Previous Thread
Next Thread
Print Thread
Page 1 of 2 1 2
360 to 408, or 340 to 410? #1794618
04/02/15 12:52 AM
04/02/15 12:52 AM
Joined: Oct 2007
Posts: 2,808
Wisconsin
wkroncke17 Offline OP
master
wkroncke17  Offline OP
master

Joined: Oct 2007
Posts: 2,808
Wisconsin
I have a '72 340, and a '73 360.
I would like to build a stroker motor - is there any advantage to building the 360 into the 408, or the 340 into a 410?
Engine will be in a street/strip Demon, hyd cam (maybe roller) auto trans.
Thanks ahead of time!!

Re: 360 to 408, or 340 to 410? [Re: wkroncke17] #1794619
04/02/15 12:58 AM
04/02/15 12:58 AM
Joined: Jun 2003
Posts: 52,972
Romeo MI
MR_P_BODY Offline
Master
MR_P_BODY  Offline
Master

Joined: Jun 2003
Posts: 52,972
Romeo MI
The bigger bore helps unshroud the valves but if your
using a 2.02 valve it doesnt matter... I use 340
blocks because all my stuff has the small mains...
I went with a 416ci for my street/strip

Re: 360 to 408, or 340 to 410? [Re: wkroncke17] #1794620
04/02/15 12:59 AM
04/02/15 12:59 AM
Joined: Oct 2003
Posts: 7,506
Az
Crizila Offline
master
Crizila  Offline
master

Joined: Oct 2003
Posts: 7,506
Az
The 340 block is the rarer of the two, so I would keep the 340 and do the 360. - looking at it from a financial standpoint.


Fastest 300
Re: 360 to 408, or 340 to 410? [Re: Crizila] #1794621
04/02/15 01:02 AM
04/02/15 01:02 AM
Joined: Jun 2003
Posts: 52,972
Romeo MI
MR_P_BODY Offline
Master
MR_P_BODY  Offline
Master

Joined: Jun 2003
Posts: 52,972
Romeo MI
Quote:

The 340 block is the rarer of the two, so I would keep the 340 and do the 360. - looking at it from a financial standpoint.




Save it for what... if ya got it.. use it
EDIT
If he wants to sell the 340 block I'll buy it

Last edited by MR_P_BODY; 04/02/15 01:03 AM.
Re: 360 to 408, or 340 to 410? [Re: MR_P_BODY] #1794622
04/02/15 01:19 AM
04/02/15 01:19 AM
Joined: Oct 2007
Posts: 2,808
Wisconsin
wkroncke17 Offline OP
master
wkroncke17  Offline OP
master

Joined: Oct 2007
Posts: 2,808
Wisconsin
Quote:

Quote:

The 340 block is the rarer of the two, so I would keep the 340 and do the 360. - looking at it from a financial standpoint.




Save it for what... if ya got it.. use it
EDIT
If he wants to sell the 340 block I'll buy it





Haha! Sorry Mike......I will use the 340 if it's the better choice?
So don't go telling me the 360 is better just to get me to sell you the 340.
I'll be using the stock heads,,,,,,stock '72 heads have 1.88 intake, correct?
Might get Eddys at best.

Wally.

Re: 360 to 408, or 340 to 410? [Re: wkroncke17] #1794623
04/02/15 01:26 AM
04/02/15 01:26 AM
Joined: Jun 2003
Posts: 52,972
Romeo MI
MR_P_BODY Offline
Master
MR_P_BODY  Offline
Master

Joined: Jun 2003
Posts: 52,972
Romeo MI
Quote:

Quote:

Quote:

The 340 block is the rarer of the two, so I would keep the 340 and do the 360. - looking at it from a financial standpoint.




Save it for what... if ya got it.. use it
EDIT
If he wants to sell the 340 block I'll buy it





Haha! Sorry Mike......I will use the 340 if it's the better choice?
So don't go telling me the 360 is better just to get me to sell you the 340.
I'll be using the stock heads,,,,,,stock '72 heads have 1.88 intake, correct?
Might get Eddys at best.

Wally.




