terrible quarter mile time

[jahen65]

the first time i took my 65 mustang out to the track it did 16.3 due to no traction on cheap nitto 225/60/15 so i invested in bf goodrich street legal slicks, now i have ran four times and my car hooks off the line but it lost performance greatly. my car doesnt downshift hard like it used to could this be due to the bigger heavier tires? also i upgraded from 195/60 r15 to 225 60 15 in front.

 

[jahen65]

also

by the way now the best run with these better tires are a terrible 16.8 not that my first runs were any better.

 

[ForceFed70]

Hmmm..

So is your car slower or what's your complaint? How much slower? Why would your car be downshifting in a drag race?

16 second times in a 65 with a 289 doesn't surprise me at all...

 

[ForceFed70]

by the way now the best run with these better tires are a terrible 16.8 not that my first runs were any better.

ahh..OK, it is slower.

Can't tell you why. Maybe the car is bogging off the line because of the better traction? What are your 60ft times? How fast is the car moving at the end of the 1/4?

Have you done any engine work? Like I said.. I would expect 16second runs from a near stock 65.

 

[jahen65]

yes my car is slower it doesnt pick up speed as it used to, i meant downshifting on the street when i step on it. actually the engine is built descent with 270 horses at crank. (estimate)

 

[mach1one]

If you're running slicks + auto w/o a high stall, you'll bog like crazy off the line. That's why there's higher stall converters.

Plus you added weight in the front with the bigger tires.

And 16 sec sounds reasonable out of a 30 y.o basically stock classic.

 

[Billgear]

What is your trap speed?