[94cobra69ss396]

Originally Posted by Vettezuki

Assuming 26.1 tires (275/50x15) our transmission and a 6,000rpm shift point/red line, I think we' could take advantage of the taller 3.55 gears.

3.55 = 127mph
3.73 = 121mph

I think we'll have the power to weight to ring out the taller gear and have a faster trap/et.

Can you run a 28 inch tire with 3.73 gears and tell me what mph you show for 6000rpm?

Also know that a Slick will grow as you go sown the track. So if we use a 26 inch slick it will act like a taller tire further down.

[big2bird]

Originally Posted by BRUTAL64

Ok, with my 3:55s I hit 119 in third gear. That's with a 27.9 (P275 15 60) inch on the 3,000 pound vette. So.......................I don't see how your math is right. Math and the real world don't always jive. Just not sure about it is all.

Glenn, what do think about raising the duration/retarding the cam, installing really stiff springs, and raising the redline? (Think Beehives)

[Vettezuki]

Originally Posted by BRUTAL64

Ok, with my 3:55s I hit 119 in third gear. That's with a 27.9 (P275 15 60) inch on the 3,000 pound vette. So.......................I don't see how your math is right. Math and the real world don't always jive. Just not sure about it is all.

The weight is irrelevant, what was your rpm at 119rpm? Your math might be fine. Mine rocks.

Here's a nice accurate graph of a wide ratio top loader, 3.55 gears and 275/50x15 tires. The engine turns the trans turns the axle (not a lop of slop there) turns the tires. Pressure and rotational inertia can have some effect on "real" diameter and effect total final "gearing", but the margin of error would be a couple mph at most I would think.

[BRUTAL64]

Originally Posted by big2bird

Glenn, what do think about raising the duration/retarding the cam, installing really stiff springs, and raising the redline? (Think Beehives)

Ok, when I had my 289 Hipo it would run to 7000+ rpms with the solid lifter factory cam and stock valve springs. The problem we have here is the unknown cam. I think a switch to a known cam with soild lifter/roller will allow the 302 to rev more freely. Beehives are a thought, but cost factor will be an issue.

[big2bird]

If weight is irrelevent, let's make the RX 20,000lbs. Should be good for traction.

[big2bird]

Originally Posted by BRUTAL64

Ok, when I had my 289 Hipo it would run to 7000+ rpms with the solid lifter factory cam and stock valve springs. The problem we have here is the unknown cam. I think a switch to a known cam with soild lifter/roller will allow the 302 to rev more freely. Beehives are a thought, but cost factor will be an issue.

That MUST change . The cam is EVERYTHING.

[Vettezuki]

Originally Posted by big2bird

Glenn, what do think about raising the duration/retarding the cam, installing really stiff springs, and raising the redline? (Think Beehives)

What about blower effeciency? I was under the impression these smaller roots blowers will start to fall on their face from 5,500 - 6,000 rpm.

[BRUTAL64]

Originally Posted by Vettezuki

The weight is irrelevant, what was your rpm at 119rpm? Your math might be fine. Mine rocks.

Here's a nice accurate graph of a wide ratio top loader, 3.55 gears and 275/50x15 tires. The engine turns the trans turns the axle (not a lop of slop there) turns the tires. Pressure and rotational inertia can have some effect on "real" diameter and effect total final "gearing", but the margin of error would be a couple mph at most I would think.

Weight is always a factor

If I remember correctly it was around 6200 to 6500 rpm. I'm just saying a 3.55 gear MIGHT be too tall in the real world. I remember when I was running the 1/4 I was just shifting into forth just before I hit the light with the 3.55s.


Not saying you are wrong , just stating a little real world testing would help here.

[Vettezuki]

Originally Posted by big2bird

If weight is irrelevent, let's make the RX 20,000lbs. Should be good for traction.

Weight is irrelevant for calculating gearing and "potential" speed you silly goose.

[Vettezuki]

Originally Posted by 94cobra69ss396

Can you run a 28 inch tire with 3.73 gears and tell me what mph you show for 6000rpm?

Also know that a Slick will grow as you go sown the track. So if we use a 26 inch slick it will act like a taller tire further down.

I have to go for a few hours, I'll run this later. But yes, the tire changes in diameter is where the real world differences in speed as a function of gearing changes.