318 value

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Dan the man said:
All of this is way over my head. Can I get decent performance from a 8.25:1- 9.0:1 compression ratio? The reason why I was looking at closed chamber heads is for the compression, flame travel. From what I've read on the magnum / 302 heads concerning them cracking it's not a matter of if but when they will crack. Seems they are prone to cracking between the seats and naturally the crack only gets worse. I can't see putting money into cracked cylinder heads. One guy claimed that the exhaust seat came loose due to severe cracking. Is it possible to run a decent torque cam with a 8.5:1 compression ratio? I'm wanting good throttle response and strong low to midrange torque, engine speed will probably never exceed 4,800 rpm's as that's what the cam pulls to that I looked into.
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Yes, you can make good power with compression ratios in the area you are considering.

But like everything else there are other things to think about.

Lower compression ratios have less expansion ratios. You can look that up on the web and read on it. Expansion ratio is something that needs to be considered.

Also lower compression ratios generate way more exhaust gas temperature than does a higher compression ratio. The less dense air/fuel mixture in the combustion chamber burns slower so it makes more heat later in the cycle.

Lower compression ratios also require much different timing curves, including total and initial. They can be very detonation sensitive so getting the timing right is important.

Cam timing is always critical. Just as much so with those compression ratios. Trapped volume is a big deal so you want to think about how the cam numbers affect how well the cylinder traps the air/fuel mixture.

Exhaust guides could possibly need a bit more clearance depending on the valves and guide materiel. This is due to the extra heat.

Just like anything else, the more time and study you put into your combination the better it will run and behave when you are done.

The end goal is the most cylinder pressure you generate without detonation. Lower compression ratios do not always mean an engine is less detonation sensitive.
 
Dan the man said:
I recently found a 318, year, condition is unknown by the individual who has it. What makes it tempting is that it has a 340 intake manifold on it. It's complete except for the carburetor and distributor. The owner said make me a offer, but honestly I have no idea what to offer him. I don't think that he'll let me pull the oil pan either[/QUOTE For starters, there is a huge port mismatch from a 318 to a 340 head and intake so unless a lot of metal has been removed from the heads you will have real flow losses instead of gains. no need to explain what that will do for performance. Next, there is NO way you can make a 340 from a 318 by boring it! That's a difference of 0.130 in diameter and there were never any blocks cast with wall that thick except for the old X block castings from Direct Performance for race builds. Those blocks were noticeably heavier than ANY production blocks. All LA engines could be easily be dated and identified by reading the castings in the side plus the stampings on the front near the deck. If the intake is an old LD340 like appears in the photo. I didn't look at it with a sharp eye however it looks like one at first glance. Those intakes were great for multipurpose builds. But must be port matched to whatever head is installed !!!! If not, it will run but not like it could.
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toolmanmike said:
They haven't made small block LA's for how long now? If you have room to store one why scrap it?
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Agreed!!!! If you may need "ONE", one day, hang on to it. They are getting harder to come by. If not, sell it or them and let someone else that may need them, have fun. I just moved to my last home, I'm sure, and sold most everything that I will "Not" need in the future. Kept one 340 complete and running, along with a 727. Sold 318's, 340's, 360's (all running motors) and several 4-speeds and 727's. Just kept some back-up items, as interior, mechanical and electrical for my car only.
 
Swinger 340 said:
Agreed!!!! If you may need "ONE", one day, hang on to it. They are getting harder to come by. If not, sell it or them and let someone else that may need them, have fun. I just moved to my last home, I'm sure, and sold most everything that I will "Not" need in the future. Kept one 340 complete and running, along with a 727. Sold 318's, 340's, 360's (all running motors) and several 4-speeds and 727's. Just kept some back-up items, as interior, mechanical and electrical for my car only.
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340's are rare in Missouri, all mopars are for that matter
 
MOPAROFFICIAL said:
Be nice to know the casting number.
You can bore some out 4-4.04"
Look on the sides if the block for what looks like circles/templates for the core/freeze plugs. In other words.. it'll have freeze plugs but you'll see these circles where it's almost like they were going to put them there and decided not to. Those are the blocks.
2536030 iirr
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Good info u posted about comment above I always look for those circles / this is 68 model 90 over with more to spare got to Love those old Mopar engineer's !!!

20200802_180645.jpg
 
1Badcolt said:
Im Happy to say Roy sold me this ###
100 % original 1968 318 long block
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Update on the 318 I found. Owner doesn't want me to pull oil pan or valve covers. He's thinking that it's worth like $400, not to me especially since I can't hear it run or inspect it. My luck I would buy it and the block would be junk. I understand that these older cars and their parts can be hard to find but that's to much for me to take a chance on it's condition.
 
Dan the man said:
Update on the 318 I found. Owner doesn't want me to pull oil pan or valve covers. He's thinking that it's worth like $400, not to me especially since I can't hear it run or inspect it. My luck I would buy it and the block would be junk. I understand that these older cars and their parts can be hard to find but that's to much for me to take a chance on it's condition.
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Yep, that’s a HARD pass on that deal. I would look at it or tell him to stuff it.
 
i'm confused 400 dollars is too much but you were talking strokers and backup motors ain't you the guy claiming that you couldn't work on a car you needed a complete running car but there were no running mopars in missouri to be had for 20 k
 
Lowcar said:
i'm confused 400 dollars is too much but you were talking strokers and backup motors ain't you the guy claiming that you couldn't work on a car you needed a complete running car but there were no running mopars in missouri to be had for 20 k
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Never said that I couldn't work on a car. I was talking about body work. I wouldn't mind a car that needs engine work. What's wrong with investigating my opinions. $400 for a engine that I can't inspect first, no way. And as far as no A bodies in Missouri for 20k, I haven't seen any. I don't want a car that needs quarter panel work floor pans etc. If I could've pulled the pan on the 318 and it checked out okay I probably would have bought it, but not being able to inspect it first, no way
 
Lowcar said:
i'm confused 400 dollars is too much but you were talking strokers and backup motors ain't you the guy claiming that you couldn't work on a car you needed a complete running car but there were no running mopars in missouri to be had for 20 k
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I don't believe in buying something just because it might be getting harder to find. Does it make sense to pay $400 for a engine that may be junk? I've been on probably every site available and all that comes up are project cars or 30k plus cars.
 
it never hurts to be a dreamer but the truth is the old car hobby is getting more unobtainable every day for a lotta people. my advice would be never turn down a free motor delivered hell the gas money today would probally be close to 400 dollars to go get that motor
 
Lowcar said:
it never hurts to be a dreamer but the truth is the old car hobby is getting more unobtainable every day for a lotta people. my advice would be never turn down a free motor delivered hell the gas money today would probally be close to 400 dollars to go get that motor
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I agree. I wish that it would have been free and actually not far from where I live. I don't want to be negative here but the classic car market- ownership has 5 years left at best if that long. I think that us, are some what to blame as people are asking way more than what these cars are truly worth. A basket case cuda for 4k that needs everything I mean everything.
 
If I had a non running 318 and a guy was considering paying me $400, I would say, pull the whatever and put it back like you found it IF you don't want to pay me the $$$. For me that price i pretty stout for a 318 that' s not running,and to me a core.
But I am conservative by nature and necessity!
 
Yeah, 3.91 to 4 inch. The Ross pistons for it are on another thread he posted. Coming in between 12 and 12-/2:1 with the combination of heads and 3.2 inch crank.
 
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