Hot Rods stock 392 hemi rpm range?

Anybody know what the good usable rpm range for a stock street driven 392 hemi would be? I know a lot of variables will effect it. But what rpm range is a good streetable motor going to be doing on average?

I found an old tach. I was thinking might be cool for my project but it only goes to 4K. Seems kind of low. But I'm not planning this to be any kind of high rpm project. So wondering if 4K is enough to be worth using.

 

If you like that tach, run it- you wont break 4k in normal driving, and if you do like to occasionally get rowdy, you can always buy one of those shift lights that has a dial or rpm pill, hide it behind the dash with only the light shining through.

 

Good stuff..

 

OK, here's the next possibly stupid question and the part where you can tell I barely know what the heck I am even talking about; I have a vintage hemi Mallory dual point Rev-Pol dist. that doesn't appear to have any outlet for a mech. tach. drive. I am assuming that means doing a mech. tach will not really be possible so, might be a deal killer for this tach anyway.

I have the dist, but not the tach yet. Any other way to make a mech. tach. work with this set up? What about an elec. tach.? I'm trying to avoid using anything new if I possibly can so don't want to go the elec. tach. route as I'm guessing that is newer. I really want to stick with late 50's - early 60's parts if I can.

Besides dropping some big dough on an coveted period SW tach. anybody have any other suggestions for a period correct tach. that would look at home inside a sleeper type 50's pickup? Trying to avoid anything too conspicuous or hot rod looking. Something kind of small and simple would be fine.

 

Here's what I settled on. It's an electric SW that doesn't need a separate unit. I don't plan on running it much over 5 grand too often, anyway...and the engine IS a Mopar...

 

In 1960-61,my basically stock 354 in 36 ford coupe would pump up the hydraulic lifters at about 5000 rpms. I only got there when I missed a shift or something. But everything in between was awesome.

Tom in White City

 

Ya might try asking these people to see if there is something like maybe a splitter cable that can be used.
http://www.speedometersolutions.com/

 

Troll thru ebay, there are always a few 'old looking' tachs, both dash and column mounts.

As to rpm range, most of the EarlyHemi engines are pretty much done by 5500 unless you have designed the package with something else in mind, and most 'normal' driving will be below 4k.

.

 

There are some generators with tach drive. May be able to adapt to your engine using case from Chevy........ Just depends on how bad you want a mechanical tach.

http://www.ecklers.com/corvette-generator-tachometer-drive-unit-with-gears-1955-1961.html

 

This tach came from a 1958 Dodge D700 with a 354 hemi. It's mechanical with an hour meter or rev counter, not sure. This will be added to my '58 D400 1-1/2 ton truck.

 

Steve, nice, that is cool. The one I was looking at was for a Studebaker truck and has an hours meter as well, but quite as cool looking as that one. If I could get another one of those and figure out the mechanical drive part of it, I'd be happy with something like that too.

I don't think the stock Mopar dist. I have for the motor has a drive either as I guess most cars wouldn't have has a tach. Does your dist. have the tach. drive on it? Maybe the trucks had a different model dist.

I am planning to use the stock Mopar generator with the integral power steering pump on it. I don't think it has a tach drive, but I'll check and maybe get lucky on that.

 

He said he didn't have a mechanical tach drive on his distributor, so a splitter wouldn't work either. Unless you're suggesting that he drive the tach from the transmission speedo drive, which wouldn't be worth a crap.

 

Stude, my 354 distributor does not have the mechanical tach drive any more. So my plan is to have the tach rebuilt with electronics. The rev meter may not work from that sort of upgrade but what the heck. I'll have the meter repainted and the numbers set to 001958. My other tach, same model, has 586849x1000 revs on it. Maybe I should buy the other 354 hemi from the tach above.

 

I couldn't help myself. I found the gentlemans number, called him, made the deal and now I have another 1958 Dodge truck 354 hemi.

Did I mean another hole in my head?

Stude, I think this engine still has the tach drive in the distributor.

 

when it stops pulling ,,,,,,shift !!!!!!

 

Oops, you're right, misread it.

 

That's cool. hard to have enough hemis. Now you just need another project to put it in.

