Old Chevy 305 oil recommendation

captainofiron

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The only success stories surrounding a 5.0L I'm familiar with is removing it from the chassis and replacing it with anything other than another 5.0L.

However, they do seem to run forever, even when neglected. It's the modern version of the old Slant-Six. Yours even has the same oil bath down the side of the block.

I agree with the others; a 15w-40 HDEO, dino version would be my choice.
Hahaha
Yeah the truck was a great deal, I'm gonna run it until it dies then swap in a 4.6 or 5.3 LS based drivetrain
 

captainofiron

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Whatever xW30 or xW40 is on sale at Tractor Supply, Menards, or Wal-Mart. 15w40 tends to be the cheapest and will work great. I wouldn't worry about detergents too much as that engine looks spic and span inside from your pic.

I assume when you mentioned setting the "valve lash" you meant adjusting the lifter preload? A 305 will have hydraulic lifters and will want a three quarters turn of the nut past zero lash. If you adjusted it like solid lifters, you'll probably hear all kinds of funky noise.
Yeah lifter preload, turned until resistance on the pushrod then 1/2 turn more
 
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I may have missed it but make sure its not an exhaust leak or inherent header tick.

Castrol Edge 0w40 @ Walmart for $21.97 is exactly what i would put in that engine tomorrow. If it were me.
 
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I'm not really sure how many miles this thing ran, looking under the covers i was surprised how clean it was, I'm thinking due to the leak it was always running low, I was thinking the T4 10W30, but yeah maybe 15W40
I had one that the cam lobes went flat at 32,000 miles. Oil was changed @ 3,000 miles with pennzoil oil and a Fram filter. 3yrs old and GM would not warranty it.
 
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I live about 15 miles west of Austin and have a 1985 GMC conversion van with a stock 305, crappy valve seals and all. I run 1 gallon of 15w40 Rotella and a quart of 10w30 Mobil 1 I’m trying to use up. Once that M1 is used up, I’ll likely switch to the Mystik JT-8 15w50 syn blend I bought to use in my ‘74 Bonneville, ‘76 Coupe DeVille, and ‘79 Bronco. If the engine was a bit fresher, like the rebuilt 460 in my ‘77 F250 Super Cab, I’d use Mobil Delvac 1 5w40 Turbo Diesel Truck (once broken-in). Plenty of zinc in all those oils.
 
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I’ve owned numerous Chevy 305 powered vehicles and ran 10W-30 or 5W-30 in all of them. I ran 5W-30 in the ones with roller lifters, 10W-30 in the ones that weren’t roller. None of them ever failed. They chug along to +250,000miles with no issues except valve guide wear.
 
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Is it an optical illusion or is the rocker nut on number 8 run significantly further down that the others? That could indicate several things, none of them good...
 

manicrodder

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Used 20w-50 Pennzoil in the 90's for awhile in the 85 TA 305 while in Lake Havasu. Switched to 10w30 yellow bottle and got better performance and cooler operating temps.
Engine was shot at just under 100K. I continued using same oil in the new engine.
 
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I'd run whatever the heck you have, or is on the cheapest of cheap sale. Weight is no matter. Frankenbrew no big deal. As much as you want it to die and put in a real motor, a big block of course :cool:, it will run forever as long as it's got a couple of quarts in it.
 
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I ran a 1978 C10 with a 305 and always used 10-30. At 85,000 miles it needed a timing chain new gears and a cam because of two flattened lobes. The guy who did it used steel gears not nylon tipped and a Crane Economaster 2 cam and lifters. He told me to use 10-40 and I did for another 150,000 miles and sold it running like a champ.
 
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