Are 340’s rare

-
33IMP said:
Sure. If a 340 shortblock is $2000 (I'm assuming, I've never owned any small block except for the two barrel 273 from my 67 barracuda. I own more 90 year old straight eights than smallblocks!) I would MUCH rather have a $100 318 shortblock bore it .030, and put a scat stroker kit in it... and probably still have less in it than a 340.
And, anything you can put on top of a 340 short, you can put on a 318/392 and get same or better result.
Click to expand...
A 340 short block, equivalently built, would probably be a $500-1000 premium compared to a 318 or 360 based engine. The $2k is overblown.

Ironically a 273 probably would cost more because of the specialty pistons required.
 
Mean416 said:
A 340 short block, equivalently built, would probably be a $500-1000 premium compared to a 318 or 360 based engine. The $2k is overblown.

Ironically a 273 probably would cost more because of the specialty pistons required.
Click to expand...
$227 difference between Egge L2222 for 273 and KB243's for 340. Everything else should be close to the same. (rings, bearings, and gaskets)
Machine work is the same. Your 273 might cost less up front. 273's are cheap to free. 340's are $200-$1000 or more.
 
Mean416 said:
A 340 short block, equivalently built, would probably be a $500-1000 premium compared to a 318 or 360 based engine. The $2k is overblown.

Ironically a 273 probably would cost more because of the specialty pistons required.
Click to expand...
Fair enough, I have never priced 340 stuff.
I would rather build a $2000 392, than a $1000 340
First choice? A 360 roller block stroked to 408, over ANY equivalent build 340.
(That statement does NOT include a 416, that's not a 340 anymore)
 
33IMP said:
Fair enough, I have never priced 340 stuff.
I would rather build a $2000 392, than a $1000 340
First choice? A 360 roller block stroked to 408, over ANY equivalent build 340.
(That statement does NOT include a 416, that's not a 340 anymore)
Click to expand...

And the 392 isn’t a 318 any more.
 
340sFastback said:
Yeah forget about 318 same stroke as a 340 and bore only marginally smaller then a 340. But because they originally had choke heads, low compression, single exhaust they are boat anchors garbage should be junked. They are not suitable starting points ect. And like I said, you can not reason with those ppl. They usually have no clue about building a performance engine, no amount of reasoning or rational thinking, 318s are junk, must be a 340 to be a performance engine.
Click to expand...

“Marginally smaller bore than a 340”
False, not remotely true.
 
Be careful what you wish for. The 408 may not be what you think you want. I have a friend with a 396 camaro and a 408 dart. Both engines are very similarly prepped and geared. Now he raced his cars numerous times against each other and said the Dart always beats the Camaro off the line but by 80 mph the 396 passes and walks away from the over square 408 Dart.The 396 with 3.75 stroke just flat out revs quicker. The 408 certainly makes more torque if that's what you want and may be better suited to a heavy vehicle. The Dart had 3.23 and the Camaro had 3.31 gears.
 
I love 340s i would keep it and use it someday, you will not be disappointed. and you don't need a 4 inch arm, they are overrated in my opinion.
 
ir3333 said:
Be careful what you wish for. The 408 may not be what you think you want. I have a friend with a 396 camaro and a 408 dart. Both engines are very similarly prepped and geared. Now he raced his cars numerous times against each other and said the Dart always beats the Camaro off the line but by 80 mph the 396 passes and walks away from the over square 408 Dart.The 396 with 3.75 stroke just flat out revs quicker. The 408 certainly makes more torque if that's what you want and may be better suited to a heavy vehicle. The Dart had 3.23 and the Camaro had 3.31 gears.
Click to expand...

The 408 is about as square as you can get. Saying it’s over square isn’t really the fact. Somewhere on this thread I posted the bore to stroke ratio of all of these engines.
 
ir3333 said:
Dart always beats the Camaro off the line but by 80 mph the 396 passes and walks away from the over square 408 Dart.The 396 with 3.75 stroke just flat out revs quicker.
Click to expand...
This is what I would expect.
340 rare? Don't know I've never looked for one.
I'll take a bigger bore engine every time.
 
ir3333 said:
Be careful what you wish for. The 408 may not be what you think you want. I have a friend with a 396 camaro and a 408 dart. Both engines are very similarly prepped and geared. Now he raced his cars numerous times against each other and said the Dart always beats the Camaro off the line but by 80 mph the 396 passes and walks away from the over square 408 Dart.The 396 with 3.75 stroke just flat out revs quicker. The 408 certainly makes more torque if that's what you want and may be better suited to a heavy vehicle. The Dart had 3.23 and the Camaro had 3.31 gears.
Click to expand...


Lol. You can’t just compare two completely different cars like that. Does that 396 want to race my 408.
 
I'm sure you could make changes to either one to "one up the other" He just said they had identical cams, same compression and were built with nearly identical specs. I think he was pretty disappointed...he is a Mopar guy. It would never matter to me because i don't race. As i said earlier i don't care if your 408 has 100 more HP than my 340. I still don't want a 360 or 408.
These posts always turn into a "my engines more powerful than yours" competition.
 
ir3333 said:
Be careful what you wish for. The 408 may not be what you think you want. I have a friend with a 396 camaro and a 408 dart. Both engines are very similarly prepped and geared. Now he raced his cars numerous times against each other and said the Dart always beats the Camaro off the line but by 80 mph the 396 passes and walks away from the over square 408 Dart.The 396 with 3.75 stroke just flat out revs quicker. The 408 certainly makes more torque if that's what you want and may be better suited to a heavy vehicle. The Dart had 3.23 and the Camaro had 3.31 gears.
Click to expand...
My 414 revs way way way faster then my stock 340 ever dreamed of. Not sure what all going on with your buddies Dart but my car pulls hard as hell over 80 mph. Over 80 is when its most impressive compared to the lower speeds.
 
