i just installed a tachometer on my '66 289. i was wondering about it because my idle is 500 rpm, and redline is at 4000 rpm. is this normal for my engine? or is the tachometer setup properly. i know it was installed correctly and it is on the setting for 8 cylinders.

 

Automatic or manual ?

And you say your redline is 4000 ? How are you determining this. Is that where the engine falls off ? Will it not rev past 4000?

 

hiya ... i have a manual gearbox mostly stock 289 (as well from 66).
i sometimes push it to 4500 but that already is screaming. so if you want to do your engine a favour don't push it over this 4000 when possible.
Idle of 500 sounds very low though. a stock 289 should be around 700 (650-750)

as well to blue's question, is your engine stock ? at the same time get a multimeter with a tach or a timing light with tach. quite sure one of your buddies will have one. This is the only way to verify the tach being correct. some of them can be adjusted ... so maybe someone fooled with it.

 

well its automatic...and i determined 4k, because at that point it begins to backfire from somewhere inside. but once i got it to 4500 and at around there, all power just dropped

 

sounds like you have some pretty big engine issues to work out.

My engine runs smooth as possum crap at 4,000 rpm still good at 5,000 (but I avoid going past 4,000 as much as possible)

might want to start by checking timing.

And yeah I would know... I had pet possums.

-Gun

 

Check the timming and the DWELL. The points may be bouncing all over the place at high RPM.

This assumes that you are running a stock distributor.

 

good idea with the points.
i have HEI, so i don't know those problems. Check your dwell before the timing. as changing dwell affects timing, but not the other way round. Best idea might be to replace points or go HEI if you can afford it at tyhe moment if that's not done yet.
If it starts backfiring and loosing power then by all accounts AVOID doing that. this might well fry your engine