I think I lost track. You now have (2) stock distributors, but only one has the tach. drive? And you have (2) of those tachs? If so, is one a spare and maybe available? I'm thinking I want to stick with my Mallory unit and hopefully there is a way to make it work with a vintage tach one way or another.

Maybe I should contact GMCBubba and see what he might suggest on how to go from here.

 

Stude, I may part with one but they both need to be completely redone. I did a search for instrument repairs and found a few links on the H.A.M.B.

http://www.jalopyjournal.com/forum/showthread.php?t=444739&highlight=instrument+repairs

My spare tach needs glass, pointers and such. So both tachs would need to be sent out together for repairs just to mimic the exact visual configuration.

Actually, I'll be going with electronic ignition and fuel injection. The fuel injection system I've been considering are from the following folks:

http://www.retrotekspeed.com/produc...ies/2x2-tb-kit/2x2-throttle-bodies-2-inj.html

With some custom designing this will be matched to my 354 hemi truck 2x1 intake manifold. This thread of yours put a fire under me to grab that other 354. It's a very lightly used engine from what the son of the trucks owner told me. I already have the NP540o overdrive trans from it. So another road trip is in order - 600 or so miles.

 

Soundfs good Steve, let me ponder on the tach and see if it might be a good option for me. I am leaning to just keeping mine all points and mech. for now.

Here is a pic of my dist. Can anybody tell me if this looks like it has a mech. tach drive, maybe where I have the blue and green arrows pointing to perhaps?

 

Here is a pic of a tach drive dizzy...note the large threaded 'knob' where a cable attaches.

 

Thanks for that pics. That is like what I thought they are suppose to be. I was wondering if those parts on mine are maybe where a fitting could be added or something or maybe some odd type of drive connection or something.

If I use an electric tach., how does that connect to the motor and get the signal? Can I use my old Mallory unit with an electric tach.? What about those old sun "football" tachs. Looks like there are a few of those on ebay for decent money. But, seems like the sending unit is the weak link on those.

 

An option for a mech tach drive is to run an early vette generator, or possable ford tractor generator(1970's???), they have a drive on the end of them

 

Can't just 'add a fitting', remember, there is a very small worm gear inside to change rotation 90*.
Usually, an electric tach get a signal from the coil. And yes, the old Sun sending units can be problematic.

If you want to run a mech tach there are other ways to go in addtion to a generator drive... The truck engines often had a mech drive but you will need both the dist and the int shaft assembly as it is very unique. You can convert any of the iron housing dizzys to electronic if needed.
.

 

Sounds like my life might be a lot easier if I stick to an electronic tach. Can those basically just work with any coil or are there restrictions to consider? How does a tach. 'know' what the rpm of the motor is from the coil?

 

The tacho picks up the pulses created at the coil from the points opening and closing. Accordingly the tacho must be set for an 8 cyl engine.

Newer tachos these days have a switch on them somewhere that allows you to switch from 4-6-8 cylinders.

Older tachos don't usually have that feature and need to be taken to an auto instrument shop to be adjusted.

 

So every 8 pulses is 1 rpm I guess. I kind of thought but seems a less than accurate way of doing that considering older electronics. But, maybe it is still accurate enough I guess. I assume this works with any coil including the typical Mallory Voltmaster ones I'm planning to use with this dist.

 

This thread reminds me of the time I saw something shiny in the ditch. I picked it up cleaned it off and said I can build a car out of this...LOL

Good Luck!

 

True enough. That's seems like a pretty good description of my method a lot of the time.

'Hey, this looks cool and sort of usable. I'll make this work somehow.'

Add that to I don't know what I am doing most of the time either and that's the magic formula for my success.

 

Just got this today. Should do the trick. Now need to get a good working sending unit for it and should be good to go. I understand the Sun senders have some problems and might need a conversion of some sort. Perhaps because of an internal battery that is no longer available or something like that. Anybody got some specifics on that and how to resolve if needed? Thanks.





Sent from my iPhone using TJJ

 

NOS !! Absolutely amazing.

Would you care to scan and post the install/wiring schematic?

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