66 390 hp oil pressure gauge 60 or 80 lbs??

[Gordon A.]

We have had a lot of discussion with the gauge restoration shop [of great repute] which disagrees with the Fourth Edition of the Judging Manual page 23 which states that the 427/390 hp car had a 60 lb gauge except in the "rare occassion."

He states that almost always these cars had 80 lb. gauges. I don't care, but I want it right.

Does anyone know what is actually the current NCRS view of this? Perhaps there has been some new insight on this since the manual came out in 2004!

[Michael H.]

Re: 66 390 hp oil pressure gauge 60 or 80 lbs??

these cars had 80 lb. gauges. I don't care, but I want it right.

Your friend at the shop is absolutely correct. For 66, the oil pressure guage for a 390 HP was indeed an 80#. That changed for 67 and the same engine used a 60#.

I suppose it's possible that a few 66 390 HP's may have the 60# but that would be rare, if it ever happened at all.

[Mike Z.]

Re: 66 390 hp oil pressure gauge 60 or 80 lbs??

Gordon-
To start a data base for you, my very original 66 390hp car has an 80# gauge-build date on the car was Feb 6, 1966.
Mike Zamora
#12455

[Jim H.]

Re: 66 390 hp oil pressure gauge 60 or 80 lbs??

Hi Group,
My '66 427/390 car was original and mine had an 80# gauge.
Jim
Colorado 43119

[Gary J.]

Re: 66 390 hp oil pressure gauge 60 or 80 lbs??

My June car has the #80 guage.

[Duke W.]

Re: 66 390 hp oil pressure gauge 60 or 80 lbs??

Your friend at the shop is absolutely correct. For 66, the oil pressure guage for a 390 HP was indeed an 80#. That changed for 67 and the same engine used a 60#.

I suppose it's possible that a few 66 390 HP's may have the 60# but that would be rare, if it ever happened at all.

According to my copy of the '67 AMA specs all 427 CID Corvette engines have an oil pressure spec of 50-75 psi hot at 2000 engine RPM.

So if the '67 390/400 HP engines only have 60 psi gages, a lot of them may be pegged most of the time.

Duke

[Wayne M.]

Re: 66 390 hp oil pressure gauge 60 or 80 lbs??

According to my copy of the '67 AMA specs all 427 CID Corvette engines have an oil pressure spec of 50-75 psi hot at 2000 engine RPM.

So if the '67 390/400 HP engines only have 60 psi gages, a lot of them may be pegged most of the time.

Duke

Duke; others -- this BB oil pressure thing must have caused quite a kerfuffle in the '66-67 period. Chevrolet Service News, March 1966 issued this paragraph (sorry for the reflection). Apparently dealers are instructed to IGNORE the info of the page 17 of the Power Train section of the 1966 Product Data Book as being incorrect. They then show a table of RPM versus oil pressure for both hydraulic and solid lifters. Should be noted (as said) that these are MINIMUM pressures from an engine with MAXIMUM specified clearances.

This paragraph was repeated practically verbatim the next year in Chevrolet service News, so customers must have been complaining about low gauge readings for a while.

[Duke W.]

Re: 66 390 hp oil pressure gauge 60 or 80 lbs??

Good find! I'm surprised the AMA specs were not corrected, since this document was "maintained" as any other engineering document.

So what do '67-up 427s run for typical hot oil pressure at cruise? Anyone have any data?

According to my P&A catalog, SHP (mechanical lifter) BBs of the era use a different oil pump part number than hydraulic lifter versions, but I don't know if that means the relief spring is different, pump delivery volume is different, or both.

Duke

[Michael H.]

Re: 66 390 hp oil pressure gauge 60 or 80 lbs??

So what do '67-up 427s run for typical hot oil pressure at cruise? Anyone have any data?

According to my P&A catalog, SHP (mechanical lifter) BBs of the era use a different oil pump part number than hydraulic lifter versions, but I don't know if that means the relief spring is different, pump delivery volume is different, or both.

Duke

With 10-30 oil and at operating temp, my 66 425 HP has around 18 psi at idle and, if I remember correctly, 40 or 50 at 3000 RPM.

I think the 66-67 big block pumps are the same other than the bypass spring.

[Hal J.]

Re: 66 390 hp oil pressure gauge 60 or 80 lbs??

My October 65 390 coupe has 80#

[David C.]

Re: 66 390 hp oil pressure gauge 60 or 80 lbs??

My July 19Th, 1966 390 car has original 80# gauge

[Duke W.]

Re: 66 390 hp oil pressure gauge 60 or 80 lbs??

So, what is the normal hot oil pressure at 2000-3000 revs?

Duke

[Michael H.]

Re: 66 390 hp oil pressure gauge 60 or 80 lbs??

We have had a lot of discussion with the gauge restoration shop [of great repute] which disagrees with the Fourth Edition of the Judging Manual page 23 which states that the 427/390 hp car had a 60 lb gauge except in the "rare occassion."

I think the original problem/confusion originated from the info in the parts book. My 1966 printing of the book incorrectly calls for a 60# gauge for all hydraulic lifter engines for the 66 model year, which would include the 390 HP 427.

If the 60# actually was the correct gauge for a 66 390 HP, the instrument cluster would have been the exact same as a 300 HP/base engine. Low tach redline and 60#. The part number sticker on the back of the cluster assembly would have been the same as a 300 HP.

Does anyone happen to have the cluster assy part number from a 66 390 HP car?

[Ronald L.]

Re: 66 390 hp oil pressure gauge 60 or 80 lbs??

Attached is a pic of my 66 390 un molested, save the temp gage, we bench tested that and then sender together and in car they still don't work!@!


the cluster part number matches the AIM page F365 - 6457983 for L36 option.


But we are on oil & oil pumps, mine is original right now, think it was as has been described above, gage 80# and well in another post thinking to change the pump since I have the pan off. opinions???

[Nick L.]

Re: 66 390 hp oil pressure gauge 60 or 80 lbs??

So if the '67 390/400 HP engines only have 60 psi gages, a lot of them may be pegged most of the time.

Duke

Mine certainly is.