Thread: Chevy 350 in my new 48 buick

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Originally Posted by Zombiebrew

Yes but not on the highway. Honestly I don't really care if it's 3 or 4. Overdrive would be nice but I've heard lots of good things about the th350. Cheap parts right?

The TH350 is a great tranny, but the great thing with OD is that it allows you to have reduced cruise rpm while still having a more aggressive rear gear ratio for better acceleration in the lower gears - best of both worlds.

I have been listening to debates about TH350 being the best for years. The TH350 is a great transmission that has proved it's self for many years, but as far as I am concerned, I prefer a 700R4. It has a lower 1st gear for better take off and a higher final drive that doesn't run the engine to death on the open road and gives better mileage. It can be used without a computer and is also very dependable.
What ever the transmission turns out to be, enjoy the car.

Originally Posted by Hurst01

I have been listening to debates about TH350 being the best for years. The TH350 is a great transmission that has proved it's self for many years, but as far as I am concerned, I prefer a 700R4. It has a lower 1st gear for better take off and a higher final drive that doesn't run the engine to death on the open road and gives better mileage. It can be used without a computer and is also very dependable.

...which is why I swapped the TH350 that came with the project car I picked up for a 700R4, and then bumped the rear gears from 3.00:1 to 3.55:1's. Should have a stump puller 1st but cruise out nicely on the road.

BTW, the casting numbers you gave (3970010) was used for SBC blocks with a 4.000" bore from 1969-1980, could be a 2 or 4 bolt main with the cubic inch of 302, 327, or 350. Look at the machined pad on the right side front of the engine just under the alternator. Look for a 2-3 letter code with a numeric serial number and we can get a better idea of what you have. More than likely the engine does not have a solid flat-tappet cam unless someone put it in there. Back when I was a younger man, it was believed that additives were required. It was also typical for people to run a heavier oil than required to keep up oil pressure (something that I was guilty of), but quality oils of today need no additives.
Most modern engines nowadays use 5W30, but a good quality 10W40 will work fine. I found a long time ago that it does not require a lot of oil pressure, but rather a good flow to all moving parts. I might think a bit differently if the engine was running extremely low oil pressure.

Originally Posted by Hurst01

...... when I was a younger man, it was believed that additives were required. It was also typical for people to run a heavier oil than required to keep up oil pressure (something that I was guilty of), but quality oils of today need no additives.
Most modern engines nowadays use 5W30, but a good quality 10W40 will work fine. I found a long time ago that it does not require a lot of oil pressure, but rather a good flow to all moving parts. I might think a bit differently if the engine was running extremely low oil pressure.

Hurst01, the key to your statement is "...most modern engines", and relative to older engines, an additive or ensuring that the oil selected contains the necessary levels of ZDDP is mandatory if you want the engine to last. At least ten years ago the EPA mandated a severe reduction in the levels of phosphorus in motor oil to protect the more modern (i.e. cheaper) catalytic converters from damage, and to ensure that the catalytic converters would last through the design life of the emissions system. As a result auto enthusiasts started seeing failures in high performance engines in the high friction points like cams and thrust bearings. On "newer" engines OEM's had incorporated roller lifters and roller tip rockers, not only to reduce friction but to support more aggressive ramp angles on the cam profile, so your statement "...quality oils of today need no additives" is correct, but only for engines that are designed to survive with these newer lubricants. If anyone today goes "old school" and runs a flat tappet cam they'll be wise to follow a rigid startup and break-in process, and even then if supplemental ZDDP is not added it is not unusual for a cam to flatten a lobe within a couple of thousand miles of normal service and if that happens that engine will have been circulating highly abrasive metal particles throughout, and will have to be totally torn down for a do-over, ground up. Not only have the engines changed since we were younger, but the motor oils have changed dramatically, too, and NOT for the better relative to the older engines.

I just changed the oil in it last night. I put in Valvoline VR1 racing oil. 20W-30 and a WIX filter. It was a little expensive but from what i've read it's well worth it. Thanks so much everyone. I'll be posting another thread about another small gremlin i'm chasing.

Roger, you are very correct. I have seen a many cams wiped out because of poor break-in procedures and it stands to reason that the abrasives from the cam and lifters will do great harm to the rest of the engine. I feel that the coming along of factory roller cams was one of the best improvements they could have made for engine longevity. Another thing that makes a enormous difference is the change of alloys in the block, pistons and rings. When I was a kid it was almost unheard of to have an engine that would last out of the 70,000 mile range. Nowadays, it is not unheard of for an engine to last several hundred thousand miles with proper oil changes. I have an engine sitting aside for my 29 Buick that came from a Kentucky State Police car that had over 250,000 miles on it and I can still see the factory hone marks in the cylinder walls.
I am not new to professional high performance engine building, and I totally agree with you about the use of flat tappet cams. However, I haven't lost an engine because of lubrication problems for several decades. This is a discussion that has gone on forever and will continue to go on. Different people have different experiences and something will have to take the blame for it somewhere along the line.
Just wanted to add something that I remember about Valvoline Racing Oil. In my younger street racing days I always used Valvoline oil. When I first came across Valvoline Racing oil, I had to have it. Shortly after I put it in my engine I had oil leaks everywhere. It was because of the additives they were using at the time... if you had a leak it would find it. It is not that way any more and hasn't been for a loooong time. It is an extremely good oil.

Ok I'm not sure if this is normal but now my oil pressure pegs when I step on the gas. It's an old meter and I'm not sure what it was before. Is this normal? Do I want high oil pressure as opposed to low?

When you say "it pegs", how much is that? How much does the gauge read? I have always been a big fan of higher oil pressure, but the truth is it takes a lot of HP to turn an oil pump with high pressure. That is another thing about heavier oil, it is thicker and is harder to push. The best thing about high oil pressure is that it is an indication of good bearing clearances. What does it drop to once the engine is well up to temperature?

The most important thing about oil pressure is that it is relatively steady. You don't want really high pressure and have it drop really low after it gets hot or is idling low. I have a new Silverado and I was really bummed out because of the oil pressure, 40 psi when cold and usually around 35 when running down the Interstate. My 98 Silverado stayed around 55-60 psi all the time.

The car sits at 30 psi at idle then jumps to 60 if I touch the pedal at all!

Originally Posted by Zombiebrew

The car sits at 30 psi at idle then jumps to 60 if I touch the pedal at all!

That's excellent, and normal. Don't worry about it, IMO.

Whew! Ok thanks. My only real worry is that the guage only goes to 60 so I don't know the actual pressure.

So i drained a little oil and added some 5W20 and now it seems to be at a much better range. Warms up at abou 55-60psi then drops to 30-35 idle 55-60 when i'm moving. When i drained the oil i went looking for the casting date on the block. Under the alternator mounting bracket i found the number 31284. It doesn't appear to be in the format i was expecting. Does anybody know what year block i'm looking at. oh casting number is 32 Gm 3970010.