1967 Corvette 427 390 horsepower
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Not sure what oil to use however those old BBC's are a nice motor!
It won’t leak like crazy on synthetic if it has been rebuilt, assuming they didn’t use junk seals. IF it will “leak like crazy” then it’s time for another rebuild.
Key question - does it have an original-style flat tappet cam?
If so, then I might look for something with a decent amount (not crazy) of ZDDP. AMSOIL makes a nice classic car oil that would fit this well. The Delo would be fine, too.
What do you say, @JeffKeryk ? Any recommendations for a Corvette with a 427/390?
Key question - does it have an original-style flat tappet cam?
If so, then I might look for something with a decent amount (not crazy) of ZDDP. AMSOIL makes a nice classic car oil that would fit this well. The Delo would be fine, too.
What do you say, @JeffKeryk ? Any recommendations for a Corvette with a 427/390?
If it's already out of a vehicle, I would at the very least pull the valve covers and have a look. If it were me, I would pull the heads, use arp studs, and new head gaskets. I would look at all gaskets and replace anything suspected of leaking. But even if you don't, the big block will likely be solid even if it marks its territory.
Valvoline Vr1 has everything your big rat motor will ever need, in either mineral or full synthetic. IMO the 67 big block cars are the most desirable and most beautiful Corvette ever built. Here’s a pic of mine! 
Pics please!
Pics please!
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I had a 68 Vette with the 390 horse 427. If it's out of the vehicle personally I'd just re-seal it now and be done with it. Of course, as with any used motor, you never know what you'll find, "rebuilt" or not. But on it's own, it may seal just fine from the start, it may leak for a while then be fine, and it may just leak. The oil you put in won't matter. Big Blocks just like to have oil, they really don't care about dino, synthetic, or which weight as long as they are full. And if you don't know, 1 quart per 1000 miles is normal!
Valvoline VR1 20-50 racing oil
Here are a few previous threads on the topic of synthetic oil and leaks. Perhaps they may be of some use.
Also be aware that most synthetic oils on the market are a majority Group III base stock which is chemically similar to a Group I or Group II stock. They differ in performance, not structure.
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bobistheoilguy.com
That engine [depending on starting temps] like a 20W-50 [a 15W-40 will work as well] conventional oil change it often. No need for synthetics unless doing some serious road racing. Big block Chevy engines of that era are simple engines I really like them. Had them in cars and flat bottom drag boats we all had back in the day. Sold my last boat in 2004.
I would run a 15w-40 in that engine. Something like Rotella or Mobil Delvac.
How are you gong to drive it?
If you plan on giving her free rein often (and why not!), I would run a Mercruiser I/O 4 stroke oil
I am not a fan of Diesel oil in a gasoline engine.
If just low effort cruising, a 10W30 should do fine if the rebuilder didnt mess up something.
What is you hot oil pressure now at idle and 3000 rpm?
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You’re getting a lot of personal opinions here and here’s mine. While the engine is out of the car invest in an re-ring kit with Felpro gaskets and seals. Have the valves and seats refaced, have the guides checked and replaced as necessary. Also have the guides machined for quality valve seals. I like these: Comp Cams 515-16. The 390 horsepower power cam will be lazy if the engine was overhauled with low compression pistons. If so, there are cams designed for low compression that will make decent power. Call Straub Cams to grind a perfect cam based on what you plan to do with the engine. They will also recommend the oil as well. Money well spent.
Have you been able to hear this motor run before it was removed from whatever vehicle it was in? If it's been 12 years and a 'few miles", I would at least reseal the engine—front and rear main seals, etc. I think the biggest issue would be if the heads were up to unleaded gas standards. The reasoning for the removal and the few miles driven would be my biggest concerns. As for oil, any 15w-40 would serve your needs nicely.
If it has very low miles, use conventional to make sure rings are seated in. After that you should be able to use a synthetic. The reason the topic of leaks comes up is because when it is used in an engine that has miles on it and no synthetic use is the synthetic will clean deposits around the seals and gaskets causing leaks. I recently rebuilt a 390 FE Ford sealed in rings with conventional with zinc additive. Then switched to synthetic with zinc additive. No leaks. 10w30 synthetic and a flat tappet cam.
It is impossible to answer this question without understanding the internals and intended use. If you suspect it is a mild flat tappet cam with stock springs, I would run that Castrol Hot Rod oil. HDEO used to be the ticket, but no longer because there are better options today. If the engine has higher spring pressure, you might need to play chemist and add ZDDP.
How many miles will this engine see? What's the intended use?
What would I do? Let's just say if I ever pull the engine out of my Vette or Oldsey, I will stab a mild hydraulic roller and run M1. Don't get me started!
Good luck and enjoy your BB. The 427 Mark IV is a legend. Post the engine code from the engine pad. You have a very valuable block, first year of the 427 Corvette. The 67 Corvette was debadged and got everything right. It sold poorly because everyone was expecting the Mako. Wow, I am jealous!
The IM designates a late build 66 or 67 427 390 Corvette engine. The serial numbers below match the frame and body of the specific car.
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a great ride, enjoy it!!! from 63 on GM made a sporty sports car + big block power is great if you can feed it $$$, also watch the heat gauge in slow traffic as thats a LOT to cool when theres little airflow aka local driving. i had a 64 327-300 coupe 4 spd of course that i enjoyed except in the heat, no AC + did not even know about the rear vent fan that was rugged over, but after learning about it found it did not run! today i would enjoy a 63 to 67 convert, mild small block BUT $$$$$, prolly the best lookin vettes ever IMO!!
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How about Castrol gtx classic 20w50? Can easily pick it up at Walmart too!
I have 6 qts on the shelf. Good stuff.
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What do you use it in brotha?
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