Oil choice for after break in period.

Sask84gt · Feb 28, 2026

Hey all, probably going to open a can of worms with this topic but I need some more opinions. What did everyone use for oil after they ran break in oil on a fresh build? I’ve been doing research and posted on Facebook groups and can’t really get a clear answer. It’s a 91 roller motor that’s been torn down to block, bore out to a 306, new Trickflow cam, roller rockers etc. Some say don’t use synthetic right away use conventional until 1000km or so. Others say that’s hogwash and use synthetic right after a short break in. Am I overthinking this? I tend to do that when it comes to these cars lol. Right now car has Amsoil break in oil in it and has around 250km on it. Want to change before the season starts as it’s been sitting since October. Don’t have a particular brand but I like Amsoil and was also thinking valvoline vr1

Thanks all and sorry for the wall of text lol

TTSaleen · Feb 28, 2026

I've always tried to use break-in oil for the first 400-500 miles or after a dyno session to fully seal/condition the piston rings to the cylinders.
You will get varying opinions on this, but the goal is to prevent excessive oil consumption.
My engine builders over the years have recommended a standard oil for first few hundred miles before switching to synthetic.
After that you should ask your builder what oil weight they recommend, this can vary on how they setup/clearanced the bearings.
But a safe bet is 10W-30.
My current 5.3 LS engine was just rebuilt and I am running Lucas 30W break in oil in it.
My builder told me after a few hundred miles, I can switch to 10W-40 based on how he set this up.

Good luck,
Ryan

Sask84gt · Feb 28, 2026

TTSaleen said:
I've always tried to use break-in oil for the first 400-500 miles or after a dyno session to fully seal/condition the piston rings to the cylinders.
You will get varying opinions on this, but the goal is to prevent excessive oil consumption.
My engine builders over the years have recommended a standard oil for first few hundred miles before switching to synthetic.
After that you should ask your builder what oil weight they recommend, this can vary on how they setup/clearanced the bearings.
But a safe bet is 10W-30.
My current 5.3 LS engine was just rebuilt and I am running Lucas 30W break in oil in it.
My builder told me after a few hundred miles, I can switch to 10W-40 based on how he set this up.

Good luck,
Ryan

Ok well as I’m the builder with the help of my brother I guess I need to ask myself lol.
After research I went with Amsoil break in. I started car for first time, Did a short 10 minute drive and Came back dumped oil and added new break in oil. Was told to put around 2-300k on it then go with conventional for another 500 or so then synthetic. It has about 250k on the oil right now but has been sitting since October and not sure if I should start and run with that oil sitting in there. Once I started doing more reading I now second guess everything because as you know everyone has a opinion lol

AeroCoupe · Feb 28, 2026

If you do not have converters on it then I would suggest an oil with zinc. I run Brad Penn oil in both my cars and have had great results. Guy that builds my motors runs it in his cars which make way more hp than mine and are bracket raced every year so that was good enough for me.

If you have converters and it’s a street car then break in oil, regular oil for a couple oil changes, and then synthetic is what I see quite a bit.

Sask84gt · Feb 28, 2026

AeroCoupe said:
If you do not have converters on it then I would suggest an oil with zinc. I run Brad Penn oil in both my cars and have had great results. Guy that builds my motors runs it in his cars which make way more hp than mine and are bracket raced every year so that was good enough for me.

If you have converters and it’s a street car then break in oil, regular oil for a couple oil changes, and then synthetic is what I see quite a bit.

Ok, well it’s a street car and I don’t believe I have any converters on it. Got rid of all the emissions stuff. I don’t know, I may just put some Amsoil zrod 10w30 in it and send it lol. What’s the worst thing that will happen? Lol

revhead347 · Feb 28, 2026

The 5 qt jug of Mobil 1 10W-30 that's like $26 at Walmart. Best deal there is.

Kurt

nickyb · Feb 28, 2026

I don't get why everybody is afraid of synthetic oil after break in.
All new cars run it from day one.
If you run a roller cam,roller rockers you don't need zinc additives in your oil,that's for flat tappet cams.

Sask84gt · Feb 28, 2026

nickyb said:
I don't get why everybody is afraid of synthetic oil after break in.
All new cars run it from day one.
If you run a roller cam,roller rockers you don't need zinc additives in your oil,that's for flat tappet cams.

May not need it but from what I’m seeing it’s definitely doesn’t hurt it.

AeroCoupe · Feb 28, 2026

The tolerances in the newer motors are super tight so they need oil that can get in there hence all the 5W 20 and 0W 20 stuff. An pretty much all the new cars are running semi-synthetic or full synthetic from the manufacturer. Small block Fords were not designed around synthetic oils so its not necessary to run it. You can for sure run it as a lot of folks do and if you pay attention my guess is you will get more miles out of it and the higher cost is then moot.

