??? ABOUT RING & PINION SIZE
 

HOW DO I FIGURE OUT WHAT SIZE RING & PINION I NEED.CAR WEIGH'S 3485 WITH ME IN IT. IM EXPECTING 7000 RPM AT THE END OF THE 1/4 MILE,TURBO 350 TRANS AND PROBALLY 4500 STALL.RICHMOND SAID 4.10,MOSER,STRANGE AND RANDY'S RING & PINION SAID 4.56,IM CONFUSED.I WOULD HATE TO PUT IN ONE GEAR AND FIND OUT I NEED ANOTHER.

Tell me what Mile per hour you want to be at at 7000 in the traps and I can tell you in two min. don't leave out the tire roll out you have or will have

120-125 mph

Jeff, whats your tire size?

27x9x15

4.33 is you your tire roll calculation was 84" this gives 7050 in the traps at 125. Hows that

A 4:56 at 7000 rpm and 27" tire would be 123.36 MPH. I think a 4:56 gear is what I'd run with your combo.

great afr said the head and cam package i bought from them was good to shift at 71-7200 rpm.I was thinking 4.56 which is all i can find for my 8.5 10 bolt,where could I purchase a 4.30 ring and pinion?

How did you come up with such a different answer? Did you figure no slippage in the converter. the moroso scale does not factor this in FYI.

He's running a 4500 stall so the slipage will be minimal. I think the growth of the tire will off set the slipage of the convertor. I'm using a dragmath program thats been very close on actual numbers for me. A 27 in tire actually has 84.82 roll out.