68 chevelle 60 ft issues
12-09-2010, 09:30 AM
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68 chevelle 60 ft issues 
Fresh 468 BBC with stock chevelle rear end housing 4.10 gears, transbreak, turbo 350
At the start of last year we were having ignition issues/valve adjustment issues. It would run 10.90's cutting out down the track with killer 60 fts. We got our issues straightened out and it pulled a 10.70 et. The best 60 ft was 1.49 and it had always torques up like the picture even when it was running 12.30s, but mid season the c clip eliminator bearing broke on the axle which made it slow down to like 11 30s. After replacing the whole c clip set it was STILL running even slower. We went through EVERYTHING including motor and tranny and it all is in tune. My thoughts are that there is still a problem in the rear end. Has qa1 double adjusters in the rear and single adjusters on the front (not sure what brand). I don't understand.. Everything is exactly the same way as when it ran 10. 70. It has to be in the 60 fts because it still feels like it has the same power and mph is still about 120.
Maybe adjustments to the rear shocks to try and make the rear end more stable through take off?
12-09-2010, 10:46 AM
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You don't say what the post-breakage 60' went to. So
hard to say whether this is a rear end / suspension deal
or not. Though I'd say maybe you want more weight
bias to the right tire, from the picture. Bag it, maybe?
hard to say whether this is a rear end / suspension deal
or not. Though I'd say maybe you want more weight
bias to the right tire, from the picture. Bag it, maybe?
12-09-2010, 11:11 AM
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If nothing else I'm going to inspect everything in the rear end this winter, bearings and all. I forgot to mention that this does have a bag in the right side and I keep it around 8 pounds in the bag
12-09-2010, 01:49 PM
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Well if you figure that you have (say) 200#/inch springs and
that rear roll is maybe 4", that's maybe 800# weight bias
(some of it being really the driveshaft torque, but anyway).
The drag bag is, what, maybe 10-12 square inches of top
surface meaning 8PSI is getting you back maybe 100# of
that?
Might want to run a series of pressures with a camcorder
buddy on the job so you can see what happens with more.
Though if you dead hook then it probably isn't mattering;
no tire smoke in the photo?
that rear roll is maybe 4", that's maybe 800# weight bias
(some of it being really the driveshaft torque, but anyway).
The drag bag is, what, maybe 10-12 square inches of top
surface meaning 8PSI is getting you back maybe 100# of
that?
Might want to run a series of pressures with a camcorder
buddy on the job so you can see what happens with more.
Though if you dead hook then it probably isn't mattering;
no tire smoke in the photo?
12-09-2010, 06:22 PM
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Well if you figure that you have (say) 200#/inch springs and
that rear roll is maybe 4", that's maybe 800# weight bias
(some of it being really the driveshaft torque, but anyway).
The drag bag is, what, maybe 10-12 square inches of top
surface meaning 8PSI is getting you back maybe 100# of
that?
Might want to run a series of pressures with a camcorder
buddy on the job so you can see what happens with more.
Though if you dead hook then it probably isn't mattering;
no tire smoke in the photo?
that rear roll is maybe 4", that's maybe 800# weight bias
(some of it being really the driveshaft torque, but anyway).
The drag bag is, what, maybe 10-12 square inches of top
surface meaning 8PSI is getting you back maybe 100# of
that?
Might want to run a series of pressures with a camcorder
buddy on the job so you can see what happens with more.
Though if you dead hook then it probably isn't mattering;
no tire smoke in the photo?
I don't hardly to burn outs at all.. Just enough to where I see a hint of smoke
