1974 4 Speed Top Speed?
#1
Melting Slicks
Thread Starter
1974 4 Speed Top Speed?
Has anyone actually driven one of these things flat out in stock condition? The speedo goes to 160 but I would think it won't do anywhere near that, especially without overdrive. I sometimes wonder what mine would do. I got up to about 80 once but value my driver's license too much and slowed down real quick. I estimate I have about a 3:50 rear gear by turning the rear wheel and counting drive shaft revolutions. I also have headers, and an Edelbrock carb and intake, which I guess may have added 50 H.P., or is that wishfull thinking?
#2
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#4
Race Director
5500rpm, 1:1 transmission ratio, 27" tire...rear gear and mph below
2.73 162mph
3.08 143
3.36 131
3.55 124
3.73 118
4.11 107
FWIW I've redlined mine in 4th w/ 3.55's. I also redlined my C5 w/ 2.73's...
2.73 162mph
3.08 143
3.36 131
3.55 124
3.73 118
4.11 107
FWIW I've redlined mine in 4th w/ 3.55's. I also redlined my C5 w/ 2.73's...
Last edited by jim2527; 02-10-2016 at 03:43 PM.
#7
Le Mans Master
Your numbers are right on....Even with the anemic stock engines in the 70's, the 4 speeds cars and 3.70 gears like my 78 topped out (documented in the car magazines) at 5,500 RPM (78 L-82) at 119 mph...130 mph at 6,000 RPM. A stock L-82 if it had a 3.08 gear with the 4 speed (which it did not) would hit 150 MPH at 6,000 RPM...might take a while to get there, but it would do it.....My 2010 totally stock C6Z06 given a long enough flat road will top out at 198 MPH (documented as well)..now that is serious top end.....
Last edited by jb78L-82; 02-10-2016 at 06:58 PM.
#8
Drifting
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Has anyone actually driven one of these things flat out in stock condition? The speedo goes to 160 but I would think it won't do anywhere near that, especially without overdrive. I sometimes wonder what mine would do. I got up to about 80 once but value my driver's license too much and slowed down real quick. I estimate I have about a 3:50 rear gear by turning the rear wheel and counting drive shaft revolutions. I also have headers, and an Edelbrock carb and intake, which I guess may have added 50 H.P., or is that wishfull thinking?
Ed
#9
Drifting
I think I had my first Corvette, a 77 L48 auto, to about 105 mph. It would have gone more, but I ran out of straight road. I was only 19 at the time, the car was a bit of a clunker, and I didn't trust it.
My 1970 L46 4-speed I'm certain would go much more than that, but would be limited by both a 3.70 axle and my fears of damaging the original engine.
My father had about 20 different Corvettes over his life, and he told me several times that the fastest was a red 1969 427 435hp coupe that he bought new in Halifax, Nova Scotia. He was a bit of an animal, and said that he had the thing at 150 mph on the way home to New Brunswick. He said the nose was so light at that speed that he never tried it again.
I would love to drive a C6 Z06. What a machine.
My 1970 L46 4-speed I'm certain would go much more than that, but would be limited by both a 3.70 axle and my fears of damaging the original engine.
My father had about 20 different Corvettes over his life, and he told me several times that the fastest was a red 1969 427 435hp coupe that he bought new in Halifax, Nova Scotia. He was a bit of an animal, and said that he had the thing at 150 mph on the way home to New Brunswick. He said the nose was so light at that speed that he never tried it again.
I would love to drive a C6 Z06. What a machine.
Last edited by Brcmpbl; 02-10-2016 at 11:11 PM.
#10
Race Director
I saw an "indicated" 125 mph on my 74 once, lapping Pocono Speedway. This was around 1980 at an SCCA Nationals race. During the lunch break, they'd bring all of the cars from the infield car corrals out onto the speedway for "parade" laps. My 74 was an L-82, 4 speed with 3.70 gears, and was stock except for removal of the A.I.R. system.
#11
Le Mans Master
I purchased a new Corvette in 1977. L-48, automatic and 3:08 gears. It would top out at about 125. A good friend also had a similar '77 and had the same results. We later both removed our "cats" and installed "test-pipes" to see if it would make a difference. Both of us could then get to 130 with no other changes.
Of course we then reinstalled our "cats" like the good little environmentalists we were... er, are!
Good luck... GUSTO
Of course we then reinstalled our "cats" like the good little environmentalists we were... er, are!
Good luck... GUSTO
#12
Drifting
Makes me wonder what my 80 top end would be with a 385 stroker engine, T56 6 speed, 3.70 rear, lowered front and rear with 25.55" tall 275/40 ZR17 tires, and weighing 3180 lbs. No good places around me to try.