B3422w5 said:
“Marginally smaller bore than a 340”
False, not remotely true.
Click to expand...
Yeah, you are 100 percent right, the 340s are a whole .130 inch larger bore then 318s. Not remotely true, yep, thanks for that correction, your the man.

PXL_20240330_015133014.jpg
 
Last edited:
While 340s are not rare, they are valuable. They were made well past just six years, too. You have to include boats and over the counter parts sales with warranty engines and blocks and from Mopar performance as well. Both of those numbers are probably difficult to track, so there's no telling how many total were actually made, but rest assured, it's well beyond what came in cars.
 
Last edited:
340sFastback said:
Yeah, you are 100 percent right, the 340s are a whole . 049 inch larger bore then 318s. Not remotely true, yep, thanks for that correction, your the man.

View attachment 1716228870
Click to expand...

I'll say it again, it's also about bore to stroke ratio.

My math says 4.04 minus 3.910 is .130 and not the .049 you calculated.

That's over an EIGHTH of an INCH bigger bore. That's a big thing.

I'll take RPM over stoke length any day.
 
ir3333 said:
Be careful what you wish for. The 408 may not be what you think you want. I have a friend with a 396 camaro and a 408 dart. Both engines are very similarly prepped and geared. Now he raced his cars numerous times against each other and said the Dart always beats
Click to expand...

ir3333 said:
the Camaro off the line but by 80 mph the 396 passes and walks away from the over square 408 Dart.The 396 with 3.75 stroke just flat out revs quicker. The 408 certainly makes more torque if that's what you want and may be better suited to a heavy vehicle. The Dart had 3.23 and the Camaro had 3.31 gears.
Click to expand...
If it's a big port 396, it's probably got 30-40% more head flow than your typical 408 head. Even a stock oval port bbc head will flow 50 cfm more than a stock 440 head. The peanut port bbc that all the chevy guys laugh at outflows a 440 head. Flow restricted 408s make great torque, great for driving around with an auto and mild gear. To run with a bbc, a 408 will need a BUNCH of good heads and headwork. (Talking basic street car, not racecars, John C, lol)
Edit: how do you KNOW its a 396/402? I tell everybody mine is "a hundred over 396". It's not my fault if they think 421, instead of 496. Sixty over 427s rev even better than 396s!
 
Last edited:
Newbomb Turk said:
I'll say it again, it's also about bore to stroke ratio.

My math says 4.04 minus 3.910 is .130 and not the .049 you calculated.

That's over an EIGHTH of an INCH bigger bore. That's a big thing.

I'll take RPM over stoke length any day.
Click to expand...
That's because horsepower keeps climbing with RPM. That is, until parts are layin on the ground. lol
 
Newbomb Turk said:
I'll say it again, it's also about bore to stroke ratio.

My math says 4.04 minus 3.910 is .130 and not the .049 you calculated.

That's over an EIGHTH of an INCH bigger bore. That's a big thing.

I'll take RPM over stoke length any day.
Click to expand...
I'll take stroke length over rpm, any day.
 
Newbomb Turk said:
I'll say it again, it's also about bore to stroke ratio.

My math says 4.04 minus 3.910 is .130 and not the .049 you calculated.

That's over an EIGHTH of an INCH bigger bore. That's a big thing.

I'll take RPM over stoke length any day.
Click to expand...
You are right 1/8 is a pretty big difference.
 
340sFastback said:
Yeah, you are 100 percent right, the 340s are a whole . 049 inch larger bore then 318s. Not remotely true, yep, thanks for that correction, your the man.

View attachment 1716228870
Click to expand...

340sFastback said:
Yeah, you are 100 percent right, the 340s are a whole . 049 inch larger bore then 318s. Not remotely true, yep, thanks for that correction, your the man.

View attachment 1716228870
Click to expand...

It’s more like 130. It’s a ton, otherwise I wouldn’t have pointed it out to you.
I had a virgin X block bored from its virgin 318 size bore out to 4.07 to go to 416 cubes. You wouldn’t believe how much weight that removed from the block. A ton of iron.
 
Yeah well rpm ain't everything to a streeter. example;
7500 in first gear(TF) with 3.23s comes to 68mph. Did I say still in First gear?
With a power-peak near 7000, what cam do you run, and how's that gonna run in Drive at 30 mph?
No thanks.
I'll take the 408, or 388 (4.04 x 3.79), or even an HO367, with a power-peak around 5400 give or take.
But I gotta say this;
a super-Hi-Compression 340, with a 318 cam, makes a chitload of Bottom-End torque, which is just right for a streeter with 3.23s, or even, a lil less.

I used to get so much flack for having a 360-based small-block. Since it's a 4.04 x 3.58, I started calling it a stroked 340, and that was the end of the criticisms.
 
You must log in or register to reply here.
-

Back
Top