Really.. if your using stock type heads it wont matter..
its gonna be the same stroke so the torque will be
very close either way... if you were racing it then
yes the 340 is better.. bigger bore and smaller mains

Re: 360 to 408, or 340 to 410? [Re: MR_P_BODY] #1794624
04/02/15 06:26 AM
04/02/15 06:26 AM
Joined: Jul 2009
Posts: 413
Norway (old world)
Oyvind Mopar Offline
mopar
Oyvind Mopar  Offline
mopar

Joined: Jul 2009
Posts: 413
Norway (old world)
If you choose the cast crank stroker the 360 bigger main block is definitely better. But it is no good for racing!

Re: 360 to 408, or 340 to 410? [Re: MR_P_BODY] #1794625
04/02/15 11:07 AM
04/02/15 11:07 AM
Joined: Oct 2007
Posts: 2,808
Wisconsin
wkroncke17 Offline OP
master
wkroncke17  Offline OP
master

Joined: Oct 2007
Posts: 2,808
Wisconsin
Quote:

The bigger bore helps unshroud the valves but if your
using a 2.02 valve it doesnt matter... I use 340
blocks because all my stuff has the small mains...
I went with a 416ci for my street/strip





Can you explain "Unshroud the Valves?"
Also - the 340 has smaller mains - less resistance I assume - is a cast crank not good for this?
I plan on 10:1 comp at the most??
Thank you very much guys!!

Wally.

Re: 360 to 408, or 340 to 410? [Re: wkroncke17] #1794626
04/02/15 11:26 AM
04/02/15 11:26 AM
Joined: Jun 2003
Posts: 52,972
Romeo MI
MR_P_BODY Offline
Master
MR_P_BODY  Offline
Master

Joined: Jun 2003
Posts: 52,972
Romeo MI
Quote:

Quote:

The bigger bore helps unshroud the valves but if your
using a 2.02 valve it doesnt matter... I use 340
blocks because all my stuff has the small mains...
I went with a 416ci for my street/strip





Can you explain "Unshroud the Valves?"
Also - the 340 has smaller mains - less resistance I assume - is a cast crank not good for this?
I plan on 10:1 comp at the most??
Thank you very much guys!!

Wally.




As the air is coming in it hits the bore on half the
valve
so the bigger bore helps ... you got the idea of
the smaller mains

Re: 360 to 408, or 340 to 410? [Re: wkroncke17] #1794627
04/02/15 11:47 AM
04/02/15 11:47 AM
Joined: Oct 2003
Posts: 11,684
W. Kentucky
justinp61 Offline
I Live Here
justinp61  Offline
I Live Here

Joined: Oct 2003
Posts: 11,684
W. Kentucky
Use which ever one you want, for what your doing there won't be a nickel's worth of difference. My 408 made around 550 hp, there is no way I would've noticed any difference if it had been built on a 340 block. Build it and enjoy, 4" motors are a hoot.

Re: 360 to 408, or 340 to 410? [Re: justinp61] #1794628
04/02/15 12:26 PM
04/02/15 12:26 PM
Joined: Oct 2003
Posts: 7,506
Az
Crizila Offline
master
Crizila  Offline
master

Joined: Oct 2003
Posts: 7,506
Az
Quote:

Use which ever one you want, for what your doing there won't be a nickel's worth of difference. My 408 made around 550 hp, there is no way I would've noticed any difference if it had been built on a 340 block. Build it and enjoy, 4" motors are a hoot.


For what he wants to do, performance difference based on bore size and crank journal size, just about un measureable. Does anyone know why Mopar went from a 340 block to a 360 block?


Fastest 300
Re: 360 to 408, or 340 to 410? [Re: Crizila] #1794629
04/02/15 12:59 PM
04/02/15 12:59 PM
Joined: Jan 2003
Posts: 9,872
Weddington, N.C.
Streetwize Offline
master
Streetwize  Offline
master

Joined: Jan 2003
Posts: 9,872
Weddington, N.C.
If you have an uncut 340 and the bores clean-up at .020 you wind up with a standard 4.06" bore which has lots and lots more piston and ring pack choices readily available. Plus you get to save the block for additional incremental bores later...If I can I go 4.06 I will and I'll save for a possible need for 4.07 down the road.

