Question on f-600 dash cluster?

[mljjones67]

I have found a gauge cluster for sale. They have it listed as a 61-66 but it looks like the one that would fit our trucks. The part number on it says its a 64. (C4TF 190529-A) if I am decoding it right. Can anyone verify if this will fit our bump? Here are some pics also.

[fordman]

the one in those pics are for our trucks. it will fit.

[mljjones67]

cool! whats up with the part # did they come in the 64 also or am I decoding it wrong?

[fordman]

the part number looks like 64 to me. that is just when the mold was made.

[Merlin68F100]

I like the round gauges more than the stock look on my 68.

[mljjones67]

Any one know what size the vacuum gauge and speedo gauge is? I am looking at a tach on ebay that is 4" round. If its the right size I will probably get it. Thanks all

[FORDification]

The stock hole for the speedometer is 3-3/4". If equipped with a tach, air pressure or vacuum gauge, the hole was 3-7/8".

[mljjones67]

Thanks Keith!!

Cool so I am guessing the actual measurements of the tach a 3 7/8. Now I need to know if I can actually make it work on my cummins conversion.
It looks to be mechanically driven. Any ideas????

[FORDification]

Should be easy enough. Just get a speedometer shop to fab up a drive cable with the necessary ends.

[mljjones67]

I wonder how I would hook it up to the cummins? Again thanks Keith!!!

[averagef250]

You need a timing cover tach drive adapter. The parts run about $500 from Cummins and drive off the IP gear and replace your oil fill. You then have to run a valve cover oil fill and those suck, they take a decade to fill the engine with oil.

You have to get a 2:1 tach since the IP is half engine speed or use a speed adapter if the ratio is different.

IMHO, mechanical tach is a bad idea with these engines. Better idea, use the vacuum gauge hole for a boost gauge or pyro.

RPM's do not matter diddly squat with these engines. You cannot run a VE pump over 3500 without serious work and they won't take it for long. Even if you had a seriously tweaked P7100 with 5000GSK you don't need a tach, the engine will not overspeed, it's impossible unless you get in a runaway situation where the engine is being fueled by a different source than the IP. This happens and the engine will self destruct regardless of a tach or not.

Boost and pyro are far more important and useful that a tach. You don't watch your RPM's, you want to keep an eye on the other stuff though. High EGT's are an instant indicator of a problem and something you have to watch in a heavy fueled engine under a load. Stock headgaskets will not hold much past 35 PSI so a boost gauge is a wise investment as well.

These engines make peak torque at 1600 RPM. Anything past about 2000 is just winding it out for the sake of winding it out unless you have some serious engine mods. No reason besides getting it into the next gear. Past 2500 you can feel the power drop off significantly.

[mljjones67]

Sounds good to me. I will look into gauges that fit the hole. thanks Dustin

[averagef250]

Forgot to mention, another reason a tach is a wasted investment is that a mechanical oil pressure gauge does pretty much the same job. Oil pressure is pretty much exactly proportional to engine speed. If you have a good 100 PSI oil pressure gauge you have a tach once you get used to driving the truck and familiarize yourself with what oil pressure the engine runs at different RPM's. 80 PSI gauges won't do it though. These engines run very high pressure in VE pickup apps without accessories bleeding off the excess pressure like air compressors and a P7100 pump. They easily peg 80 PSI gauges. 100 psi will peg cold, but will go down within a few minutes.