What oils to use?

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Nov 26, 2003
Auburn WA
Hi ya all, I'm new HERE. I am currently completing a rebuild of a 82 Dodge Mirada with a 85 360 4Bbl. All new bearing, rings and seals. I am installing TOTAL SEAL Gapples rings for thier extra sealing and reduced blowby. Every one I know states to use 15w40 Dino oil forever. Car Craft Magazine just did a bild up on a 318 and the base line oil was 15w40. Then they changed to Royal Purple 10w40 and got 9 more HP at 100 less RPM. This engine should put out 1 HP per cube. I will have an oil cooler also. So what to use? Any help is needed. Thanks, DaveJ

Break it in on Delo 400, 15w-40 for at least 6000 miles before using a synthetic. If you decide to use Amsoil, their best oil for this application would be the S2000, 0w-30 during the four coldest months and S2000, 20w-50 during the eight warmest months. A max of two changes per year will be fine, even if you drive 15,000 miles annually....Oil temps will run 15F-20F cooler in the winter, so the 0w-30 will be more than thick enough.

Compared to a non friction modified, 15w-40 diesel oil, you should pick up more than 9 Hp with the Series 2000. I've seen dyno results from 3-4 years back of a 326 ci, Winston Cup engine that picked up 22 Hp with the S2000, 20w-50. Of course it was making about 525+ Hp to start with, as I recall.

Please call me in the evening or on weekends if you have specific questions.

DaveJ from Auburn - hey, another local guy! I'm beggining to the us Washingtonians really like oil.

I agree with TooSlick on break-in. Either the Delo or the Pennzoil LongLife 15W-40. You can get the LL at Fred Meyer and the Delo at Costco.

I think after the engine is broken in I would go with the Amsoil 15W-40. This oil is a real value. Take a look at the 10W-40 as well. Discounts for locals apply, the products ship out of Portland so you get them the next day.
I am also a fan of Delo, should be a fine break-in oil. I am a little more than sceptical about some of the HP claims made by synthetics, it seems the magazines see wonderfull gains while people I know that have done the same have not seen a significant difference (if any). I'm not discounting the other benifits of synth, but if your spending the extra bucks to get a 10 hp gain, don't count on it. As for which synth, I would be inclined to try the Amsoil 15w40 (based on UOA's), but then again if your after HP gain it would be wise to use the thinnest oil that will offer adaquate pertection, perhaps GC 0w30 (if you can find it).
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