What did you do to your Monte Carlo today?

[Marks71]

Finally swapped out the leaky rear shocks for the Bilsteins. Major difference. The ride is not overly firm at all. Went with grade 8 hardware also. By the way Dennis, I made sure the nuts are on top.

[SPLATT71MC]

Got my custom order wheels just waiting to get them mounted and balanced. Will post pics when I get them back.

[Blackhawk]

Got it put back together finally. Ignore the handprints, but above them you can see some of the color poking out. 

[Scott S.]

I'm sure there'll be a few more before your finished.

[SPLATT71MC]

Got my wheels and tires mounted and balanced today.

 

[Marks71]

It’s hard to beat the AR TorqeThrust stile wheel. 18s?

[SPLATT71MC]

12 hours ago, Marks71 said:

It’s hard to beat the AR TorqeThrust stile wheel. 18s?

18x9.5

[Marks71]

Can’t wait to see them on the car.

[Michael Boyte]

On 10/3/2024 at 11:21 PM, SPLATT71MC said:

Got my wheels and tires mounted and balanced today.

 

Those wheels and tires are going to look fantastic, can't wait to see them on your car !!

[420ponies]

That's what I call "Grip" They look nice!🙂

[cny first gen 71]

Took mine out today for a little ride, of course I stopped for ice cream and just cruised around for a bit. Was a little cool mid 60s but not to awful.  Had to winterize the camper today too. Season is over for us now just gotta get it put up in it's winter resting place pull batteries and put wheel covers on.

[madmatt9471]

I installed the proper "driven" gear in my Monte to correct the speedometer. It was off by approximately 5 MPH (reading too fast)

Drive gear is purple (10 teeth) and the driven gear was White (or natural with 18 teeth), I switched it to the Red driven gear (with 21 teeth), which slowed down the speedometer and get the proper MPH reading, and all is good now.

Of course it puked out right around 32oz of transmission fluid that I measured and replaced. Easy fix!

Thanks,Matt 

[riverdogs00]

On 9/10/2024 at 12:56 PM, John S said:

My tachometer must be way off. I have a Muncie four-speed, 3.31 gears but still the final drive ratio is 1:1. At 70 mph I’m 3300-3400 RPM. I’m going to have to get another tachometer, temporarily hook it up and see what the difference is. Thanks for posting that. 

Group, did we ever come to a resolution on this?  On my 70 SS I have the TH400 and 3.31's. I just installed 15x8 rallys and 275/60/15's (28"tall) and then downloaded a GPS speedo on my phone.  My speedo at 65 is about a 1 mph low is all (I changed speedo adapter gears before when I went from 2.56s to the 3.31s so now it is more correct ha) and the RPM on the factory tach was 3000.   That was the impetus of going to a larger tire as it was closer to 3200/3300 before with 26" tall tires.   when I use the online calculators, it says my RPM should be in the 2550/2600 range at 65.

[DragCat]

25 minutes ago, riverdogs00 said:

  when I use the online calculators, it says my RPM should be in the 2550/2600 range at 65.

Last 2 posts got me thinking, can you post a link for the online calculators for RPM? I'd like to verify my Tach.

I know after my upgrades my speedo was 15MPH off, (thanks to the sheriffs office and their solar powered digital speed signs 🤣) But I never cared since I usually only go 1/8 mile at a time.

I can use my Dragy (GPS) for speed but should and would like to verify the tach.

 

 

[420ponies]

Well guys, I just fired up my 427 BBC for the 1st time, and it was a great day ! ! Just a few leaks, nothing I can't fix. The Wife was behind the wheel, (on jackstands ) and we had a great  20 minutes of breaking in the rings, and watching all the gauges work in the interior of the Monte !  After we adjusted the idle and everything was good. It's been a long road with all the additions I have added with the rebuild of the drive train to make this possible.  Can't thank all of help of the members here on the forum .Thank you all.🙂🙂

 

 

 

[riverdogs00]

4 minutes ago, DragCat said:

Last 2 posts got me thinking, can you post a link for the online calculators for RPM? I'd like to verify my Tach.

I know after my upgrades my speedo was 15MPH off, (thanks to the sheriffs office and their solar powered digital speed signs 🤣) But I never cared since I usually only go 1/8 mile at a time.

