View Full Version : when to shift ?

06-17-03, 08:47 AM
This past weekend I took the 'vette out to my dad's house for fathers day. All the men were all over it when I popped the hood...I liked hearing comments like "Now this is a Corvette!"
I offered to take my uncle out for a spirited ride to show him what the car can do...(and he was smiling the whole ride). I did a hard acceleration from about 20-65. As I watched the RPM's climb I shifted at around 4k (1st-2nd) & chirped 2nd gear...I also took the car up to 5k 3-4 times and it seems like power was starting to drop off at the higher RPM's...My question is, when is the best time to shift? I thought the LT-1's liked the high RPM's and should be shifted at 5k + under hard acceleration...
I think my carb is a little out of tune also, so that may make the difference...It "whistles"...thats why I had to hood popped, to see if anybody could figure it out...

06-17-03, 09:03 AM
sounds like it's not getting enough fuel. it could be leaning out at high rpm.

06-19-03, 07:43 AM
Good point by Mad-Mic. I have brought my '71 up to 62-6300 RPM plenty of times and it is still pulling strong. My mechanic says I'd have no problem running it up to 7000, but I'm a little too conservative to try.

Robert N
06-19-03, 03:58 PM
Timing may also be an issue.

06-29-03, 10:02 PM
My 72 had a similar problem. Started to wheez over 5k rpm. I brought it to the local 'vette swami who is also a carb guy. He did a dyno tune. The air fuel mix ture had been way to high. It should be about 12-13. Aside from running poorly, bad mixture can also fry a piston.

Now my '72 pulls strong way past 7k (thanks also to headers and MSD) and dnos 310hp (370 #ft torque) at the rear wheels.