Is my tach right?

[71GMCer]

I finally have been driving around and im just questioning my tach,

Its a 350 sbc with a 4bolt main

It idles without choke at around 8-900rpm and with choke around 1000-1500rpm...my shift point is around 3000rpm because thats when it starts getting loud and obnoxious (open piped with glasspacks)


Correct? If not how do i fix it?

Also, It seems to no work after been sitting in the sun so ive been tryin to park in the shade...but once it cools down it works fine...is this normal? The back is black so it gets really hot.

Matt

[Stocker]

The numbers don't seem out of line - I assume it's a stick shift, and you chose to shift at 3000 rpm because of the sound? Mine is an auto trans and shifts at 4500 rpm under full throttle.

No idea why it would not work when hot, unless it's digital. Some LCD displays will not work after exposure to too much sunlight & heat.

[71GMCer]

ah ok awesome....its a 4speed standard....i just thought it was gonna blow the engine cuz it sounds really loud at around 3000 so thats just where i shift.

And i have a Hastings tach...not autometer quality but it still works...wonder why it doesnt seem to work after it has been in the sun

[Stocker]

Originally Posted by 71GMCer

it sounds really loud at around 3000

What kind of cooling fan? If it's fixed-blade (not a clutch fan), they can make a terrible racket just from pulling so much air.... can kinda make it sound like the engine is spinning a lot tighter than it actually is.

[Beuford]

Most newer tachs have a printed circuit board in them. If it is cracked when the sun heats it up it will expand and pull the circuit apart and stop working....just one thought. IMHO Bob

[Stocker]

^ Good thinking! Along those lines, there could also be a cold solder joint on that board. I have seen that on a Nissan my son once owned... it would kill the fuel pump. Re-soldering fixed it.