You'd need to be making a whole lot of power to begin with to get into speeds where having the tops in or out is going to make a significant difference.

 

wow....not hard to believe.

hell my LG4/700r4 trans am went 143mph(blew up later that night)

but gps sated 143mph on one run and 141 on another

so a 350ci cant run 7 more mph?

 

I was coming home from a party last year at about 11:00pm and decided to floor it down a newly paved road near my house. I got it up to 117mph (in a 45mph zone) before I had to slow down or I would have missed my turn. That was with a stock 305 TPI (not even a hi-po air filter... just a FRAM), stock 700r4, 2.73 gears, and a steel driveshaft. That was the fastest trip home that I ever took (8min instead of 20min), and boy were my brakes hating me that night. I was pretty lucky because as I was taking that turn, a cop pulled up to the intersection. Imagine the insurance rates then! A male teenager with already high insurance rates gets pulled over for doing 72mph over the speed limit while only recieving his drivers license about 7 months before this.

Now I have 3.27 gears (hoping to get 3.42 soon), a 3" aluminum driveshaft and I will hopefully soon have LS1 rear brakes with either LS1 or C4 HD front brakes. I'm hoping to find a legal way to do this next time.

Mike

Oh... my motor and trans still run like a champ. Only reason the rear was swapped is because of the better ratio and disk brakes.

 

Reviving the dead.

I took my car out today to see what it could do, first time since I got the new engine in, vortec crate just under 400hp. 3.42 posi stock converter/700r4 stock shaft etc, I must have hit around 120(no idea actual speed, havent changed speedo gears yet), my t-tops started leaking in air, that was scary, only other time it did that was at the track when I hit 96 in the trap. I dont think I'll ever go that fast again, I think my transmission is fried now, it started bucking and slipping on the ride home

Its sad too, I thought it would be a bit smoother at higher speeds, but boy was it shakey.

 

i was going fast without the t tops on and the whole dash started to shake from all the wind so i slowed down...

 

mine too

 

Really... smoother?? Even though these cars have amazing aerodynamic properties, they weren't designed for these speeds. The 20+ year old rubber seals on your car probably don't help either. lol

Just another reason hardtop cars are better!

 

if my speedo is right..145 mph in OD was like nothing. just open road.
had more to Give.. but did not want to pass more then 4 cars on the right..nexed to the sholder....lol
(have had the car from day 1 so i know the speedo has never been goofy)

and the best 1/4 mile trap speed was 134mph with the NOS.
that was in 3rd. the 700R4 can take it..just use the right Parts.

 

Had a 1986 Z28 LG4 and 1991 Z28 L98 both w/ the 700R4 and both stock.

The '86 with 2.73 and 245/50/16 tires went about 120MPH in 3rd gear at 4400RPM. 4th OD would only take about 1/2 throttle before downshifting back to 3rd.

The '91 with 3.42 gears and the same size tires went about 140MPH in 4th OD at around 3700-3800RPM. Suffered the same downshift to third issue but at about 3/4 throttle. Was no fun running that speed and having to keep the pedal "just right" to avoid the downshift. Instant 5500RPM and loss of speed and it was just murdering the transmission when it happened.

I suppose 150MPH wasn't unreasonable to expect if I had the 4th gear mod done to the '91. Bet it would have been faster w/ the 2.73's and 3rd gear though.

 

well road&track magazine posted an article in october of 86' a shoot out between the l98 iroc, and mustang gt. they were on a closed speedway track. iroc topped out at 149mph and the gt topped out at 148mph. but i didnt think irocs could come with l98's yet in 86 lol. ill look it again so u can correct whatever i said was wrong

 

i hit 135 down the open freeway at night, top of third gear, wouldn't go into 4th, the next day i lost my 3/4 gear,definately wasn't worth the race, all original trans 110,000 miles

 

on a side note:
my 700R4 is not stock..9" cvtr. none lock up.
it will go into any gear you want and any speed...
no need for passing gear (down shift) with the 4.10 gears.
just tap the gas and your GONE!

(WARP FACTER 9 Mr Scott!)
(you go from 4500rpm to 6500 fast!)
Lingenfelter rocks!