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best performance 340 or 360? #1656366 08/08/14 12:55 PM 08/08/14 12:55 PM
Joined: Aug 2006 Posts: 1,349 warfordsburg, PA dirt OP pro stock
dirt OP pro stock Joined: Aug 2006 Posts: 1,349 warfordsburg, PA	i am trying to decide on what motor to install in a dart that will really only get driven on the weekeds for fun. it is an original 340 car and i am leaning to putting a 340 back in but i but i also plan to drive and possibly make a few passes on street night at the strip with it so i want it to run good. i have two motors i am thinking about using. the first is a 1970 , 340 with forged 10.25-1 pistons the second is a 1978 360 with Hypereutectic stock compression pistons. i plan on getting a new cam no matter what motor i build but will keep the pistons that are in them now. i have a set of edelbrock closed chamber heads that i ran on a 360 that i will use . so that would help compression on the 360 and if i used on the 340 i would need to get a thicker head gasket since the pistons pop up .016 out of the block . i have heard people talk about the 360 having more torque because of the stroke being longer and i dont want to build the 340 if it will not at least run as good as the 360. i fugure at this point either motor will cost about the same to build so i may as well build the best one. any advice on this?

Re: best performance 340 or 360? [Re: dirt] #1656367 08/08/14 01:08 PM 08/08/14 01:08 PM
Joined: Jun 2005 Posts: 5,102 Western Md. skicker "The Champ"
skicker "The Champ" Joined: Jun 2005 Posts: 5,102 Western Md.	340 = 3.31 stroke 360 = 3.58 stroke Although the stroke in the 360 is longer the lack of compression would make it run slower than the 340. If you used both short blocks in stock form the 340 would be better. If your going to tweak it a little the aftermarket really supports the 360. I would use the 340 but its your call... ...FAFO...

Re: best performance 340 or 360? [Re: dirt] #1656368 08/08/14 01:56 PM 08/08/14 01:56 PM
Joined: Aug 2003 Posts: 43,123 Bend,OR USA C Cab_Burge I Win
Cab_Burge I Win C Joined: Aug 2003 Posts: 43,123 Bend,OR USA	First thing you need to do is to figure the true mechanical compression ratio on both motors and go from there If the 340 is anywhere near blueprint specs, 11.56 to 1 and the 360 is under that, and above 8.75 to 1, I would use the 360 Mr.Cab Racing and winning with Mopars since 1964. (Old F--t, Huh)

Re: best performance 340 or 360? [Re: Cab_Burge] #1656369 08/08/14 03:04 PM 08/08/14 03:04 PM
Joined: Jan 2003 Posts: 16,376 D dogdays I Live Here
dogdays I Live Here D Joined: Jan 2003 Posts: 16,376	Oh no, not again! R.

Re: best performance 340 or 360? [Re: Cab_Burge] #1656370 08/08/14 03:18 PM 08/08/14 03:18 PM
Joined: May 2003 Posts: 6,560 Downtown Roebuck Ont Twostick Still wishing...
Twostick Still wishing... Joined: May 2003 Posts: 6,560 Downtown Roebuck Ont	No replacement for displacement. Kevin

Re: best performance 340 or 360? [Re: Twostick] #1656371 08/08/14 03:35 PM 08/08/14 03:35 PM
Joined: Aug 2006 Posts: 1,349 warfordsburg, PA dirt OP pro stock
dirt OP pro stock Joined: Aug 2006 Posts: 1,349 warfordsburg, PA	i guess if its debateable as to what motor is the better one , then i probably would be happy with either one if they both make similar power, a couple horse power difference is not going to bother me. if they are within 15 horse power of each outher then i may as well build the 340. since it has a forged crank and forged pistons, seems like it would take more of a beating if i ever decided to hammer on it. would there really be a difference you could feel on the street or see at the drag strip?

Re: best performance 340 or 360? [Re: dirt] #1656372 08/08/14 04:50 PM 08/08/14 04:50 PM
Joined: Jan 2003 Posts: 2,155 Tucson, Arizona clonestocker top fuel
clonestocker top fuel Joined: Jan 2003 Posts: 2,155 Tucson, Arizona	Quote: i guess if its debateable as to what motor is the better one , then i probably would be happy with either one if they both make similar power, a couple horse power difference is not going to bother me. if they are within 15 horse power of each outher then i may as well build the 340. since it has a forged crank and forged pistons, seems like it would take more of a beating if i ever decided to hammer on it. would there really be a difference you could feel on the street or see at the drag strip? The 340 and 360 are two different animals. I've been playing with 360's for years and you can make them run. matt [img] [/img]

