C4 Tech/Performance L98 Corvette and LT1 Corvette Technical Info, Internal Engine, External Engine

shift points and rev limits

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Old Jul 18, 2005 | 06:07 PM
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Default shift points and rev limits

where are you guys shifting at. i have a 383 and the chip maker whats to know my WOT shift rpm : i said 5500
rev limiters : i said 6000
should i leave them there or are these good numbers
i have a 91 auto
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Old Jul 18, 2005 | 06:24 PM
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I believe a stock bottom end will take 6k easily.

Will your valve train handle the revs?

When I do heads & cam I plan on shifting at 6k. So maybe 6.5k would be a better limit.
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Old Jul 18, 2005 | 07:05 PM
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At what rpm does your engine make it's most power? Will it rev high enough past that point to make for an effective shift point? I shift my 160,000+ mile stock long blocked Crossfire at 6000 to 6200 rpm.

RACE ON!!!
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Old Jul 19, 2005 | 03:01 PM
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Originally Posted by CFI-EFI
At what rpm does your engine make it's most power? Will it rev high enough past that point to make for an effective shift point? I shift my 160,000+ mile stock long blocked Crossfire at 6000 to 6200 rpm.

RACE ON!!!
That is quite a bit of revs for that CF motor, assuming you are 100% stock and never had the heads off. I never even took my 122,000 mile TPI past 5500 rpms yet, EVEN with my new "stock" 113 heads + LT4 valvesprings/retainers, GM pt no. 12556463.

If so, that's one of the BEST CFs ever made!!
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Old Jul 19, 2005 | 04:08 PM
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My 383 super ram combo liked to shift at 5400. More rpm gave no improvement in 1/4 mile et or mph. Every combo is different. I would start at 4800 and move the shift light chip up 200 rpm at a time till you found the sweet spot. If seat of the pants is the goal, pick the one that feels best
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Old Jul 19, 2005 | 04:31 PM
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Originally Posted by k0rv3tt389
That is quite a bit of revs for that CF motor, assuming you are 100% stock and never had the heads off.

If so, that's one of the BEST CFs ever made!!
The stock intake manifold has been ported and that has helped the breathing, but the long block is not only stock, it has never been disassembled for rebuilding or repairs. The head bolts have never been loosened. It IS a pretty good runner...for a Crossfire, even if it is worn out.

RACE ON!!!
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Old Jul 19, 2005 | 04:45 PM
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I shift my '89 Auto at 5,500 - 5,600 since I installed the TPIS ported Big Mouth base, TPIS ported plenum and the SLP runners...the motor seems like it like to pull up there now. (As opposed to my stock TPI setup that seemed to die out around 4,700 RPM.

I imagine 5,500 would be a good shift point for your 383 and I would certainly think it could easily handle a 6,000 redline, perhaps a good bit more.
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Old Jul 19, 2005 | 06:03 PM
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Originally Posted by CFI-EFI
The stock intake manifold has been ported and that has helped the breathing, but the long block is not only stock, it has never been disassembled for rebuilding or repairs. The head bolts have never been loosened. It IS a pretty good runner...for a Crossfire, even if it is worn out.

RACE ON!!!
So approximately how many passes in the quarter have you made so far ever since ownership? What trans type do you have? Auto? Manual? What's your best ET and trap speed so far? I'm very impressed!
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Old Jul 19, 2005 | 06:20 PM
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Originally Posted by CFI-EFI
At what rpm does your engine make it's most power? Will it rev high enough past that point to make for an effective shift point? I shift my 160,000+ mile stock long blocked Crossfire at 6000 to 6200 rpm.

RACE ON!!!
Damn, that's where my modified LT1 peaks at. I expect that to drop a bit when the stroker bottom end goes in but the torque gain should be killer. That must be one sweet manifold you've got there, my friend!
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Old Jul 19, 2005 | 06:43 PM
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Originally Posted by k0rv3tt389
So approximately how many passes in the quarter have you made so far ever since ownership? What trans type do you have? Auto? Manual? What's your best ET and trap speed so far? I'm very impressed!
Somewhere between 700 and 800 1/4 mile passes. I didn't mess with the car much the first 8 to 10 years I had it. It's a 700R4 with a 2600 rpm stall Vigilanti. No headers, and stock muffler, so far. My best time, factored to sea level, is a 13.861 @ 98.23. I don't know if that was my best mph or not. It was the mph on my quickest ET run. The 60', that run wasn't the best, either.

Originally Posted by Corvette Kid NC
That must be one sweet manifold you've got there, my friend!
I'm glad I didn't keep close track of the amount of time I spent porting it. If I knew, I'd be ashamed to admit it. However, it seems as though it was worth it.

RACE ON!!!
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