Valve shrouding is IMO more of a concern on Big block Mopar Wedges than on small blocks due the SB superior valve angle, on-center valve/bore placement, the limiting factor on SBM's is generally port cross section and pushrod pinch shrouding.

all else being equal a 340 stroker will have a bit less frictional losses at the mains due to its' smaller bearing diameter....a 360 will also be a bit heavier due to those thicker crank mains (steel is heavier than cast iron)

360s are a lot more plentiful though

As for why mopar went to a 360 instead of just a 4" bore 318 block, I suspect cost cutting with the longer 3.58 stroke allowed for cheaper but still strong cast crank production and external balancing saving millions ofver the mass production multi-year run of the engine. As evidence of that, (to my knowledge) there was never a steel or internally balanced 360 made. The 360 was also intended as a gap bridger for trucks and the big C bodys between the 318 and the (was 383, now 400).

Last edited by Streetwize; 04/02/15 01:13 PM.

WIZE

World's Quickest Diahatsu Rocky (??) 414" Stroker Small block Mopar Powered. 10.84 @ 123...and gettin' quicker!

https://www.youtube.com/watch?v=-mWzLma3YGI

In Car:

https://www.youtube.com/watch?v=PjXcf95e6v0
Re: 360 to 408, or 340 to 410? [Re: Streetwize] #1794630
04/02/15 01:18 PM
04/02/15 01:18 PM
Joined: Jan 2005
Posts: 12,419
Kalispell Mt.
H
HotRodDave Offline
I Live Here
HotRodDave  Offline
I Live Here
H

Joined: Jan 2005
Posts: 12,419
Kalispell Mt.
Selling the 340 could pay for some of the machine work on the 360 block or a little professional help on porting the heads or some other upgrade that will be more beneficial than a .040 bore and smaller mains. I sold all my 340s I had been hoarding and am mostly building 360 magnum blocks.


I am not causing global warming, I am just trying to hold off a impending Ice Age!



Re: 360 to 408, or 340 to 410? [Re: Streetwize] #1794631
04/02/15 02:24 PM
04/02/15 02:24 PM
Joined: Oct 2003
Posts: 7,506
Az
Crizila Offline
master
Crizila  Offline
master

Joined: Oct 2003
Posts: 7,506
Az
Quote:

If you have an uncut 340 and the bores clean-up at .020 you wind up with a standard 4.06" bore which has lots and lots more piston and ring pack choices readily available. Plus you get to save the block for additional incremental bores later...If I can I go 4.06 I will and I'll save for a possible need for 4.07 down the road.

Valve shrouding is IMO more of a concern on Big block Mopar Wedges than on small blocks due the SB superior valve angle, on-center valve/bore placement, the limiting factor on SBM's is generally port cross section and pushrod pinch shrouding.

all else being equal a 340 stroker will have a bit less frictional losses at the mains due to its' smaller bearing diameter....a 360 will also be a bit heavier due to those thicker crank mains (steel is heavier than cast iron)

360s are a lot more plentiful though

As for why mopar went to a 360 instead of just a 4" bore 318 block, I suspect cost cutting with the longer 3.58 stroke allowed for cheaper but still strong cast crank production and external balancing saving millions ofver the mass production multi-year run of the engine. As evidence of that, (to my knowledge) there was never a steel or internally balanced 360 made. The 360 was also intended as a gap bridger for trucks and the big C bodys between the 318 and the (was 383, now 400).


also thought there was a SCCA / NASCAR cubic inch rule change involved there. The 340 was always touted as the "performance engine", mostly because of when it came on board (1970)and of course the performance options available. When the 360 showed up ( 1971 - with a 2-barrel only ) the performance party was on the way out. On the market, that 340 is probably worth 2-3 times what the 360 is worth.


Fastest 300
Re: 360 to 408, or 340 to 410? [Re: Crizila] #1794632
04/02/15 02:34 PM
04/02/15 02:34 PM
Joined: Mar 2007
Posts: 12,008
Finally a HUSKER again
Moparnut426 Offline
I Live Here
Moparnut426  Offline
I Live Here

Joined: Mar 2007
Posts: 12,008
Finally a HUSKER again
For your application Im thinking you wont see a difference. But Mikes right, smaller mains, less resistance, bigger bore, unshrouded air charge.

