The Stovebolt Site Forums The Shop Area Engine Shop Engine swap vs Oil gauge

I tried to look it up first but couldn't find anything, in changing from a 216 to a full pressure 235, do I change the oil gauge or what cause it only reads to 30?

No need to change the gauge unless you want to . The earlier vs later models had difference calibration.

My 37 only registers 30 lbs....but I had it calibrated by D&M Restorations so that the actual pressure is "twice" what it reads, but the V8 still keeps it pegged but it hasn't hurt anything in 18 years.

I put a 235 in my 41 during total restoration. I had my gauge panel rebuilt with a gmc gauge. 0 to 60 and it works fine. You could put a new gauge in it or just watch it read 30 and know it is enough. Dave

You could also find an original 1941-46 oil pressure gauge for a GMC. The GMC gauge is 0-80 PSI as engines were already insert bearings at that time. Swapping the face plate and painting the needle to the Chevrolet color scheme will make your alteration nearly invisible. You will have to remember the true PSI as the original dash cluster glass will still read the low oil pressure markings of a splash oiler (ie, half way on the gauge will now mean 40 PSI vs the 15 PSI indicated on the glass)..

What was done with my son's 46 2 ton. Original 235 was replaced
with a 54 235 from a 1 ton truck.

I bought a NOS GMC gauge. The color is so slightly off and the
gauges so dimly lit that the color difference is not easily noticed.

Now the problem with the swap.

The gauge numbers are printed onto the instrument cluster glass.
So changing the gauge does not change the numbers.

You can buy a new GMC instrument panel glass that is a direct
bolt in for the Chevy glass.

So what is the problem?

The GMC glass will give you the correct oil pressure readings.
Though the GMC speedometer numbers are different then the
Chevy's so your speed will be off.

Buy a GMC speedometer or correct the oil pressure readings
in my head.

Correcting the oil pressure reading in my head seems easier then
getting a GMC speedometer because once that speedometer gets
change who knows what other problems will be added.

If I knew about be able to get the original oil pressure gauge
re-calculated I would of maybe went that way.

If I knew that no harm would of been done with the original
gauge being pegged maybe I would of went that way.

What I do definitely know is that I would of stayed with having the
original 46 engine being rebuilt due to all the little changes that have popped
up putting in the later "direct bolt in" 54 engine.
Jeffrey

Thanks for the help, I'll probably just leave the gauge that's in it for now, worry about it when the job is done