I have recently upped the power on my stock L-48, and while it didn't seem like much at first, on the autocross course, the results can't be ignored. It's a lot easier and quicker to muscle this car's girth out of the many tight spots on the course, now, resulting in entire seconds being shaved off of my total lap times...and this is with NO practice before the top end rebuild. HOWEVER. I am not without some problems, here.


Problem one might come down to just me the driver. I am now having a hard time getting "smooth" shifts. In other words, no matter how I am trying to feather the throttle when shifting into 2nd or 3rd, at upper RPMs, once the clutch is released, the resulting return of power makes the rear end jerk. Is there a way to minimize this? It is causing me to be a bit spirrely on my may out of faster corners. I have the VBP Perf Plus package, set to 2nd stiffest in front, and 3rd stiffest, in rear. No sway bar in the rear, polly bushings all around. I would like to try to make the car smoother shifting under power, like newer cars are. Is my only real solution to get better at driving it, or to buy a new car, lol?

Problem two, when going around faster, longer turns, where I can get her up to about 75-85mph, it wants to stall. I have never had this issue before, so I'm wondering if it's a combo of the motor running lean at WOT, and the lateral G's pulling on the carb? Any ideas?

 

To clarify, I don't BELIEVE the motor runs lean at WOT...not because of the carb, anyway. It behaves so well on the street, at all RPM ranges, regardless of throttle. Could it be linked to the infamous 76' vette fuel sock issue?

 

Does your Q-Jet have the black plastic insert that goes around the float? I suppose without that you could be exposing your passageways if your fuel-filter is old and your pump is marginal and your float-setting is a little low.

You could always try a pair of richer secondary-rods, as they're a 2-minute changeout, but that will only help if you have enough fuel in the bowl.

 

The more power the more finely you have to match RPM's when shifting, which can sometimes prove more difficult than it sounds.

Don't recall... What weight flywheel? And, Hurst or OEM shifter?

 

OEM shifter, OEM flywheel. I have done nothing to the drivetrain, other than Spicer Ujoints, and general cleaning.

 

Lighter flywheels allow you to more quickly match revs when shifting both up and down, as well as put less impact/stress on your drivetrain. This has nothing to do with the trans being temporarily disengaged and your being able to shove it into gear at will, but where your engine RPM is in relation to the drivetrain when you re-engage. There are those who can't learn to keep up with it, but if you're looking for better performance in the shifting department a 15# 'wheel vs. heavier one should help your driving. While I'm at it, I highly suggest SFI rated flywheel/clutch/plate/scattershield for high-perf and racing applications.

Also, the Hurst Comp+ shifter isn't only superior to the OEM PoS, but by attaching directly to the trans rather than the frame it eliminates driveline movement from the linkage equation.

How well you're able to take advantage of these mods is up to you.

 

I noticed the cornering issue in a Camaro with a Q-jet. It'd stutter when I was cornering fairly hard, especially turning right. I put on a Holley Spreadbore and don't have the problem anymore.