70 318 with 340 internals/Cyl Head

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mario03srt

mario03srt

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All,

I'l looking seriously at a 73 Duster that has 70 340 internals and heads in a 70 318 +.030 motor. It also has a 340 torker, some mild cam and headers. What exactly kind of brew is this and what is it's output potential? What kind of comp ratio are we talking and cubic inches? It has a 3800 stall conv and a 3.55 gear.

Thanks,
Marion
 
The only internals it can have would be the camshaft. If it's a 318 with 340 heads, it has compression down in the 7s. It's still a 318. Although .030 over.
 
RRR is probably correct, 318/340 cranks are the same stroke. bore is the big difference. Very few 318 blocks can be punched out to a 340 bore. ( would need a bunch of sonic testing to know its going to be good after boring). not worth it to most guys.
 
3.91 + .030 = NOT A 340! It’s 323 cubic inches.
The 318 can use the crank & rods from a 340.
Depending on what piston is used and where it sits in the bore, zero deck, down .120, will vary the compression a lot.

“Some miles cam” is huge unknown and your asking us for a reading from a crystal ball. That is ridiculous AF!!!!

It’s output potential is limited by the heads flow ability. But probably hampered by everything else around it.

Sorry buddy, your question is a most joke.

A crystal ball reading with……. Unknown

Carb
Cam
Compression
Type of header
Exhaust
Items bolted on the engine
Ignition kind

At a 323 CID, IF this engine was actually built with some compression with a dome piston and the heads were very well ported, and headers that have a proper sizing to them, at a well built level of 1.4 hp per cube (which would be very good for an average guy in his garage) would equal around 450 hp.
 
So are those 70 340's forged pieces? Also I'm confirming the actual piston diameter/Type. Going to get the cyl head casting number to be sure. Going to see it on Weds. The owner will go see for me in the meantime. He did not make up this combination.
 
Did you skip your meds? Noone said anything about it being a 340. At least I only got a 1 page rant instead of your usual 10 page dissertation on your POS..
 
So it's basically a stronger assy than stock with some 2.02 valves? Possiblly modded to bring up compression ;}
 
A 318 - .030 or not can be a potent engine if you can get a hood compression ratio to work with the cam your intending to use. That Torker intake….. Is it a Torker or a Torker II 340?
There very different intakes. Consider there rpm band another 300-500 more rpm on the small engine.

Your better off IMO, with a modified Offenhouser or Holley Strip Dominator. An M1 single would also be very good.
However this is closer to a race build with those intakes.

You can’t beat a Edelbrock RPM
 
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66fs said:
All SBM have forged rods, most 340's had forged cranks. Who knows what is in that engine. Head castings?
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A lot of 318s had forged cranks. There's no difference in the stroke from 318 to 340, so it's still a 318.
 
mario03srt said:
All,

that has 70 340 internals and heads in a 70 318 +.030 motor.
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Well, I took what I read at face value and thought someone may not know the math and could be in the middle of being taking for a ride by a BS’er scumb bay of a human screwing him out of his money. Seen that before!

So let’s refresh! Internals are;

Crank, rods, pistons $ rings, oil pump and bearings, camshaft, etc…. Those are he main things.

So - ……. How do I know Mario knows?
I’m a Po-boy that never could afford a crystal ball. Sorry.
mario03srt said:
It also has a 340 torker, some mild cam and headers.
Click to expand...
A 340 intake, and unknown cam and headers.
More mystery…
mario03srt said:
What exactly kind of brew is this and what is it's output potential?
Click to expand...
Ask RRR if he had his crystal ball repaired. LMAO!
mario03srt said:
What kind of comp ratio are we talking and cubic inches?
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Not enough info to guess Marion.
If my reply seemed like I’m talking to you like your stupid, don’t be bothered thinking that way. However, someday someone somewhere will read this post and n something that I don’t know if you know but they now will know.
 
66fs said:
All SBM have forged rods, most 340's had forged cranks. Who knows what is in that engine. Head castings?
Click to expand...
He seems to be under the impression the heads somehow change the displacement of the engine?
 
Are you just going to run it as is?
Will you go to the track?
Is this up for being rebuilt?
What is the desire and end goal?
 
mario03srt said:
Did you skip your meds? Noone said anything about it being a 340. At least I only got a 1 page rant instead of your usual 10 page dissertation on your POS..
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Ummm what? You asked questions based on limited info and we're giving you the best answers we can and you want to get smartass? OK. I'm done.
 
RustyRatRod said:
Ummm what? You asked questions based on limited info and we're giving you the best answers we can and you want to get smartass? OK. I'm done.
Click to expand...
Probably a reply for me but you qualify as well since taking a WAG at a mystery motor that has some type of header and a mystery Torker intake seems to be more than enough info for the questioner of no clue.

DANM YOU RRR, get your crystal ball fixed already!!!
:rofl:
 
Seen a bunch of guys over the years take and lower compression with 340 heads and over cam it to have a great sounding car as slow as could be.
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Good compression 318 Pistons are not cheap.
318/340 same stroke. 340 heads are not going to make the 318 into a 340.
 
@340six Humbug!

However…. Hummmmmmmmm
(Edit - correction on values)

5E16D057-FAF5-4395-9547-A3EB5870446A.png
 
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So the answer would be.............323 cubes..........possible very low compression, better crank (good for 5-7 psi?), could possibly be bored to have a 340 piston, if not would require decking and/or some upgraded pistions to run well increase compression. Better flowing head than a 318 stock piece with 2.02/1.65 valves.

Is this recommended other than the comp concerns?

Not asking for hp estimates, usage projections, convertor sizing, DCR, etc, etc, etc.

It is what it is. It in the car. Here is a photo. Basic SBM. Some may be able to id the head, not me. That will happen Wed's and I'll have a comp gage in hand.

318_340.JPEG
 
mario03srt said:
So the answer would be.............323 cubes..........possible very low compression, better crank (good for 5-7 psi?), could possible bored to have a 340 piston, if not would require decking and/or some upgraded pistions to run well. Better flowing head than a 318 stock piece with 2.02/1.65 valves.

Is this recommended other than the comp concerns?

Not asking for hp estimates, usage projections, convertor sizing, DCR, etc, etc, etc.

It is what it is. It in the car. Here is a photo. Basic SBM. Some may be able to id the head, not me. That will happen Wed's and I'll have a comp gage in hand.

View attachment 1715999452
Click to expand...

Bottom line is if you like the car, and think it is worth the money then buy it. Just price it as it sits with a 318 engine.
 
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