Just curious to know what everyone else with the stock H/C/I shifts at in their 5.0? After making some passes at the local 1/8 a few weeks ago, I wondered if maybe I was shifting too soon/too late? I usually slam into the next gear at around 5,500, but I've heard our cam runs out of juice at around 4,800 or 5,000 rpms?
Stock cam - shift points?
- Thread starter 302GTS
- Start date
I used to shift mine around 5,200-5,400RPM on the stock Tach. You ideally want it a few hundred RPM above peek in order to drop you just into the beginning of the sweet spot of you power band when you select the following gear. Shift right at peek and you'll likely find yourself lollygagging a little until the engine finds that sweet spot again.
blksn955.o
Founding Member
Myself and several buddies that have had 5.0 cars starting in stock H/C/I combos always have gotten the best results shifting at 5k. By the time you factor in reaction time from seeing 5k and actually changing gears (even if you power shift) the engine will be at the 5,300-5,500 mark.
Zero Signal
Active Member
There is a method of calculating the shift point given your torque curve and tranny ratios. You shift where the tractive effort of the current gear crosses that of the next gear. I used to have a spreadsheet I made that did that. With stock numbers, the shift points were different for each gear, but pretty much all around 5200 rpm. So given reaction time, you could start your shift at 5k and pretty much be on the money.
Black95GTS
Active Member
I shifted mine stock at 5100-5200 (stock tach) before I retarded the camshaft 4 degrees, at which point I shifted at 5500-5600.
Your stock valves will start to float around 5500 typically.
Adam
Your stock valves will start to float around 5500 typically.
Adam
As you can see by the replies above ...........
Most say to shift lower than you have been shifting
I would say that is good advice
but
If you got the stock tach
They are known to read a bit high
A sure fire way is to keep accurate records of your runs
You are keeping records now ... aren't you
Anyway
Just start shifting at something like 4800 and add a bit more rpm
to each pass and your time slips will tell you where the sweet
spot is gonna be
That way ... Even if your tach is a good bit off ... It won't matter
Grady
Most say to shift lower than you have been shifting
I would say that is good advice
but
If you got the stock tach
They are known to read a bit high
A sure fire way is to keep accurate records of your runs
You are keeping records now ... aren't you
Anyway
Just start shifting at something like 4800 and add a bit more rpm
to each pass and your time slips will tell you where the sweet
spot is gonna be
That way ... Even if your tach is a good bit off ... It won't matter
Grady
xr8d302
I bought a 27" monitor to compensate for my lack o
Ah it's good to see Grady
Spreading his wealth of knowledge
And making it seem poetic
Like a really badly formatted Haiku
This is why I keep coming back :SNSign:
Spreading his wealth of knowledge
And making it seem poetic
Like a really badly formatted Haiku
This is why I keep coming back :SNSign:
Yessir, I've got every timeslip from every pass I've made, and the main thing I find from each one is that a driver mod is necessary!As you can see by the replies above ...........
Most say to shift lower than you have been shifting
I would say that is good advice
but
If you got the stock tach
They are known to read a bit high
A sure fire way is to keep accurate records of your runs
You are keeping records now ... aren't you
Anyway
Just start shifting at something like 4800 and add a bit more rpm
to each pass and your time slips will tell you where the sweet
spot is gonna be
That way ... Even if your tach is a good bit off ... It won't matter
Grady
I'm still working on finding that sweet spot for the launch, and next time I go out I'll try your technique of starting at 4,800 and advancing until I reach the best time. Thanks man. 
Black Stampede
Founding Member
Yessir, I've got every timeslip from every pass I've made, and the main thing I find from each one is that a driver mod is necessary!
I like what you have said here
I confess it has been years since I slipped down the Ole 1320
but
I did make many many passes in many different cars
I was always amazed how it took a while to get all the simple things
like shift rpm launch, coolant temps, tire pressure, etc all dialed in
after you changed cars or made a major change
For sure ... stuff like that that can shave a good bit of time off the et
I used to write all that data in a spiral notebook
Yes ... like you said ... practice can be one of the best driver mods
Grady
Perfect practice makes perfect!I like what you have said here
I confess it has been years since I slipped down the Ole 1320
but
I did make many many passes in many different cars
I was always amazed how it took a while to get all the simple things
like shift rpm launch, coolant temps, tire pressure, etc all dialed in
after you changed cars or made a major change
For sure ... stuff like that that can shave a good bit of time off the et
I used to write all that data in a spiral notebook
Yes ... like you said ... practice can be one of the best driver mods
Grady
My first time at the strip, I launched at 4 grand like I would on a normal road, and instead of spinning slightly then hooking and going, my rear end went sliding down the strip at an angle all through first. I tried feathering the gas a bit, and all it wanted to do was spin. 
So far I'm finding around 3,200 to be my best launch rpm, with 15 psi in the tires. I also really need to work on shifting quicker. I was powershifting, but after grinding and missing too much, I'm going to work on just shifting much quicker than normal without having to powershift (AKA I'm too cheap to feel like replacing tranny parts ).
Husky44
10 Year Member
blksn955.o
Founding Member
As far as launching goes...
On street tires I found 24-28lbs (depending on conditions) and leaving at 2k rpm gave me the best 60ft. Avg. around 2.0-2.1 with a best of low 1.9. Really that is about as good as it gets on street radials. You do not get a big plus in lower air pres. in radial tires as the sidewall just does not have the sidewall give/wrinkle or compound to take advantage of the low PSI.
DR- I am still learning those myself not enough seat time....but I have had some very good tips/pointers just need to get good at implementing them.
On street tires I found 24-28lbs (depending on conditions) and leaving at 2k rpm gave me the best 60ft. Avg. around 2.0-2.1 with a best of low 1.9. Really that is about as good as it gets on street radials. You do not get a big plus in lower air pres. in radial tires as the sidewall just does not have the sidewall give/wrinkle or compound to take advantage of the low PSI.
DR- I am still learning those myself not enough seat time....but I have had some very good tips/pointers just need to get good at implementing them.
I've got street tires, but they're verrrrry soft compound. On the street I can dump it at 3500-4000 and it'll spin for a split second but hook and go after. I got a 2.0 60' leaving at around 2,800-3,000 at about 15 psi.
