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Discussion Starter #1
Im new to the LT1 and to modified LT1 engines.I have a 1994 Z28 has a small build and 3200 stall and a tune.It has a TCI trans 4A.Somebody give me a idea on whet they use.Do I want to go with a 20w-50 oil.I got on bobis theoilguy.com.Ive read alot on the subject but I would like to hear some opinions.
 

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I use Mobil1 5W-30 but MY engine is completely stock.
 

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Im new to the LT1 and to modified LT1 engines.I have a 1994 Z28 has a small build and 3200 stall and a tune.It has a TCI trans 4A.Somebody give me a idea on whet they use.Do I want to go with a 20w-50 oil.I got on bobis theoilguy.com.Ive read alot on the subject but I would like to hear some opinions.
a non-modified smallblock should always use 5w30, 10w30, or 10w40. there is an SAE oil viscosity chart in your owners manual if you want to know the temperature ranges, you want to compare them to your local weather...

with cold start with hydraulic valvetrains (like yours), 5w or 10w is as thick as you want.

20w50 is more for big loose flat tappet solid lifter engines to keep them from exploding, it will increase friction and probably you will lose power...
 

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yep, I agree with everyone that has posted,I use 10-30 Mobil 1 high mileage,because it has a little more phosperous and zinc than the regular Mob 1. ed
 

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i run non-synthetic marine 10w30 just because i have it laying around at work. it has all those nasty cat-poisoning additives you just dont get in 'emissions compatible' oil.

then i throw in a bottle of gm engine oil suppliment, which seems to shut up the lifters a bit, and it over-fills me by 500ml, which i like, otherwise i get a bit of pump cavitation and pressure loss during high rpm hill climbs...

EOS is good stuff, everyone should use it.
 

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I use mobile 10w30 and 1 bottle of Lucas oil stabilizer. I didn't use the stabilizer until after the engine was broke in. I used the lucas in a past SBC and it saw north of 300,000 miles and when pulled apart looked amazing inside. The engine never actually died the truck rusted away around it
 

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Discussion Starter #10
Thanks for the help everyone.
 

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Would you guys still recommend Mobil synthetic 5w30 for a 355ci LT1 cammed, ported heads, new rods, pistons, etc?
 

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I use Valvoline 10w-40 Synthetic.
 

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Would you guys still recommend Mobil synthetic 5w30 for a 355ci LT1 cammed, ported heads, new rods, pistons, etc?
If the engine is brand new ,zero miles on it ,you should probably not use
synthetic for about 2500 miles,"they say" synthetic oil will not allow
the piston rings to seat correctly,which I kind of get,but on the other hand Corvretes and Porsches come with synthetic oil from the factory,so who is correct? ed
 

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Oh wow I had no idea. Thanks guys!
 

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I thought that the new corvettes, come with synthetic in them from the factory.
 

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I have heads and on mine i run royal purple 5-30 i like it seems to work good for me
 

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If the engine is brand new ,zero miles on it ,you should probably not use
synthetic for about 2500 miles,"they say" synthetic oil will not allow
the piston rings to seat correctly,which I kind of get,but on the other hand Corvretes and Porsches come with synthetic oil from the factory,so who is correct? ed
Perhaps those engine were already run in to some extent. They have the means to do it, like I saw in the new COPO build video.
 

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Perhaps those engine were already run in to some extent. They have the means to do it, like I saw in the new COPO build video.

what is run in? hours, heat, rpm?
 
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