Somewhere I lost a second in my 1/4 mile times. I've always run 10.80s and now I'm running 11.80s-12.00s. I’m lost a tenth in my 60ft., a half in the 1/8 and a second in the ¼. I initially thought it was from an E85 conversion I did this year. However when I switched back it still ran the same. Motor runs fine, checked compression and it’s good. I had some work done on the rear end, but doesn’t seem to be binding. The only thing left is the trans. Any ideas would be greatly appreciated. Greg

Its probably your trans or converter going out.

Wow tuff question on where to start check gear ratio maybe someone else is running your gear set

Does the converter still flash the same?

+1 on converter

Check plugs, wires, and dist. cap. Check rotor button. Test fuel pump volume. If all is well, pull front cover and check cam timing. You are losing ET all the way down the track.

Another vote for the converter.

Another vote for the converter.

If it's a flat-tappet cam, I'd check that to make sure you're not losing lobes.

Converter, drop the transmission pan and I bet it looks like a junk metal sale.

Valve springs

Do the EZ stuff first. Make sure the brakes are not dragging. Wierd gremlins breed in the off season.

is the mph the same?

What happens to the converter internally when it starts to fail.
Mick

Rookie question, have you checked electrical stuff? rotor and cap? MI winters gotta be hard on that stuff.

I was once off 7 tenths in the spring and forgot I had backed timing off for cool fall air street driving. was at 29 back to 38 and it went from 12.2 to 11.5.
Just this week I tried throttle stopping to the twelves went back to full throttle and 11.21 [Edited by Moparts - Keep it clean]?? oh timing went from 35 to 40 and 10.82!!
It happens

backing plates on rear axles rotating and binding up the brakes?