Recommendations for 350 Chevy crate motor

[gto78]

We just got a 57 chevy that was restored and built in 1992, and the PO passed away 3 years ago. The wife selling it didn't know much about it except it's a crate motor from 1992 with 330 HP, 355 cubic inch. We don't know much more as for specs. It has a dual quad setup with edelbrock 500's. It's got 25,000 miles since new/install in 1992.

The cam is very mild, you can barely hear any rough idle. It looks like it has the fuelie/double hump heads though, which I didn't expect on a "crate motor".

So anyways, is there any recommended oil that's safe for whatever internals this engine has? I'm guessing it should use some Rotella or Delo 15W40. I've heard rumors that the crate motors are recommended to use 20W50 but only if you drive them hard. This is a weekend cruiser, no racing. We live in FL where the temps are high, and the car has working A/C. It's got a 700R4 tranny and 3.36 gears, so it's great for long drives.

 

[FL_Rob]

At 25k,it's still "tight"....why not use 10w30/40? Just curious.But in my 350 I've used 15w40 in 'winter in Florida' if we dare call it that,Rotella 5w40 as well.no problem.

 

[addyguy]

Rotella 10W-30 HDEO, or another 10W-30 HDEO.

Sounds like a VERY nice car!

 

[gto78]

With the heat in FL I figured 15/40 was safer than 10/40. I don't know what kind of pistons and rings are in it, and if it's got any roller lifters or roller rockers.

The Pontiac engines I built were basically stock specs, just new rings and bearings into a stock block. Those always needed 20W50 if driven daily, and we ran 40 wt on the one we only raced without street use.

I had posted a few months ago what the recommendation was for my 67 GTO engine and the consensus was to use Delo or Rotella 15W40 because of the zinc and phosphorous etc.

Unfortunately we have no paperwork on this 355 and I really am clueless as to who built it and to what specs. Seems like everyone in the world can build a "chevy 350 crate motor". I really wish I knew if it had chrome rings and if it has Hyper-eutectic pistons. If so I'd lean more toward 10/40 oil.

 

[gto78]

Originally Posted By: addyguy
Rotella 10W-30 HDEO, or another 10W-30 HDEO.

Sounds like a VERY nice car!


So you think 10W30? Is that common for Chevy? I'm a Pontiac person and the Chevy stuff is new to me. I don't know the internal clearances and what kind of oil passages it has etc.

BTW it's a beautiful car. You can't drive anywhere without being stopped and asked 20 questions about it. It's Merlot Red and lots of chrome, with Cragar crome wire wheels.

 

[ARCOgraphite]

Run as light as you can (rotella T 10w30) and listen to the motor and check hot oil pressure - if you get piston slap or light rod knock hot, go up 1 step to RTS 5w-40 or T 15w-40. I would NOT run any SM/GF-4 PCMO. 4T superbike oil is also an option for a high zddp oil with advanced basestocks. These are 10w-40 oils rated typ API-SH equivalent. Ignore the motorcycle on the bottle

 

[eljefino]

You might be able to make some guesses about construction with a vacuum reading at X rpm idle, and maybe pull a valve cover and measure how far the rockers travel?

I'd stick with the 15w40 for no other reason than you might get some fuel dilution with the carb.

I've heard of motors built with clearances for 20w50, but that usually comes with a "3/4 race cam" which would be lumpier than your setup.

 

[gto78]

Here's the car anyways so we know it exists lol

 

[Brons2]

330 horse 350ci is the standard GM performance parts (ZZ4?) crate engine rating. Could be a GM crate motor.

 

[lexus114]

Hold on to that one! btw love the garage too!

 

[Brons2]

GM Performance part number 19210008 is the "350HO" a 330HP 350ci engine.

 

[addyguy]

That IS a beauty!