I know this is generally a no-no, but....

I currently have the stock rev limiter/shift points, with 275/50/15 555Rs on Weld Pro Stars with 3.73 gears, and it shifts into overdrive at 110mph according to my speedometer.

I'm trapping 104-105 off spray, spraying a 100 shot (soon to be 150). I'm worried that it will shift into overdrive in the quarter mile....is it safe to spray for the last few seconds of the 1/4 mile run?

 

Imo, I wouldnt. I would get your shift points extended to match your gearing and then spray her.

 

Agreed with MEAN LT1

I doubt the clutch pack will handle it. The 3-4 clutches in the 4L60E are notoriously weak, and will probably slip with just the 100 shot, and for sure with the 150. You might get away with it a few times, but I wouldn't chance it.

Now, if your trans is built, then that might be a different story.

 

Spray shuts off at 5700 RPMs, not spraying through the shifts...

My speedo is calibrated and so are the shift points. Is it supposed to shift into overdrive later?

 

Even if you're not sprayin through the shifts, the clutches are still used while in gear I believe.

 

What about an M6? Im completely tacked out in 4th at 112 and now i'm moving to a 150 shot. I think im going to need to go into 5th. Should I just not spray in 5th or will it be fine??

 

I don't think the manual is going to have the same problems the automatic cars will. You'll probably be fine.

 

when i had 3:73 it seems i remember hitting 125-130 before going into OD. i wouldnt be afraid to raise the shift points and rev limits a bit. and then go with a 3:42 gear if you still need more.

i would also not recommend spraying in OD on the m6. you could also get a little taller tire for the track to give you a little more mph.