Gear selection round about!
09-11-2016, 04:38 AM
#1
Member
Thread Starter
Gear selection round about!
Got a reasonable 408 chev with a Th350 and 10 bolt possi. in an 82 camaro with no A/C and no heaters, hi fi,,and its 100 LB lighter because of all the junk and wireing pulled out
I am running 255 60 15 rear tyres and at 27.4 inches tall they get great traction but my 3.08 rear end is now 2.88:1 and while the engine runs hard to 5500rpm i need to drop the gears to get it Quicker.
i was thinking around 3.25:1 but with the 27 inch big tires i need 3.4 ratio to get it at 3.25 final ratio.
The engine revs fast and its maybe 370 to 410hp at a guess.it runs great.
Its never been to the track,, but with winter over its game on down under possible over the next 3 weeks.
Looking at a 9 inch from Quick performance and i need gear info before i buy
Its real fast but not Quick at getting up there.
The engine has enough torque to pull the car no problems and it will spin the tires into second sometimes as is.
We adjusted the advance so it didnt come on too late and its stopped the whiplash effect that makes you feel like its a rocket but its not.,,its gear selection and i should be right to get onto a better motor
my aim a flat 13 or high 12
I am running 255 60 15 rear tyres and at 27.4 inches tall they get great traction but my 3.08 rear end is now 2.88:1 and while the engine runs hard to 5500rpm i need to drop the gears to get it Quicker.
i was thinking around 3.25:1 but with the 27 inch big tires i need 3.4 ratio to get it at 3.25 final ratio.
The engine revs fast and its maybe 370 to 410hp at a guess.it runs great.
Its never been to the track,, but with winter over its game on down under possible over the next 3 weeks.
Looking at a 9 inch from Quick performance and i need gear info before i buy
Its real fast but not Quick at getting up there.
The engine has enough torque to pull the car no problems and it will spin the tires into second sometimes as is.
We adjusted the advance so it didnt come on too late and its stopped the whiplash effect that makes you feel like its a rocket but its not.,,its gear selection and i should be right to get onto a better motor
my aim a flat 13 or high 12
Last edited by aussiesteve; 09-11-2016 at 05:06 AM. Reason: aditional information needed
09-11-2016, 01:18 PM
#2
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Car: 87 IROC L98
Engine: 588 Alcohol BBC
Transmission: Powerglide
Axle/Gears: Ford 9"/31 spline spool/4.86
Re: Gear selection round about!
With a TH350 and 27.4" tall tires, you're probably better off with 3.73 gears. Depending how high the engine can rev, 4.10's may also be a good option. With a stock 26" tall tire height, I wouldn't recommend anything deeper than 3.73. The taller tire can use the deeper 4.10 gears.
It also all depends on converter stall. Different gear ratios will react differently to different stall speeds. Generally, the more stall speed you have, the deeper the gear should be.
When my car was still basically stock, I had a hopped up 383 in it. Still ran 3.27 gears but I also had a 3800 stall converter on the TH350. Car ran high 11's but diff gears were all wrong. MPH was much higher than regular cars running the same ET.
Now I run 4.86 gears in a 9" with 32" tall tires. 6000 stall converter with a powerglide. I tried some 4.57 gears and the car didn't like them unless I could have dropped the converter stall down to something like 4500.
It also all depends on converter stall. Different gear ratios will react differently to different stall speeds. Generally, the more stall speed you have, the deeper the gear should be.
When my car was still basically stock, I had a hopped up 383 in it. Still ran 3.27 gears but I also had a 3800 stall converter on the TH350. Car ran high 11's but diff gears were all wrong. MPH was much higher than regular cars running the same ET.
Now I run 4.86 gears in a 9" with 32" tall tires. 6000 stall converter with a powerglide. I tried some 4.57 gears and the car didn't like them unless I could have dropped the converter stall down to something like 4500.
09-12-2016, 02:21 AM
#3
Member
Thread Starter
Re: Gear selection round about!
Thanks for the help and i understand the RPM at the 1/4 mile thingy a bit better.
What i am trying to achieve is something i cant afford,,ie,the late 60,s super cars performance like the 396 camaro that could be raced at the local strip and driven on the open road on sundays without sacrificing driveability.
The engine seems to run out of legs at 5500rpm and i aint got it into top gear because i am driving on the street and 5500rpm in second and its dangerous for other people who may walk onto the road or another car pulls in front of me not knowing i am doing over 85mph and hard on the gas.
The fast production cars had like 3.36....3.25... 3.55 and could run a mid 12..some big blocks had 3.7 but would have been terrible on the highway.
I would love to see how it runs with a 3.7 or lower but the engine would be working hard and @ +060 oversize and 1 cylinder with a little corrosion coupled with the junk crank and rods i may be walking home from the track.
I am basicly setting up a fresh car and a dart SHP bottom end (short motor) will be on order in 2017.
please keep in touch,,,
I do have some friends with 1960,s super cars in original trim and they manage mid 12,s with good tyres,,
next wednesday i will attempt my first run under professional conditions and see what happens, i am buying a 9 inch ford rear from Quick performance and they list 3.00,,3.25..3.50 and up to 4.11 4.56.
the car will be put on a dyno tomorrow here in Australia and i will get a good base to start with with HP and Torque figures. I am not worried about numbers but i will need something to go by in gear selection and talking to you guys helps a lot.
The car will be weighed then i will see if its still producing power at 5,500 rpm but i doubt it.
Steve In Sydney Australia
What i am trying to achieve is something i cant afford,,ie,the late 60,s super cars performance like the 396 camaro that could be raced at the local strip and driven on the open road on sundays without sacrificing driveability.
The engine seems to run out of legs at 5500rpm and i aint got it into top gear because i am driving on the street and 5500rpm in second and its dangerous for other people who may walk onto the road or another car pulls in front of me not knowing i am doing over 85mph and hard on the gas.
The fast production cars had like 3.36....3.25... 3.55 and could run a mid 12..some big blocks had 3.7 but would have been terrible on the highway.
I would love to see how it runs with a 3.7 or lower but the engine would be working hard and @ +060 oversize and 1 cylinder with a little corrosion coupled with the junk crank and rods i may be walking home from the track.
I am basicly setting up a fresh car and a dart SHP bottom end (short motor) will be on order in 2017.
please keep in touch,,,
I do have some friends with 1960,s super cars in original trim and they manage mid 12,s with good tyres,,
next wednesday i will attempt my first run under professional conditions and see what happens, i am buying a 9 inch ford rear from Quick performance and they list 3.00,,3.25..3.50 and up to 4.11 4.56.
the car will be put on a dyno tomorrow here in Australia and i will get a good base to start with with HP and Torque figures. I am not worried about numbers but i will need something to go by in gear selection and talking to you guys helps a lot.
The car will be weighed then i will see if its still producing power at 5,500 rpm but i doubt it.
Steve In Sydney Australia