#13
Le Mans Master
650 NET HP @ 6,400 RPM
650 ftlbs NET Torque @3,400 RPM
Weight 3546 lbs
Final Drive-3.42:1
4th gear 1:1 150 MPH @ 6,500 RPM
5th .81:1 186 MPH @ 6,500 RPM
6th .67:1 186 MPH @ 5,400 RPM
7th .45:1 186 MPH @ 3,625 RPM
Even with Massive HP, the C7Z06 cannot get more MPH after 5th overdrive. Probably could get more MPH in 6th but it would take a massive increase in Net HP over the 650 it has already...say 800 NET HP
Lots of assumptions here but here we go:
If you had the 3.70 gear with a 27 inch tire (which you do not), your top speed in 4th 1:1 would be about 130 MPH at 6,000 RPM. Since you have a shorter tire 25.55 inches, your top speed at 6,000 RPM would be substantially less since a shorter tire acts like a higher numerical rear gear..say 4.11's. Let's say with your tire in 4th gear you would top out at 120mph in 4th @ 6,000 RPM. The C7Z06 with 650 NET HP!!! overcomes any of the overdrive gears to hit 186 MPH track limited by the aerodynamic add ons that actually do add down force on this car. Not knowing the HP (mostly like in Gross Ratings) of your 385, even if it has 500 GROSS HP, that would roughly equate to 425 NET HP which is 225 NET HP less than the Z06 but you have a 300 lbs weight advantage. The weight advantage is more beneficial to acceleration than top speed. The 6th overdrive will not add anything to the top speed just the 5th overdrive. Depending on the overdrive ratio and assuming 425 NET HP can hit redline in 5 th AND considering the tremendous aero drag and lift from the 80 body, I would guess the top speed is somewhere between 140-145 MPH.
Last edited by jb78L-82; 02-11-2016 at 01:34 PM.
#14
Safety Car
This will tell you what your speed would be at a given rpm but it don't account for converter slippage. Two engines built differently with the same rear gear, transmission gear ratio, tire diameter and converter slippage will will turn the the same mph at any given rpm. Obviously the engine with the higher redline will turn a higher mph so long as the engine has enough torque to reach the redline in either the 1 to 1 final or the overdrive ratio such as .75 to 1. Things such as weight and horse power play into how long it takes to reach the speed and weather or not the engine makes enough torque at that rpm to propel the car to that speed.
http://www.wallaceracing.com/calc-gear-tire-rpm-mph.php
http://www.wallaceracing.com/calc-gear-tire-rpm-mph.php
#15
Drifting
My car has a horrible tendency to oversteer and Im still trying to figure out the alignment issues thats causing that....
So, when my 454 gets over 90 MPH (which I get to REAL quick) it gets very scary. Also, running generic sidepipes makes it sound like its going to blow up at those RPM's.
So, when my 454 gets over 90 MPH (which I get to REAL quick) it gets very scary. Also, running generic sidepipes makes it sound like its going to blow up at those RPM's.
#16
Melting Slicks
My car has a horrible tendency to oversteer and Im still trying to figure out the alignment issues thats causing that....
So, when my 454 gets over 90 MPH (which I get to REAL quick) it gets very scary. Also, running generic sidepipes makes it sound like its going to blow up at those RPM's.
So, when my 454 gets over 90 MPH (which I get to REAL quick) it gets very scary. Also, running generic sidepipes makes it sound like its going to blow up at those RPM's.
#17
Race Director
I went 186mph @7000RPM with 600+HP, 3.08 rear end and 1:1 in 4th.......
..........on an chassis dyno
..........on an chassis dyno
#18
Drifting
Maybe I used the wrong term. The car 'wanders'. It doesnt like to track straight. If I take my eye off the wheel for one second (to maybe look at my watch) Im damn near in the next lane. ALL suspension components have less than 1K miles on them. The alignment shop I used was somewhat familiar with Corvettes but only had access to stock measurments. I think it needs more negative camber, but Im no expert and sadly, nobody in my neck of the woods is willing to do an alignment on an old Corvette.
#19
Drifting
Just consider your decade old tires before you go on any bonzai runs please.
#20
Drifting
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I think I had my first Corvette, a 77 L48 auto, to about 105 mph. It would have gone more, but I ran out of straight road. I was only 19 at the time, the car was a bit of a clunker, and I didn't trust it.
My 1970 L46 4-speed I'm certain would go much more than that, but would be limited by both a 3.70 axle and my fears of damaging the original engine.
My father had about 20 different Corvettes over his life, and he told me several times that the fastest was a red 1969 427 435hp coupe that he bought new in Halifax, Nova Scotia. He was a bit of an animal, and said that he had the thing at 150 mph on the way home to New Brunswick. He said the nose was so light at that speed that he never tried it again.
I would love to drive a C6 Z06. What a machine.
My 1970 L46 4-speed I'm certain would go much more than that, but would be limited by both a 3.70 axle and my fears of damaging the original engine.
My father had about 20 different Corvettes over his life, and he told me several times that the fastest was a red 1969 427 435hp coupe that he bought new in Halifax, Nova Scotia. He was a bit of an animal, and said that he had the thing at 150 mph on the way home to New Brunswick. He said the nose was so light at that speed that he never tried it again.
I would love to drive a C6 Z06. What a machine.