Upgrade cam for 79 350 small block

[Quatrefoil]

I'm considering installing a 260High Energy Cam Small Block ( A5780-260 ). New lifters, but new valve springs? Do I add Zinc to oil changes?

 

[TimAT]

You will get better results (ie., performance) by matching the springs to the cam. There are so many different specs for springs- installed height, seat pressure, rate, and coil bind that it's near impossible to guess. Many cams and lifters have been wiped with the wrong springs too.
I've noticed on my BB that it is feeling like the valves are floating way earlier than it used to- but the valve springs have not been changed since 1978 too. I'm thinking I will change them this spring.

Good news is that with a good air compressor and a couple of tools, you can swap springs without removing the heads.

As far as adding zinc,you can get the same effect by either adding GM's EOS to the oil, or using one of the oils that has a high level of zinc already in it.

 

[Hib Halverson]

Do not use GM EOS as a regular additive. It was never intended for that purpose. EOS is a break-in product when used in gasoline light-duty engines. The problem is that EOS has a lot of calcium in it and, used for long periods in a light duty gasoline engine, causes calcium deposits on piston skirts. The only way to remove them is disassemble the engine.

Also, don't get sucked in by one of those "zinc additives" on the market. Most of them leave your oil with too much ZDDP and, with "zinc", from a wear standpoint, too much is as bad as too little.

Nevertheless, with an aftermarket, flat tappet camshaft you need a higher phosphorous component in the oil and virtually all SL/or SN oils don't have enough. That's especially a problem if you're using higher tension valve springs that go with most aftermarket cams.

The best way to get the right amount of "zinc" is with an engine oil designed for use in street performance engines having aftermarket flat tappet cams. One of the best is Gibbs Driven HR Synthetic 10W30. Another excellent choice is Red Line 10W30 engine oil. If you can't quite justify the expense of a synthetic, Gibbs Driven also has a petro-based HR 10W30 which is less costly but has about the same additive package as the synthetic HR

If you're on a really super-tight budget, you can get the good wear protection, via high ZDDP content, with light truck diesel engine oils. One of the best is Chevron Delo 400LE 10W30, but it's very hard to find in quarts. The next best is Shell Rotella-T 10W30.

For more information on engine oils and aftermarket flat tappet cams, see this CAC article on engine oil for Corvettes.

 

[tnovot]

Flat tappet oil

If you're on a really super-tight budget, you can get the good wear protection, via high ZDDP content, with light truck diesel engine oils. One of the best is Chevron Delo 400LE 10W30, but it's very hard to find in quarts. The next best is Shell Rotella-T 10W30.
For more information on engine oils and aftermarket flat tappet cams, see this CAC article on engine oil for Corvettes.

Hib -
Not trying to disrespect your suggestions and knowledge but I think I remember reading a year or two ago in one or more forum posts that Shell has changed their formula for the 10-W-30 Rotella and it no longer contains the higher amounts of ZN and PH as it once did. Not sure about their diesel formulas such as 15-W-40.
Tried to do a search because there were a lot of posts about this but the search function seems to have changed in the last few years and I couldn't find anything. Hopefully someone else can chime in with the latest info.
Terry

 

[Hib Halverson]

Hib -
Not trying to disrespect your suggestions and knowledge but I think I remember reading a year or two ago in one or more forum posts that Shell has changed their formula for the 10-W-30 Rotella and it no longer contains the higher amounts of ZN and PH as it once did. Not sure about their diesel formulas such as 15-W-40.
Tried to do a search because there were a lot of posts about this but the search function seems to have changed in the last few years and I couldn't find anything. Hopefully someone else can chime in with the latest info.
Terry

I know you wouldn't disrespect me, Terry but, with all due respect back to you, "forum posts" are notoriously inaccurate.

Also, any Shell Rotella-T is a diesel engine oil.

Nevertheless, I will research the Rotella-T 10W30 issue some more and report back.