Hi
You sound like you have a dynamite setup. Here's my 2 cents:
3.08 are great for top end but poor for bottom end with your setup for
ultimate acceleration. Nice to see that you didn't overcarb your setup by
using twin 450 instead of 650s. Your tunnel ram and cam provide the peak
performance at high rpm probably around 6500 - 7000 rpm. You want to ****ft
up just below that range at the peak of the torque curve.
A higher gear ratio will give you faster 0-60 ft times and you should be
peaking in rpm as you cross the finish line. You also will be able to use
stickier tires. The final gear ratio depends on your tire size and peak
rpm
that you want to cross the finish line with.
Wallace Racing has some great automotive calculators online that can help
you determine what gear ratio you need for your tire size and peak rpm:
http://www.wallaceracing.com/Calculators.htm
For example, I have 255 60R15 tires, from the tire height calculator, it
indicates that they are 27" in height:
http://www.wallaceracing.com/tire-aspect-calc.php
Using the gear ratio calculator for 6500 rpm, 27" tires and 120 mph trap
speed, it comes up with 4:35 gears:
http://www.wallaceracing.com/calcrgr.php
4:11 are pretty steep for the strip/street without an overdrive tranny.
With
a turbo 350 and if its driven on the street, I would check to see what rpm
you would be driving at 60 mph to see if you could live with the higher
rpm.
I read a great book by John Lingenfelter on Modifying SBC engines. His
number one point was what will the engine/car be doing for 90% of the
time.
If it is a street car, you'll be sorry if you modify it for racing and put
it on the street. Gives you a very different perspective.
If you are happy, then leave the 3.08s and keep showing them the tailend
of
the car as you wave good-bye! I have a mildly warmed over 400 sbc with
3.08s in the rear but mine is a show n cruising car.
You can also determine the hp from ET on Wallace racing. It'd be
interesting
to see what it works out too!
Malibu81 wrote:
> I have been in a wheelchair for about 10 years now and i built an 81
> malibu with a 406 sbc, Edelbrock RPM heads, Tunnel Ram w/2-450
> Holleys, full MSD setup, cam is crane 300 dur 510 lift, stall is
> 2800-3200 th350 trans, i am currently running the stock 7.25 inch 10
> bolt w/ a spool and 3.08 gears, i have lakewood lift bars also. it
> gets out of the hole good with the stall and the torque of the 406 but
> my friends all give me crap about my 3.08 gears. dont hear em whining
> about it when i blow their doors off though. what should i do? keep
> taking the crap or go to a diff gear? what will it do to my setup? how
> would the car perform, and what do ya think i am running for hp out of
> it? its a 1972 block w 2 bolt mains.
>
> Thank You All
> Brett B.
--
Eugene Blanchard
http://www.catsasskustoms.com
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