I think it all stems from when people ran it too quick on a new build and the rings never set and they used oil. That went all over the internet and the "don't run synthetic oil" BS was born.

I do not run it because my engine builder told me to run the Brad Penn and with all the $$$ I have spent on these motors that is what they run.

nickyb · Feb 28, 2026

Yeah a high dollar$ hi power motor run what builder recommends, but the OP is basically doing a stock build with min.upgrades and for that he will get more miles out of running synthetic after break in oil and rings will be set.
I turned 316,000 miles on my stock 5.0 and only use synthetic, with a motor craft FLA1 filter.

Sask84gt · Mar 1, 2026

nickyb said:
Yeah a high dollar$ hi power motor run what builder recommends, but the OP is basically doing a stock build with min.upgrades and for that he will get more miles out of running synthetic after break in oil and rings will be set.
I turned 316,000 miles on my stock 5.0 and only use synthetic, with a motor craft FLA1 filter.

Not to knowledgeable on engine build terms so what’s considered a stock build? I mean my motor was tore down to block, bore out, 0decked and built back up using Trickflow twisted wedge cam, pistons, heads,rockers. I’m around 9.8:1 compression ratio. Add in everything else and I was probably in the 8-9 grand range.

Noobz347 · Mar 1, 2026

Sask84gt said:
Not to knowledgeable on engine build terms so what’s considered a stock build?

A street build meant to have decent manners and run well on pump gas.

Not this:

View: https://www.youtube.com/watch?v=Q0do78JjQxI

Sask84gt · Mar 1, 2026

Noobz347 said:
A street build meant to have decent manners and run well on pump gas.

Not this:

View: https://www.youtube.com/watch?v=Q0do78JjQxI

Gotcha, thanks

HotFox · Mar 1, 2026

Run Cenpeco in everything. I can tell you of case after case of using of it my own testimonials, from both daily drivers to race engines. It was discovered by me and my dad when we were tractor pulling, the most tortured form of racing.
Scott

limp · Mar 1, 2026

Any brand new cars I run for 1000 miles and change the oil.. Good idea to change the transmission, rear ends and transfer case at the same time, as all are new and have break in metals in them....
ALL rebuilt engines have dirt in them and I change mine at 100 miles...
As said above 10-30 is probably a safe bet..
Never a believer in Amsoil until I used it in my Harley... It runs quieter... I have had good luck with VR-1....... Is Penn oil the green stuff?? I like it too..
Newer cars using the 0-20 oils I still think are used for better mileage results... I just switched my Duramax 3 liter diesel to 5-30.. Eff em....
The strength of synthetic oils is its resistance to heat.. I use it in any air cooled motor I have... My Harley, my WAY over priced ( John Deere) mower, my generator ( florida hurricanes) .... In my opinion, water cooled engines really don't need synthetic oil, but I do run it in some of them...

limp · Mar 1, 2026

TTSaleen said:
My current 5.3 LS engine was just rebuilt and I am running Lucas 30W break in oil in it.

Good luck,
Ryan

Glad I am not the only traitor on here..... My LS1 will be going in my " other project" which is a chevy...

nickyb · Mar 1, 2026

limp said:
Glad I am not the only traitor on here..... My LS1 will be going in my " other project" which is a chevy...

Not a tragedy if it goes in a bowtie as intended.
Although Chevy have been transplanted into Fords since hotrodding began.

limp · Mar 1, 2026

nickyb said:
Not a tragedy if it goes in a bowtie as intended.
Although Chevy have been transplanted into Fords since hotrodding began.

The C2 purists think I am a heretic

nickyb · Mar 3, 2026

limp said:
The C2 purists think I am a heretic

That's an oxymoron ,C2 purist don't think!

limp · Mar 4, 2026

nickyb said:
That's an oxymoron ,C2 purist don't think!

Don't you dare go to the hardware store for the bolt for that bracket.. Spend the next year looking for the " correct" one with the marks and date on it.... LOL

Oil choice for after break in period.

Member

Active Member

Member

lube between the nut and the face. I know my lubes

Member

Apparently my ex-husband made that mistake.

I gotta say i never painted my nuts, Never Ever

Member

lube between the nut and the face. I know my lubes

I gotta say i never painted my nuts, Never Ever

Member

Stangnet Facilities Maint Tech... Er... Janitor

Member

wrap a little cheese around it and its a done

wrap a little cheese around it and its a done

I gotta say i never painted my nuts, Never Ever

wrap a little cheese around it and its a done

I gotta say i never painted my nuts, Never Ever

wrap a little cheese around it and its a done

Similar threads

Privacy & Transparency

Privacy & Transparency