I can use my Dragy (GPS) for speed but should and would like to verify the tach.

 

 

There are multiple out there.  here are a few     https://spicerparts.com/calculators/engine-rpm-calculator

https://www.blocklayer.com/rpm-gear     https://purperformance.com/p-29669-rpm-calculator.html   https://www.randysworldwide.com/calculators/transmission-ratio-rpm

 

[madmatt9471]

Here's one that I use and really like: 

https://www.crawlpedia.com/rpm_gear_calculator.htm

Thanks, Matt 

[John S]

1 hour ago, riverdogs00 said:

Group, did we ever come to a resolution on this?  On my 70 SS I have the TH400 and 3.31's. I just installed 15x8 rallys and 275/60/15's (28"tall) and then downloaded a GPS speedo on my phone.  My speedo at 65 is about a 1 mph low is all (I changed speedo adapter gears before when I went from 2.56s to the 3.31s so now it is more correct ha) and the RPM on the factory tach was 3000.   That was the impetus of going to a larger tire as it was closer to 3200/3300 before with 26" tall tires.   when I use the online calculators, it says my RPM should be in the 2550/2600 range at 65.

Called Pertronix they told me that could be a problem with the tachometer off. They suggested buying a 10K ohm 1/2 watt resistor and putting it in the tachometer line.

[riverdogs00]

13 minutes ago, John S said:

Called Pertronix they told me that could be a problem with the tachometer off. They suggested buying a 10K ohm 1/2 watt resistor and putting it in the tachometer line.

I probably should have mentioned that I'm running a HEI in it.  I dont know if that changes things or not   

[John S]

10 minutes ago, riverdogs00 said:

I probably should have mentioned that I'm running a HEI in it.  I dont know if that changes things or not   

I don’t know those resistors are very inexpensive. I’m going to connect one to the end of the tachometer wire and put the other end on the coil and see if it makes a difference. Simple to try. It doesn’t work. It doesn’t work.

[riverdogs00]

29 minutes ago, John S said:

I don’t know those resistors are very inexpensive. I’m going to connect one to the end of the tachometer wire and put the other end on the coil and see if it makes a difference. Simple to try. It doesn’t work. It doesn’t work.

will wait for your report 

[Scott S.]

Hey Michael,

One of Holley's affiliate companies (Classic Industries) carries a device for HEI distributors connecting to the original tach. 

I tried the "online" do it yourself version and it didn't work.

 The aftermarket one is made by OER, part # MG019219

 

[riverdogs00]

25 minutes ago, Scott S. said:

Hey Michael,

One of Holley's affiliate companies (Classic Industries) carries a device for HEI distributors connecting to the original tach. 

I tried the "online" do it yourself version and it didn't work.

 The aftermarket one is made by OER, part # MG019219

 

I will look into it.    Interestingly, when driving at 65 mph, the tach "reads" apprx 430rpm high based on the calculators.   At 40 mph, its about 300 high.   At idle, it appears to be spot on - reading about 650/700.  I then started thinking about potential converter slippage.  The trans (TH 400) has been gone through at some point, and shifts beautifully. Not harsh, but will chirp going from 1st to 2nd under a heavy foot.  There never seems to be any laziness in 3rd gear when lightly applying more throttle.   Befuddled ha

[riverdogs00]

That tach filter part number referenced above has these associated instructions.  It appears by reversing the hook up you can have increased efficiency.  I'm not sure how that would translate though.    thoughts?

OER-040_TachometerFilter_MG019219.pdf

[riverdogs00]

20 minutes ago, riverdogs00 said:

That tach filter part number referenced above has these associated instructions.  It appears by reversing the hook up you can have increased efficiency.  I'm not sure how that would translate though.    thoughts?

OER-040_TachometerFilter_MG019219.pdf 384.83 kB · 0 downloads

Recently, I installed a vintage tach in my other 70' monte carlo, and had to use a device called a tach match. The seller does this stuff on the side and seems pretty knowledgeable, so I reached out to him about the issue noted above. He said its likely just the age of the tach causing the variance.  I asked him about the filter noted above and he offered that for $40 its worth a shot, but generally they are designed for  electrical noise which typically causes a bouncy needle, not an incorrect reading.  I'm not saying he is right or  not right - just another opinion and info is all.