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Discussion Starter #1 (Edited)
How do you guys decide at which RPM you should be shifting at? There's no real manual for it and without a dyno you don't really know where you make peak power. My cam is good from 4000-7500. I shift at 6800-7000 regularly and once in while 7200 but anything over that it sounds like a rod is going to come through the firewall. I have a forged rotating assembly so I know it can take the beating but am I gaining anything by shifting at a higher RPM? Heading to the track this weekend if it doesnt rain and hopefully my signature will change to 11.XX.
 

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Id say try all different rpm to see what makes a difference where....From my experience with my car...the higher I shift it helps my mph but hurts the et....so I shift at 5500.....until I get a torque converter than it all will change.....
 

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Higher doesn't necessarily mean faster. A dyno sheet gives you a good start but since you don't have one, try different shift points and see what your time slip says. Have fun & be safe.
 

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I'd like to know more about your combo. Convertor, gear, trans, and induction. What rpm's are you going through the traps at? Do you have a shift light? If so, just change the rpms 100 at a time to see where it likes it. The cam may be good to 7500, but where is your torque the highest. I'd try shifting it a bit lower than my trap rpm. That's what works best for my dragster. Shifts at 6700 and goes through at 7100. My ,02. Dave
 

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Discussion Starter #5
Dave,
Convertor is a 10" Coan that stalls at 3800 on the transbrake. Trans is a powerglide with 4:10's in the rear. Have a 355 with a 750 mech secondaries DP and and 12:1 with worked over 492 heads that have been angle milled .125. I'm not real sure what my trap rpm is since I've only been to the track a couple times and never really paid attention. Guess @ 6000? I have 28 11.50 15 Mickey Street Et's on the rear. Is there a calculator that would give me a ballpark trap RPM? I do have a shift light and it's set for 6800
 

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The time slip is your best tuning tool..
X2...:yes::yes::yes: & tryin different shift points of course, like Mike & Stroked said.... i was shiftin my 66 7200, and dropped a couple of tenths when i shifted @ around 6500-6700.... hope this helps.... post up ur progress..

LIL JOHN
 

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Discussion Starter #10
What cam is in it?
Its a Crane Solid flat tappet. I also have Crane Gold roller rockers. I was actually thinking about contacting you to see if you could recommend a custom grind for me. I know the heads are holding me back but they've been working good so far for me. They were worked over by competition engineering back in the day.

Duration at 050 inch Lift: 252 int./260 exh.
Advertised Intake Duration: 290
Advertised Exhaust Duration: 298
Intake Valve Lift : 0.536 in.
Exhaust Valve Lift: 0.554 in.
Lobe Separation (degrees): 112
Grind Number: F-290-2
 

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The lobe centers are too wide for what your trying to do. A 108 would be better. The durations are ok, since you have a set of 492's and 12-1 compression.
Dont trash the 492's until you get a flow sheet on them. I had a set of camel hump heads on my '66 Nova back 20 years ago that went 123 N/A. they flowed 245/175 @ .400" and 260/180 @ .500". They came off an old Trans Am 302. We fixed them things about 6 times over a 10 year period :D

That cam has a wide lash range, you can loosen them up .028" hot and see if it makes a difference. Might make the car 60 foot better and recover after the shift better. I would start out with a 6500 rpm shift point first.

If you don't already have one, this would be a good combo for an RPM air gap intake.
 

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Discussion Starter #12 (Edited)
Thanks for the great info. I am running my lash at .026 as it is now. I also put an airgap on this past winter and got rid of the old 64 aluminum vette intake I was running. Also switched over to MSD 6al system with a billet distributor and electric fan and water pump. Hopefully that will get me in the 11's. Thanks again for the info. I will be getting ahold of you this fall to see if you can set me up with the right cam for next year. Fiance put my money on hold until after the wedding in September.
 

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I'd try shifting a bit lower, say around 65-6700 also. Keep it closer in the power range. How much air are you running in the tires. If they're too low, that will slow you down also. In a 69 Chevelle I had, I ran 15lbs in a 9x30 slick with a 9-1 454. It was going 11.50's with a 1.51 60ft time. I have a 10" Coan street convertor in my 65 now, and a 10" Coan convertor for a brake when I put the other engine/trans in. The one for the brake has anti ballooning plates on it. Don't run a stock type convertor on the brake. It WILL balloon. Dave
 

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Discussion Starter #14
I'd try shifting a bit lower, say around 65-6700 also. Keep it closer in the power range. How much air are you running in the tires. If they're too low, that will slow you down also. In a 69 Chevelle I had, I ran 15lbs in a 9x30 slick with a 9-1 454. It was going 11.50's with a 1.51 60ft time. I have a 10" Coan street convertor in my 65 now, and a 10" Coan convertor for a brake when I put the other engine/trans in. The one for the brake has anti ballooning plates on it. Don't run a stock type convertor on the brake. It WILL balloon. Dave
I was running 12 lbs in the rears. It is an anti-balloon convertor.
 

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i would go with what everyone else is saying and just try a couple different shifting points and since its a glide it will be easy to get the idea of what it likes
 
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