conventional or synthetic??

[rydafoo]

i have a 91 s10 blzr with the 4.3 non vortec that was recently rebuilt bout 2k on the motor and 125k on the chassis, also an 87gmc s15 with the iron duke wit 95k. ive been using conventional in both (castrol gtx) but would synthetic better suit?? i appriciate your help

[oats84]

if you start runin syn you need to be dedicated to stayin i would run it in the fresh motor and a syn blend like max life in the other just my 2 cents as i run a lube shop

[82swampthing]

I use only conventional oil in my engines, usually castrol gtx.I don't trust synthetics at all.I'd say stick with the conventional oil .

[cdowns]

synthetic mobil one or royal purple are my 2favorites in everything trannies rears and wheel bearings too //theres a definate MPG advantage to using them and the cost difference isn't all that great anymore

[swb85]

It's been proven time and time again that synthetic lubricants are superior to conventional in every way. Switch to synthetic and enjoy longer change intervals and superior protection. If you're bored and want to learn more than you ever thought possible about oil, stop by here:

http://www.bobistheoilguy.com/forums/ubbthreads.php

[1968SWBBigBlock]

If these are both roller motors go synthetic
If it is a flat tappit I would stick with conventional with EOS added to preserve your camshaft

[neonlarry]

I've run nothing but synthetics since they first came on the market. I use RP now and change oil every 15-25,000 miles and I have over a million miles on my last three vehicles. I'd say it works pretty well.

[cableguy0]

synthetic is far better oil. using conventional oil past break in at this point is a waste. if you crack two identical engines open at 100k miles one having run conventional and the other running synthetic the difference is amazing in how much cleaner and how little wear will be in the engine that had synthetic

[Beuford]

I run synthetic in all my vehicles,Harley included. I run schaffer 10w-40 in my `04 Impala and the same in my `70 C20 with a modified 400 small block. They both have the friction inhibitor that flat tappets need.I've never had any problems in anything. I tow a 24ft camper with the `70 and in the hills of Pa and W Virginia it gets a workout. It's just a matter of choice as almost all of todays premium oils are ok

[Longhorn Man]

Originally Posted by oats84

if you start runin syn you need to be dedicated to stayin i would run it in the fresh motor and a syn blend like max life in the other just my 2 cents as i run a lube shop

Why would you say you need to be dedicated?
This is one of the many myths.

[JPCY72]

If you run the mobil 1 turbo diesel truck oil that has all the zddp in it that you could ever need and its syn. good thing is that you can get it at costo or sams pretty cheap. or use the rotella t syn also a great oil. the RP and the Lucas have the zddp but they are marginally more expensive and arent available everywhere.

[mcbassin]

I run both I run the cheap stuff Quaker State 5W/30 in my Pontiac Grand Am and Grand prix and Full synthetic Mobil 1 in my Trucks. For the record, I had 1988 regal that had 326k documented miles when I gave it away (never turned a wrench on the engine) Ran conventional changed ever 5-7k miles.....my 1999 Burb 4x4 has 225k miles run Mobil1 only change the oil every 12k miles. Both will give you long life more a matter of the newer engine design. They oil a lot better and the roller design gets more oil to the top end.