I used a 360/408. I hade a block, I used it, I would have done same thing VS a 340 block but I didn't have one Id trust.

So.... 408 for me only because its what I had. I have a K1 crank, and Indybrock heads. 602" solid roller, and I LOVE IT!!!

Its really fun in a light A body.

Re: 360 to 408, or 340 to 410? [Re: Moparnut426] #1794633
04/02/15 03:31 PM
04/02/15 03:31 PM
Joined: Feb 2004
Posts: 6,257
acworth / N. georgia - south e...
cheapstreetdustr Offline
master
cheapstreetdustr  Offline
master

Joined: Feb 2004
Posts: 6,257
acworth / N. georgia - south e...
I would look at it this way...
start shopping for a crank.. look for the best deal.. and depending if its a large main or small main that would dictate which block you use..
yr back I had a 340 block I sold off to use the money to build a 385 cui class rule engine.
and planned on using a early 360 block.
as soon as I sold off the 340 block all I could find deals on for cranks was for 340 mains..
some killer deal on a k1 3.79 stroke crank came available but It was a 340 main..
I didn't have the 340 anymore so couldn't take advantage of the killer crank deal.
shop for a crank first ....that will dictate which block to use.
that's my


365" Iron J heads,,3480lbs best 1.39 60ft on SS springs.10.54,124 mph ...6.67 1/8th et.average 60fts 1.46 w/ small cam &.063 no2 pill tagged & insured
[image][/image]
Re: 360 to 408, or 340 to 410? [Re: cheapstreetdustr] #1794634
04/02/15 04:35 PM
04/02/15 04:35 PM
Joined: Jan 2003
Posts: 9,872
Weddington, N.C.
Streetwize Offline
master
Streetwize  Offline
master

Joined: Jan 2003
Posts: 9,872
Weddington, N.C.


Cheeps got it right.

For the record, I have one of each a 414" 340 and a 440" 360, I just call them the Orange one and the blue one


WIZE

World's Quickest Diahatsu Rocky (??) 414" Stroker Small block Mopar Powered. 10.84 @ 123...and gettin' quicker!

https://www.youtube.com/watch?v=-mWzLma3YGI

In Car:

https://www.youtube.com/watch?v=PjXcf95e6v0
Re: 360 to 408, or 340 to 410? [Re: cheapstreetdustr] #1794635
04/02/15 04:37 PM
04/02/15 04:37 PM
Joined: Oct 2003
Posts: 11,684
W. Kentucky
justinp61 Offline
I Live Here
justinp61  Offline
I Live Here

Joined: Oct 2003
Posts: 11,684
W. Kentucky
It seems every time a 340-360 question comes up the bore and main diameter come up also. I'd like to see how the nhra factors say a 73 340 Duster against a 74 360 Duster and what et's the two engines are running in these cars in class legal stock trim. I think the 73 verse a 74 is the most fair comparison.

Re: 360 to 408, or 340 to 410? [Re: cheapstreetdustr] #1794636
04/02/15 05:51 PM
04/02/15 05:51 PM
Joined: Oct 2003
Posts: 7,506
Az
Crizila Offline
master
Crizila  Offline
master

Joined: Oct 2003
Posts: 7,506
Az
Quote:

I would look at it this way...
start shopping for a crank.. look for the best deal.. and depending if its a large main or small main that would dictate which block you use..
yr back I had a 340 block I sold off to use the money to build a 385 cui class rule engine.
and planned on using a early 360 block.
as soon as I sold off the 340 block all I could find deals on for cranks was for 340 mains..
some killer deal on a k1 3.79 stroke crank came available but It was a 340 main..
I didn't have the 340 anymore so couldn't take advantage of the killer crank deal.
shop for a crank first ....that will dictate which block to use.
that's my


Stroker kit prices for both engines is almost identical ( 360 is actually a little less - Hughes engines prices ). Shopping for used stroker cranks will show no advantage ( one engine over the other) either. Selling the 340 and building the 360 will definitely net you a $ advantage for your shopping fun. Did I mention the smaller bore of the 360 will have less friction than the larger bore 340. The larger main journal on the 360 will have more journal overlap making it stiffer. Since none of this is much of a concern with the OP's application and very difficult to measure, it gets down to $ - which is definitely measureable - IMO. Did I mention that I have a stock journal size ( E58 motor ) 360 crank for sale?


