RPM

[ron preston]

I've got 3.70 final drive and like to cruise at about 65 this puts me at
about 2800 rpm. I've got prob 30,000 mile since my rebuild 10 yrs ago. (
she sat a lot with only drives around the block.)I have a mild cam,
headers , flowmaster. I'm just curious what should the red line be?
Every once in a while I find it necessary get in the fast lane and in the
bay area that means you better be doing a about 70-75!.
Thanks
Ron preston
San Jose

 

[Jim Hupy]

5000 for short periods. 4500 all day long.
Jim Hupy
Salem, Or
78 GMC ROYALE 403

> I've got 3.70 final drive and like to cruise at about 65 this puts me at
> about 2800 rpm. I've got prob 30,000 mile since my rebuild 10 yrs ago. (
> she sat a lot with only drives around the block.)I have a mild cam,
> headers , flowmaster. I'm just curious what should the red line be?
> Every once in a while I find it necessary get in the fast lane and in the
> bay area that means you better be doing a about 70-75!.
> Thanks
> Ron preston
> San Jose
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> Unsubscribe or Change List Options:
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[jim kanomata1]

You can go 4500 RPM
People that have never raced a stock 455 will say I'm crazy

Sent from my iPhone

>
> I've got 3.70 final drive and like to cruise at about 65 this puts me at
> about 2800 rpm. I've got prob 30,000 mile since my rebuild 10 yrs ago. (
> she sat a lot with only drives around the block.)I have a mild cam,
> headers , flowmaster. I'm just curious what should the red line be?
> Every once in a while I find it necessary get in the fast lane and in the
> bay area that means you better be doing a about 70-75!.
> Thanks
> Ron preston
> San Jose
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org

 

[Bob Dunahugh]

Jim Hupy got it. With a 3:70 you'll never get there. 403 or 455. The 403 has a 1/4" large bore then the 455. ( 403 at 4.351", and the 455 at 4.126". Thus the 403 bore is to the point that there is no water passages between the cylinders. The 403 has a stroke of 3.385". And that is very close to a 350 Olds at 3.348". The 455 is at 4.25". The cam, distributor, and carb in any engine are the hart of were an engine puts out it's peak torque. And we drive torque. Not HP. Both engines put out of their peak torque under 3000 RPM at full throttle. But the peak torque rating IS NOT a red line. Red line is above 5000 for the 455. And the 403 is even higher due to it's shorter stroke. As a note. Most owners that have the 403. Have noted that the 403 pulls best in the 3000 to 3300 RPM range. Bob Dunahugh