Re: best performance 340 or 360? [Re: dirt] #1656373 08/08/14 05:17 PM 08/08/14 05:17 PM
Joined: Jun 2003 Posts: 52,972 Romeo MI MR_P_BODY Master
MR_P_BODY Master Joined: Jun 2003 Posts: 52,972 Romeo MI	Depends on what heads... I'll take the bore any day and make up for the stroke in RPMs... being its a Dart I'd run the 340 but I also want some other factors also... conv and a gear.. I also want to turn it higher than 6000(stock rpm).. valve springs were the weak link in stock 340s... if you have decent heads with over size valves.. I want bore

Re: best performance 340 or 360? [Re: MR_P_BODY] #1656374 08/08/14 05:36 PM 08/08/14 05:36 PM
Joined: Dec 2009 Posts: 20,627 in a cattle trailer down by th... G Guitar Jones Paddle faster! I hear banjo music!
Guitar Jones Paddle faster! I hear banjo music! G Joined: Dec 2009 Posts: 20,627 in a cattle trailer down by th...	I have done both with identical parts and spec's except of course for the bore and stroke. This was my race car though so it had W5 heads and a large flat tappet. I revved the 340 to 8000 and used a converter that was about 500 rpm more stall speed and a 5.13 gear. The 360 used a 4.88 gear and revved to 7200. They ran identical ET's but the 360 left a little harder but wasn't as strong on the top end. The 340 had a great top end charge and I loved that for racing the slower cars. The drawback was the 340 required more valvetrain maintenance from the higher RPMs. "Follow me the wise man said, but he walked behind" '92 D250 Club Cab CTD, 47RH conversion, pump tweaks, injectors, rear disc and hydroboost conversion. '74 W200 Crew Cab 360, NV4500, D44, D60 and NP205 divorced transfer case. Rear disc and hydroboost coming soon! 2019 1500 Long Horn Crew Cab 4WD, 5.7 Hemi.

Re: best performance 340 or 360? [Re: Guitar Jones] #1656375 08/08/14 08:36 PM 08/08/14 08:36 PM
Joined: May 2014 Posts: 108 Socal L littleVAL member
littleVAL member L Joined: May 2014 Posts: 108 Socal	340 is nice because the extra bore size helps the heads flow better. The shorter stroke can allow for more rpm. The 360 I like the extra cubes and torque off the line. Less maintenance because you don't have to beat on it to get the power. The other advantage is if you scatter it there are thousands more everywhere to replace it. One option would be some light aftermarket rods and pistons in 360 and you could give it some r's when you need it. I would build a stroker the costs have come down so much (such as a kit from BPE) it isn't that much more. Last edited by littleVAL; 08/08/14 08:42 PM.

Re: best performance 340 or 360? [Re: littleVAL] #1656376 08/08/14 09:21 PM 08/08/14 09:21 PM
Joined: Apr 2005 Posts: 673 Emmett, Idaho S SuperStockWagon mopar
SuperStockWagon mopar S Joined: Apr 2005 Posts: 673 Emmett, Idaho	Quote: The 360 I like the extra cubes and torque off the line. Less maintenance because you don't have to beat on it to get the power. The other advantage is if you scatter it there are thousands more everywhere to replace it. One option would be some light aftermarket rods and pistons in 360 and you could give it some r's when you need it. I would build a stroker the costs have come down so much (such as a kit from BPE) it isn't that much more. This NHRA Stock/SuperStock Class Racing..Engineered Muscle In Motion!

Re: best performance 340 or 360? [Re: SuperStockWagon] #1656377 08/09/14 12:00 PM 08/09/14 12:00 PM
Joined: Jun 2007 Posts: 1,161 Mississippi M Mr. T super stock
Mr. T super stock M Joined: Jun 2007 Posts: 1,161 Mississippi	I would not worry about the 360 taking a beating. The 360 in my Dart was built 19 years ago. The only thing replaced internally since then was new valve springs either 2 or 3 years ago. The engine never turns over 5,800 r.p.m., but it has held up well as a bracket racer.

Re: best performance 340 or 360? [Re: SuperStockWagon] #1656378 08/09/14 12:08 PM 08/09/14 12:08 PM
Joined: Oct 2003 Posts: 7,506 Az Crizila master
Crizila master Joined: Oct 2003 Posts: 7,506 Az	Quote: Quote: The 360 I like the extra cubes and torque off the line. Less maintenance because you don't have to beat on it to get the power. The other advantage is if you scatter it there are thousands more everywhere to replace it. One option would be some light aftermarket rods and pistons in 360 and you could give it some r's when you need it. I would build a stroker the costs have come down so much (such as a kit from BPE) it isn't that much more. This Save the 340 and build the 360. Fastest 300

