Gear vs rpm

[Fox_hunter42]

We run a 3400# street stock. Metric chasis, 383, holley 500 2 bbl, headers, hoosier a40 tires. 1/3 mile semi banked dirt. trans in high gear, 650 rear gear. What should this be turning for rpm. I know all about everything that factors into it, just a ball park

[SRXSRULE]

7500-8000+ depends on on how good the piece is. I had a nice 10.5-1 360 with cast iron 76cc heads, holley 500 2 bbl, with headers in a 3200lb metric car and with a 650 gear on a high bank 1/4 mile tack and we had a 7800rpm chip rule and it hit the chip every night. without the chip in it would turn 8000-8100. Eric

[Fox_hunter42]

sounds like you were spinning, no way will that set up turn 8000 here. Im hoping to get to 6800-7000

[SRXSRULE]

Not spinning at all. That example is a strong IMCA stock car with the 360 spec engine option. Several guys run that gear ratio with that engine option and all are turning 7800 rpm.

I'll give you another example.... IMCA hobby stock. 9:1 360 with 76cc heads and cast iron exhaust manifolds and a crappy 2bbl rochester carb, 84" roll out DOT tire. 650 gear will turn 68-6900 on that same 1/4 mile track.

on a 1/3 mile track with a 383, 500 carb, and headers with a 650 gear.... I would be shocked if it didnt turn atleast 7500. Post back what the results are :)

[Dirtman29]

We run a 3400# street stock. Metric chasis, 383, holley 500 2 bbl, headers, hoosier a40 tires. 1/3 mile semi banked dirt. trans in high gear, 650 rear gear. What should this be turning for rpm. I know all about everything that factors into it, just a ball park

Are you running Kankakee? I ran a 650 gear there years ago in my 3280# metric chassis with a 406 engine, same carb, same hoosier tires and turned 65-6700 RPMs.

[fastford]

7500-8000+ depends on on how good the piece is. I had a nice 10.5-1 360 with cast iron 76cc heads, holley 500 2 bbl, with headers in a 3200lb metric car and with a 650 gear on a high bank 1/4 mile tack and we had a 7800rpm chip rule and it hit the chip every night. without the chip in it would turn 8000-8100. Eric

im just curious , what 2 brl holley are you running to make usable hp at 8000 rpms ?

[Fox_hunter42]

Dirtman, yes Kankakee. I would believe the 65-6700. I would be happy with that. We ran 6300 in heat and 6000 in feature last week. BUT we found 2 bad plug wires, and possibly a leaking intake gasket. Both corrected, hope for better this week

[stockcar5]

There are ZERO IMCA stockcars turning 7800rpm.
A 383 with a 2bbl will like about 7000 max. Anything over that you are making no power and just making noise.

[Racer96m]

I ran a 650 gear at K3 and turned 7K. Won a lot of races there with that combo.

Dave

[SRXSRULE]

"There are ZERO IMCA stockcars turning 7800rpm.
A 383 with a 2bbl will like about 7000 max. Anything over that you are making no power and just making noise."

Stock car5....... thank you for posting that. Not sure why I said 7800 rpm rule for the stock cars, 7800 is the mod rule.
7400 is the stock car rpm rule.
The first year IMCA had the 360/500cfm option there wasnt an RPM rule and several guys were pushing them to 8,000rpm. Eric