Great old thread... I read though it a years ago, but slept a few times since so forgive me of any oversight..

I'm considering using the Earl's "sandwich" thermostat & they make a 502, 503, & 504 in the sandwich style thermo,, I know the differance in the 02 & os is the 02 has 3/4" threads for the filter & the 03 having 13/16 but does anybody know what the differance is in the 504 part # ??

Also is anybody using these & whats your tried & tested real world experiance with them ??

I really like the fact that they simplify the amount of oil lines that have to be ran since they are block mounted & would have no more lines than a regular spin on adaptor going to the cooler..

Lastly, they say they start opening at 160 & fully open at 180 again what kind of real world oil temps are you guys seeing out of them.. (yes I know there are many variables but trying to get an idea.)

Thanks, Scott

I know a couple of people that use the sandwich style with no problems. One uses the Jeggs brand for $32.99

http://www.jegs.com/i/JEGS/555/51711...ductId=1032937

I gotta say when I seen the price you posted I thought it was gonna be the non-thermo style.. haha.. I've looked at several others but never seen that one.. I obviously like the billet Earl's over the cast but man thats a good price.. I would opt for some AN's over the barbed ends but thats a nice price & something to consider.. Thanks..

Also, Any idea what kind of real world temps they are seeing ??

The different part numbers are probably for Mark IV and Gen V & VI. The pads are different.

Just got off the phone with tech at Earl's (holley) & he couldn't really tell me much & pretty much read off what I knew already..:rolleyes:
He said the only differance he knew in the 503 & 504 is the 504 comes with the 7/8" spacer.. I attached a pic below.. If I was guessing I would say that the spacer makes it work with a 4,5 or gen 6 ? I'm running an older style mark 4..

((ONCE AGAIN I realize I can't pos pics here due to my membership running up !!! I'm gonna have to penny up & pay because between that & looking at the skinny redneck in my avatar I gots to be doing something !!))

Anyways maybe I will try to post a link..

Try this...

http://www.holley.com/504ERL.asp

I do not know the temps he was running, but all of the condensation in his valve covers disappeared. I can never find those oil thermostats when I check Jegs website. I have to Yahoo - Jegs thermostat sandwich

Also I think he mods them a little. Drills them bigger and adds the -AN fittings.
I'm going to order some up and I have oil temp gages. So I will have some # in the future.

Yeah if I went the jegs route I'm sure I would be doing some minor portwork inside of it.. possibly on the earls as well if the edges are pretty sharp,ect.. but Im sure it would need less than the cast unit.. Definatly be using AN fittings either way.. I called jegs about the gen 4-6 deal & the tech guy read me what was off the website...:grinser010:

Rookie: Do you know if the dude running the jegs unit is running a 4,5 or 6 block ??

I have never had a gen 5 or 6 block only 4's so I really don't know how much differant they are on the filter pad.. If anybody can answer which of the earls part #'s will work with my Mark IV block that would be very helpfull !!!

I just heard back from summit & they say that the Earl's part# 503 will work with a Mark IV block... Can Anybody verify this ??

((I hope I'm not de-railing a great thread by somewhat "thinking outloud" .. I just know there's some good info here & this may be helpfull to somebody else sometime down the road.. I know someboady else was asking about the Earl's sandwich thermo early in the thread & it never really got answered..))

It is not on the block, it is on the Merc remote filter pad.