Fastest 300
Re: 360 to 408, or 340 to 410? [Re: Crizila] #1794637
04/02/15 11:20 PM
04/02/15 11:20 PM
Joined: Oct 2007
Posts: 2,808
Wisconsin
wkroncke17 Offline OP
master
wkroncke17  Offline OP
master

Joined: Oct 2007
Posts: 2,808
Wisconsin
Thank you all for the very useful info.
I think i will look for the best deal.
Ive read somewhere on here that the best prices are at a place called Bloomers or something??

Thanks again all, i greatly appreciate it!!

Re: 360 to 408, or 340 to 410? [Re: wkroncke17] #1794638
04/03/15 12:09 AM
04/03/15 12:09 AM
Joined: Nov 2004
Posts: 1,745
Maryland
340_Dart Offline
top fuel
340_Dart  Offline
top fuel

Joined: Nov 2004
Posts: 1,745
Maryland
I think it all comes down to personal preference. I have one of each, and I have decided that if I build anymore stock block strokers, they will be 360 main.

Definitely get with Rod Bloomer, BPE on here. His stuff is top notch!

Re: 360 to 408, or 340 to 410? [Re: 340_Dart] #1794639
04/03/15 12:05 PM
04/03/15 12:05 PM
Joined: Oct 2007
Posts: 2,808
Wisconsin
wkroncke17 Offline OP
master
wkroncke17  Offline OP
master

Joined: Oct 2007
Posts: 2,808
Wisconsin
Quote:

I think it all comes down to personal preference. I have one of each, and I have decided that if I build anymore stock block strokers, they will be 360 main.

Definitely get with Rod Bloomer, BPE on here. His stuff is top notch!




What is the "main" reason you would build the 360 over a 340?
I assume its availability.....
Does anyone know Rod @ BPE's handle here on Moparts?

Again, thank you very much everyone!

Wally.

Re: 360 to 408, or 340 to 410? [Re: wkroncke17] #1794640
04/03/15 12:16 PM
04/03/15 12:16 PM
Joined: Jan 2003
Posts: 9,872
Weddington, N.C.
Streetwize Offline
master
Streetwize  Offline
master

Joined: Jan 2003
Posts: 9,872
Weddington, N.C.
I have one of Rods 4.25" BPE Cranks in my 440" w2 360, great guy, Highly recommended!


WIZE

World's Quickest Diahatsu Rocky (??) 414" Stroker Small block Mopar Powered. 10.84 @ 123...and gettin' quicker!

https://www.youtube.com/watch?v=-mWzLma3YGI

In Car:

https://www.youtube.com/watch?v=PjXcf95e6v0
Re: 360 to 408, or 340 to 410? [Re: Streetwize] #1794641
04/03/15 12:25 PM
04/03/15 12:25 PM
Joined: Nov 2004
Posts: 1,745
Maryland
340_Dart Offline
top fuel
340_Dart  Offline
top fuel

Joined: Nov 2004
Posts: 1,745
Maryland
Yes, availability is why I chose 360 blocks over the 340. I feel the mains and bore size are minimal in overall power.

Rod goes by BPE on here.

Re: 360 to 408, or 340 to 410? [Re: wkroncke17] #1799032
04/09/15 12:43 AM
04/09/15 12:43 AM
Joined: Aug 2003
Posts: 374
kalamazoo, MI.
VIPERDUST Offline
enthusiast
VIPERDUST  Offline
enthusiast

Joined: Aug 2003
Posts: 374
kalamazoo, MI.
He's on here, Rod Bloomer.

Re: 360 to 408, or 340 to 410? [Re: justinp61] #1800099
04/10/15 10:45 AM
04/10/15 10:45 AM
Joined: Jan 2003
Posts: 402
Dillsburg, PA
M
mrsmallblock Offline
mopar
mrsmallblock  Offline
mopar
M

Joined: Jan 2003
Posts: 402
Dillsburg, PA
Less oil demand with the smaller mains also....

Howard

Page 1 of 2 1 2






Powered by UBB.threads™ PHP Forum Software 7.7.1