new guy to big blocks.

hey I am new to big blocks and have a couple of questions. I have heard that running 15w40 diesel oil will make the engine last longer is this true? i have a 2000 gmc k2500 with a 454 in it (I am not looking to make tons of horse power). also I was told that it is ok to plug the oil cooler ports that are next to the oil filter. is this ok to do? the reason for wanting to plug them is that I spun a rod bearing and I am in the middle of the re-build if I cannot plug the cooler ports I will need to run a after market cooler so I dont get the old oil that has bearing crap in it in the nice clean block and I dont tow mutch. I would like to save the money if I can plug the cooler ports. thanks for all the help!!!!

I am going to be watching to see what info you get on the plugging subject, as I posted a similar question earlier, lotsa views, no replies. I believe 1-2 internal plugs or "redirect" valves need to be removed or reinstalled to do this, but I have not been able to find out exactly what I need to do. Don't want to do the wrong thing or plug the wrong port and frag the motor. May just suffer and run the cooler, motor is planned for a 71 Vette.

On cleaning your existing cooler and lines, should be able to use some kind of solvent or parts cleaner and run it thru and flush it out. Maybe a radiator shop, or even and AC shop could help. The AC guys have to clean condensors and evaps all the time when a compressor destroys itself.

Finally, out here in SoCal, the you-pull-its have lots of later GM trucks and vans with big blocks and/or oil coolers. Maybe you could find a clean on in a yard?

Good luck,
Tom

Thats an interesting question. I'm not sure if I can answer it for you but I have been doing some reading on the subject lately.
If it's a markIV block with a flat tappet cam I just got done freshening up the exact same engine and you can see some pics of the results on a different thread. If it's a Gen VI like I think it is then it's a roller cam and regular conventional oil is all you really need.
Now from what I understand most conventional oils have reduced their zinc and phosphorous levels down to a point where it is not flat tappet friendly. The newer cars are coming out with rollers and it just isn't necessary to put all that extra stuff in it any more. The diesel oils still have a higher amount of these additives in it and it was suggested by many that I use this diesel oil to break in my new flat tappet cam. (I didn't listen). It seems to me that if it were better to break the cam in with this oil, maybe it would be better to keep using it, at least as an additive, but I really don't know.
A member named 30-a-rider told me about this link where they mention the convention oils that are still out there and their ZDDP levels. They don't really compare it to the diesels though. http://www.chevelles.com/forums/showthread.php?t=195620
Like I said, if you have a roller engine like I think you do, you don't have to worry about any of this, just get the conventional.
I don't know, maybe it helps maybe it won't I just figured I'd share it with you since I just went through all this.
About the oil cooler, If you have it use it. Just get some Simple Green and flush it out a few times. Use a garden hose and a good nosel then some compressed air to dry it out.
questions.

First of all Welcome Chevygod. If it was me I would clean out the oil cooler you may find you need the cooler if you do any towing...Dennis:)

well thanks for all the advise I have decided to re-use the cooler. and yes you were right wrenchaholic it is a roller lifter motor and with the advise you gave me I have also decided to run a good conventional engine oil. thanks to all for the help.