Engine oil
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Heel & Toe
Joined: Feb 2024
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Engine oil
I have a 78 that had its motor done over years ago. Put in a 3/4 racing cam and double eyebrow pistons when bored out. Sellers says it now 333 HP? . With this work being done on the engine what type oil should I use ? Synthetic or Regular ? Also 30w or 40 w? I asked owner but his memory is going and he has no answer.
Melting Slicks
Joined: Sep 2010
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Oil wise I would start with a zinc type 10-30 dino oil. Run it a bit to break in the cam. Then drop the oil and filter adding more zinc 10-30 dino oil. Then maybe after 500? miles go to Mobil 1 or something similar.
Man it's been many moons I have heard of a 3/4 race cam. LOL.
Man it's been many moons I have heard of a 3/4 race cam. LOL.
Burning Brakes
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2023 C3 of the Year Finalist - Modified
Many opinions on oils here, you’ll get answers supporting both. I prefer regular oil on older motors.
for breaking in motors, I use Lucas break in oil 30 weight.
After break in I run Lucas hot rod and classic oil, 10-30. Great for flat tappets without a catalytic converter.
I wonder if Europeans say things like, Im running a 19mm cam? Lol
for breaking in motors, I use Lucas break in oil 30 weight.
After break in I run Lucas hot rod and classic oil, 10-30. Great for flat tappets without a catalytic converter.
I wonder if Europeans say things like, Im running a 19mm cam? Lol
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3/4 race cam? Is that like muffler bearings?
At any rate, what oil you need depends on wheather that only 3/4 of a race cam is flat tappet or roller. And the climate you live in.
At any rate, what oil you need depends on wheather that only 3/4 of a race cam is flat tappet or roller. And the climate you live in.
Is my vette stock?? HAHA
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3/4 race cams is jargon from the 70s and early 80s...so ya its been a while. As for oil I use Mobil1 20-50 for the High ZDDP which is zinc and phosphates. Without them your 3/4 cam will be a 1/4 cam in no time. The lobes will get ground right off. As for the pistons they are probably flat tops which could be the stock style by the description but there is no way of knowing the cam specs without the numbers or the compression without the heads combustion chamber size. You could go through the trouble of actually measuring the valve travel and dividing the travel by 1.5 to get the cam lift but you wont get the duration or the lobe seperation. 330 hp is not unreasonable at all, the stock 327s had 300 hp so a 350 could easily be 330hp with flat tops and decent heads with good compression and an aftermarket cam
Drifting
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Isky cams back in the old days offered 1/2,3/4 and full race cams. Ohhhh and the great isky mega cam!
Last edited by Mdbirk; Apr 29, 2024 at 07:48 PM.
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Race Director
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I remember hearing that 3/4 race cam jargon back when I was in High school. And that's a long time ago now gentlemen. And I thought it was horse **** then.
Thus my comment on muffler bearings.
If I purchased a car and the seller gave me silly information like that I would question it. At the very least I would assume the engine is bone stock and the guy is full of it.
The history of how this terminology came about back in the day is interesting nonetheless. I can appreciate marketing.
So, is my Xtream Energy 268 a 3/4 race? Maybe a 5/8ths? Sounds kinda silly doesn't it.
But marketing back in the 60's. Yup, I get it.
Thus my comment on muffler bearings.
If I purchased a car and the seller gave me silly information like that I would question it. At the very least I would assume the engine is bone stock and the guy is full of it.
The history of how this terminology came about back in the day is interesting nonetheless. I can appreciate marketing.
So, is my Xtream Energy 268 a 3/4 race? Maybe a 5/8ths? Sounds kinda silly doesn't it.
But marketing back in the 60's. Yup, I get it.
Race Director
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But perhaps the OP can do all of that!
Drifting
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I remember hearing that 3/4 race cam jargon back when I was in High school. And that's a long time ago now gentlemen. And I thought it was horse **** then.
Thus my comment on muffler bearings.
If I purchased a car and the seller gave me silly information like that I would question it. At the very least I would assume the engine is bone stock and the guy is full of it.
The history of how this terminology came about back in the day is interesting nonetheless. I can appreciate marketing.
So, is my Xtream Energy 268 a 3/4 race? Maybe a 5/8ths? Sounds kinda silly doesn't it.
But marketing back in the 60's. Yup, I get it.
Thus my comment on muffler bearings.
If I purchased a car and the seller gave me silly information like that I would question it. At the very least I would assume the engine is bone stock and the guy is full of it.
The history of how this terminology came about back in the day is interesting nonetheless. I can appreciate marketing.
So, is my Xtream Energy 268 a 3/4 race? Maybe a 5/8ths? Sounds kinda silly doesn't it.
But marketing back in the 60's. Yup, I get it.
Is my vette stock?? HAHA
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I remember them in the old PAW catalogs
2026 Loser of the Year
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From: New Or-leens Loo-z-anna
Rookie question......
Do "modern" engines have what would be considered high compression (compared to a '68 327/300)?
I ask because the synthetic "oil" I went to did not make it to the 5,000 oil change in an older engine...
also there was noticeably more engine "noise" after 2,000 miles of driving with the synthetic oil.
I went back to 30wt dino oil.
Do "modern" engines have what would be considered high compression (compared to a '68 327/300)?
I ask because the synthetic "oil" I went to did not make it to the 5,000 oil change in an older engine...
also there was noticeably more engine "noise" after 2,000 miles of driving with the synthetic oil.
I went back to 30wt dino oil.
Is my vette stock?? HAHA
Joined: Oct 2015
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From: Im not allowed to tell you
2020 C3 of the Year Finalist - Modified
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Regular synthetic oils don't have the zinc and phosphorus that are needed in a flat tappet engine. All the engines were basically roller cams after 87 and the oils lacked enough zddp after 93. So you may have lost a little metal off your cam or hopefully your lifters just weren't pumping up....
Compression has nothing to do with it but yes, the naturally aspirated v8s that are running around above 400 hp have atleat 10:1 compression. If you start wondering about octane ratios, 10:1 motors can still run 87 with knock sensors and variable timing easily
Compression has nothing to do with it but yes, the naturally aspirated v8s that are running around above 400 hp have atleat 10:1 compression. If you start wondering about octane ratios, 10:1 motors can still run 87 with knock sensors and variable timing easily
Drifting
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Safety Car
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it used to be that you could also buy ZDDT additive at one time, not sure if it is still available however. as another alternative (and if cost is of only slight concern) would be to look at the joe gibbs line of oils with sufficient levels of ZDDT etc already in them.