Re: best performance 340 or 360? [Re: Crizila] #1656379 08/09/14 12:18 PM 08/09/14 12:18 PM
Joined: Jun 2003 Posts: 52,972 Romeo MI MR_P_BODY Master
MR_P_BODY Master Joined: Jun 2003 Posts: 52,972 Romeo MI	Quote: Quote: Quote: The 360 I like the extra cubes and torque off the line. Less maintenance because you don't have to beat on it to get the power. The other advantage is if you scatter it there are thousands more everywhere to replace it. One option would be some light aftermarket rods and pistons in 360 and you could give it some r's when you need it. I would build a stroker the costs have come down so much (such as a kit from BPE) it isn't that much more. This Save the 340 and build the 360. Yes do that... but sell me the 340 block... which engine made more HP... seems most everyone on this site isnt into RPM.. hp is measured in rpm and if you put more rpms in that minute you make more hp... I'll buy the 340 block.. I'm starting to run low on them

Re: best performance 340 or 360? [Re: MR_P_BODY] #1656380 08/09/14 02:06 PM 08/09/14 02:06 PM
Joined: Sep 2004 Posts: 6,906 IL, Aurora A ademon master
ademon master A Joined: Sep 2004 Posts: 6,906 IL, Aurora	Quote: Quote: Quote: Quote: The 360 I like the extra cubes and torque off the line. Less maintenance because you don't have to beat on it to get the power. The other advantage is if you scatter it there are thousands more everywhere to replace it. One option would be some light aftermarket rods and pistons in 360 and you could give it some r's when you need it. I would build a stroker the costs have come down so much (such as a kit from BPE) it isn't that much more. This Save the 340 and build the 360. Yes do that... but sell me the 340 block... which engine made more HP... seems most everyone on this site isnt into RPM.. hp is measured in rpm and if you put more rpms in that minute you make more hp... I'll buy the 340 block.. I'm starting to run low on them when they were stock we would spin the 340's to 6'000 +. With all the nice parts these 340/360's make power and should be reliable past 7k

Re: best performance 340 or 360? [Re: ademon] #1656381 08/09/14 03:05 PM 08/09/14 03:05 PM
Joined: Feb 2006 Posts: 1,949 land of 10,000______'s B BDS871Cuda top fuel
BDS871Cuda top fuel B Joined: Feb 2006 Posts: 1,949 land of 10,000______'s	I like the idea where you can take a 340 and punch and stroke it to 426 C.I. then fit it in a little Dodge Colt or Plymouth arrow from the 70s and that thing would just rip up the street or strip. Worked for Bob Glidden. Snap your neck, mega G-force launch, is all I want!

Re: best performance 340 or 360? [Re: MR_P_BODY] #1656382 08/09/14 03:39 PM 08/09/14 03:39 PM
Joined: May 2014 Posts: 108 Socal L littleVAL member
littleVAL member L Joined: May 2014 Posts: 108 Socal	It is a street car that is why I think a less aggressive approach is better. Keep the rpms down and the need for repairs down as well. With the added benefit of better (lower) gearing and mileage on the street

Re: best performance 340 or 360? [Re: littleVAL] #1656383 08/09/14 04:06 PM 08/09/14 04:06 PM
Joined: Jun 2003 Posts: 52,972 Romeo MI MR_P_BODY Master
MR_P_BODY Master Joined: Jun 2003 Posts: 52,972 Romeo MI	Quote: It is a street car that is why I think a less aggressive approach is better. Keep the rpms down and the need for repairs down as well. With the added benefit of better (lower) gearing and mileage on the street On my W-9 I spun it to 8200 every pass and it was higher at times... I checked the lash twice a year but never changed it in 5 years.. if he use quality parts he wont touch things for years.. JMO on his set up... he can do what ever floats his boat.. I gave my opinion and the reasons why

Re: best performance 340 or 360? [Re: MR_P_BODY] #1656384 08/09/14 07:33 PM 08/09/14 07:33 PM
Joined: Jan 2003 Posts: 1,436 Oklahoma City OK Cudajon pro stock
Cudajon pro stock Joined: Jan 2003 Posts: 1,436 Oklahoma City OK	Mouthball the 340, build the 360. If its a original 340 car someday you may want to go back stock. That way you can beat the heck outta the 360. JMO http://www.youtube.com/watch?v=4J3K94cRC1c

Re: best performance 340 or 360? [Re: Cudajon] #1656385 08/10/14 11:15 PM 08/10/14 11:15 PM
Joined: Aug 2006 Posts: 1,349 warfordsburg, PA dirt OP pro stock
dirt OP pro stock Joined: Aug 2006 Posts: 1,349 warfordsburg, PA	thanks everyone for the advice. I know the 340 is worth more money but I don't plan to sell it anyway and if the performance of the 360 and 340 is similar, I think I will go with the 340. partly because that's what the car came with and also because I think it will handle more hammering since it has a better crank and forged pistons in it now, . I have a 4 speed and I know that can be hard on stuff. I used to have a 360 in one of my cars with a 4 speed and never had any problems with it either.

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