[Wolfdog]

I just hit the street last week and it seems like i'm turning too many RPM's? I have an 87 Monte SS w/ a 383 , 700r4 w/ 3000 non-lock up stall tc , 3.73 gears , and a 28 in. rear tire. At around 65 mph i'm turning about 3000 RPM's. I did a few calculations and came up that i should be around 2050 @ 65mph. I know that i'm in o.d because when i downshift the RPM's shoot up. Then upshift and back down they go to 3G's. Everything else feels great. I'm using the factory tach w/ an MSD 6AL box.

Thanks,
Billy aka... wolfdog

 

[ericnova72]

Are you sure you are getting all 4 gears and it isn't staying in 3rd gear and not making the shift to OD?? 3000 rpm is about right for 1:1 drive(3rd gear in 700R4) with 3.73 and 28" tire.

I could be wrong, but doesn't the factory tach require a tach adapter to work correctly with an MSD box?? Could you be getting a bad reading??

Does it actually feel like a lot of rpm at 65?? Seat of the pants feel.

 

[Wolfdog]

I know the adapted your talking about. I thought it was to make the tach work from not working.but I'll look into it. I know, the numbers are saying 3rd gear, thats what seems so off. i'm going for another "gear counting" ride now. Thanks for the help

 

[SSedan64]

Those OEM Monte Tachs are famous for incorrect readings. Usually very high.

 

[S10xGN]

I've got a 3400 stall L/U but when it's unlocked it costs me 700 RPM @ 70 MPH.

Russ

 

[Wolfdog]

i've been digging through some old posts on the monte forum. sounds like a combo of non lock up tc and the tach being off maybe from a bad tach filter. but i still dont know for sure. ................... thanks

 

[Atomsplitter]

Me Too!

Wolfdog,
I have the same problem. I'm running 245-60R15 tires (26.5"), a 3.42 rear with a 700r4 and I turn about 3000RPM at 65. I've checked my speed with a handheld GPS and the speedo is right on! I have stopped the truck and slowly sped up till I can see the tach rise and fall with each shift till I'm in 4th gear. I do NOT have the lock-up wired yet so that should not be an issue. I'm using an aftermarket VDO gauge set. When I had the truck out last year for the first time there was a loud bang when I had slowed for a stop light and I never figured out what it was, but I do know my TV cable was not set correctly at that time.

Let me know what you find out please.