finish line rpm vs launch

[4spdJohnny]

I am in the process of going from 5.38 to 4.88 gears in a j/sa 70 Sport Sattelite wagon 383 is shifted at 6400 goes thru traps at 7400. Building a trans with a lower first 2.45 to a 2.77. Thoughts keeping the same basic gear multiplication down low and more in power band down track. Does this seem like a move in the right direction or is it normal to "over rev" a stocker that much? It sure seems out of breath last 300 ft. Is that to much of a jump?

[Phillip marvetz]

I made about the same move last year, The car had a better 60ft and ran faster with less RPM at the stripe.

[Mark Yacavone]

What MPH does it run now?

I'd guess it needs a 5.13

[Jeff Lee]

You may find short shifting the 2.77 out of first will help ET.
I would GUESS 5.13's as Mark suggested. Better to have not enough rear gear than too much rear gear.
4speed Johnny needs to put a stick behind that 383! That would be an awesome wagon!

[4spdJohnny]

Thanks Phillip, gives me a little confidence!

Mark, I have a set of 4.88's to try since I'm expirementing didn't wanna pop for new and 5.13 just seem like such a small change?

Jeff, I agree and in fact originally intended on putting 4spd in wagon but now my 16 year old son is racing it and we aren't quite sure if he inherited 4spd gene! rest assured my road runner is still a stick and am building another 70 road runner 440-6pak 4spd combo for stock eliminator. When you say short shift you would shift 1-2 even lower like 5800?

[4spdJohnny]

Sorry Mark, 12.70, 1.69 60 ft 102.8 mph in 3600 ft air with a 25 mile an hour cross wind (I'm sure doesnt effect this aerodynamically superior race car at all!) Brakes were also slightly dragging that day (Strange disc all corners) have since installed adjustable pushrod and springs inbetween pads in calipers seems to have cured. have also switched the car to cal-tracs now so we wil see. Nothing like changing 6 things at once in a combo but I think all right direction also took weight out to move from k to j since those time slips

[Jeff Lee]

Originally Posted by 4spdJohnny

Thanks Phillip, gives me a little confidence!

Mark, I have a set of 4.88's to try since I'm expirementing didn't wanna pop for new and 5.13 just seem like such a small change?

Jeff, I agree and in fact originally intended on putting 4spd in wagon but now my 16 year old son is racing it and we aren't quite sure if he inherited 4spd gene! rest assured my road runner is still a stick and am building another 70 road runner 440-6pak 4spd combo for stock eliminator. When you say short shift you would shift 1-2 even lower like 5800?

Yes, shift 1-2 at a lower RPM than the other gears.
That 16 year old needs to start racing the right way. Give him the 4-speed and put the 2.77 trans in your wife's grocery getter!

[Todd Boyer]

Originally Posted by 4spdJohnny

I am in the process of going from 5.38 to 4.88 gears in a j/sa 70 Sport Sattelite wagon 383 is shifted at 6400 goes thru traps at 7400. Building a trans with a lower first 2.45 to a 2.77. Thoughts keeping the same basic gear multiplication down low and more in power band down track. Does this seem like a move in the right direction or is it normal to "over rev" a stocker that much? It sure seems out of breath last 300 ft. Is that to much of a jump?

Would this be the red Satellite stocker wagon that was on Racing Junk a while back ???

[GTX JOHN]

That would be the one according to what Johnny told me.

[Chris DeGidio]

From experience,I think the 4.88 is the right way to go.We used a 29.5" Firestone/Phoenix in a 70 Road Runner with 383,both 4-speed and 727 were used,4.88 gear was perfect for that combo.I know the wagon is a bit heavier,but with the 2.77 first,I think that will work great.