I was thinking about getting some new 360 heads and installing them on my old 318, I the question I have is I was told that I cannot do this without changing my piston rings, as the new heads will blow out the old rings. Is this true, what exerance does anyone on here have to say about this?
new heads on old block
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1970Duster
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You can put 360 heads on your 318 but you'd be better off with a set of 302 head (swirl and harden seats already).
I have a line on a set of brand new 360 heads complete with rockers for 200.00 dollars. Is this a good price? I'm going to be putting this on my street car.
Will the new heads effect the old block pistons rings?
Will the new heads effect the old block pistons rings?
AdamR
Big Member
I dont think you will blow out your rings but your going to loose compression unless you mill the heads down
I remember people saying that about Chev engines I think it's an old wives tell i've never had a problem, I'm assuming your gonna with 360 heads on a 318 for more power which doesn't work cause it drops a already low CR of a 318 to in the 7's for CR. What year is your 318 and is anything done to it now? Stock heads are not too bad good to about 325hp the weakest part about a 318 is the cam then Intake,exhaust and CR. Stock long block with a comp 262, headers and 650 4bbl made 282hp.
jos51700
Green Bearing thread connoisseur
The issue the OP is talking about is putting a set of rebuilt heads of any type on a worn bottom end. The additional sealing brought about by freshened heads is disproportionate to the worn ring seal, which will cause additional blow-by and oil consumption.
In other words, it won't wear out your rings, but it will point out how crummy they actually are. The leaky valves and leaky rings got along fine but now they aren't balanced due to great valve sealing. I've seen this many times, and if your rings are worn much at all, they're gonna lose oil.
In other words, it won't wear out your rings, but it will point out how crummy they actually are. The leaky valves and leaky rings got along fine but now they aren't balanced due to great valve sealing. I've seen this many times, and if your rings are worn much at all, they're gonna lose oil.
Jos51700,
Thanks that is what I was looking for.
Thanks for the help here is what I have and plan on doing in the near future.
I have a 69 318 that has been sitting for several years and was just looking at options I'm thinking about for a build in the near future.
Thanks that is what I was looking for.
Thanks for the help here is what I have and plan on doing in the near future.
I have a 69 318 that has been sitting for several years and was just looking at options I'm thinking about for a build in the near future.
moper
Well-Known Member
x2
I was given a 88 3.9 dakato by a good friend of mine.
The truck used no oil but all at once developed a miss.
It trned out to be a burned valve.
I pulled one head, and did a valve job. Never touched the other head.
The old truck started right up and ran fine.
After that the truck started using a little oil, but that could be expected with 150,000 miles on it.
It is my 18 year old daughters only means of transportation which worked out great for me, I only ended up with $325.00 total in the truck and that included putting a new steering rack on it.
$200.00 on a fresh set of heads is a good deal, I gave $150.00 just to have one re-done on that v-6
I was given a 88 3.9 dakato by a good friend of mine.
The truck used no oil but all at once developed a miss.
It trned out to be a burned valve.
I pulled one head, and did a valve job. Never touched the other head.
The old truck started right up and ran fine.
After that the truck started using a little oil, but that could be expected with 150,000 miles on it.
It is my 18 year old daughters only means of transportation which worked out great for me, I only ended up with $325.00 total in the truck and that included putting a new steering rack on it.
$200.00 on a fresh set of heads is a good deal, I gave $150.00 just to have one re-done on that v-6
So were not suppose to tell him other pitfalls with the swap good too know!
Thanks for actually answering his question.
While it is a nice thing to do, notifying someone of the pitfalls or potential pit falls, you did not answer his question at all did you, or the rest of the replies. After all, he could have a high compression 318 already. He could have a zero deck height slug in there.
You just assumed something that may not be. And then rambled on about the pit fall. This didn't answer the question or help the posters question out now did it? Perhaps, something he already knows.
He could have a 10.86 ratio with a 318 head @ 62 cc and a 360 head at 72 cc would drop it to 9.56. Or there about.
OwdKasd
Well-Known Member
It's nearly impossible to give a definite answer. The old rings could be 95% left or 5% left. The better shape they are in, the less likely they are to "fail" or cause consumption or Blow-by. Thousands of people do top end rebuilds every day with no issues. Some Smoke or use oil afterwards. The answer is a big fat Maybe but a higher chance of being just fine.
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