick.  IR injected fuel 394ci Olds full race prepped engine at max 6700 rpm at stripe.  Vehicle weight 1100 lbs.  Elevation 4600 feet.

My overly optimistic guess as follows for rear axle ratios (depends on your race engine build):

         MPH      GEAR RATIO   RPM
straight alky   125      4.29:1      6000
33% nitro      150      3.75:1      6300
75% nitro      175      3.42:1      6700

Offline JEFF/21C

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Re: direct drive
« Reply #4 on: October 31, 2023, 07:44:41 AM »
do you have the complete motor and injection system?

Offline denverflatheader

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Re: direct drive
« Reply #5 on: November 15, 2023, 12:32:11 PM »
Lomiler - I received your message.  Correct, Denver area.  Alan