E-Bodies.org Cuda Challenger Forum

I am new to mopars.  So I am probably asking a question most of you guys have known for years.  I have a stock 1971 340, j heads big valves.  It's a 4 speed, 355 gears with power disk breaks.  What would be some things to change on the engine to make it faster.  It is very streetable now and I drive it a lot so I don't want to mess that up.  Stock intake with a 600 holly carb.  Love to hear some ideas. 

              Welcome aboard @Bartman (https://forum.e-bodies.org/mlist/bartman_784)     :welcome:   The engine gurus will weigh in shortly.   :rebelflag"

Quote from: ec_co on August 02, 2017, 06:03:35 PM
also consider EFI over a carb setup. better driveability, better engine life, easier starts, plenty of flow and about the same power curves. companies like FiTech http://fitechefi.com/ or Edelbrock, FastEFI

                                   :iagree:  EFI rocks !    :rebelflag"

The 340 is an engine that loves high RPM's It is not a bottom end torque motor. So do all of the standard hop ups that you would do on any other brand of engine. One thing that a lot of guys forget is to upgrade the valve springs with any cam change that you do. How many miles on this engine ? it is a 40 + year old motor, so it might need more than a quick tune.  Find someone with a leak down tester or rent one to find the true condition of your motor.

I hadn't really thought about efi.   I believe it's better but I am not sure if I could
Figure out how to hook it up and get the bugs worked out. 

The engine was rebuild about 5 years ago. I broke the motor in and the engine might
Have 500 miles on it. 

Quote from: Bartman on August 02, 2017, 06:39:13 PM
I hadn't really thought about efi.   I believe it's better but I am not sure if I could
Figure out how to hook it up and get the bugs worked out.

check out that FiTech link, it is a plug and play system unlike most of the other EFI setups out there. very hobby friendly. better yet, check some youtube reviews and installs to see how easy it is.

https://www.youtube.com/results?search_query=fitech+efi+review

https://www.youtube.com/results?search_query=fitech+efi+install

Well then there is bottle fed or blown

:andyangel:

If you carb it 750 is a nice size for a 340. Headers are a great mod. The stock intake manifold is a good one and you'll gain more by changing the camshaft instead. I didn't see what compression ratio it might be?

I was told the pistons are what would have been used in a TA motor.  1970 pistons
So if that is true I guess it would be somewhere around 10

Think of the engine as an air pump so mpre air in & out is what it is all about ,
Sounds like you have the exhaust side figured out with TTi headers !
Better heads are a must , the X & J heads are not very good at all , W2 W5 are an awesome upgrade but not cheap , Airwolf should be a better choice bang for the $$ Edelbrock are just a sideways move basically a stock head but lighter in alum .
Intake to match is needed as well , there are specific intakes for W series heads & the RPM air gap is great as well as the old LD340 or even the stock intake is no slouch either .
The cam is the heart of the whole build it will control where it makes power in the RPM band & how well it works at any given rpm .
600cfm is far too small for 340 , I use 2x the CI so 700 would be ideal , 750 will work , the factory used a 800 cfm TQ carb
EFI is a decent option , the engine will run far better with efi especially with a larger cam but this is not cheap ,  I far prefer dry intakes with multiport injection right behind the intake valve over throttle body injection as you can have the same problems that a crab will by having fuel drop out of the air flow before reaching the cylinder causing cylnders to misfire .
I built a race engine with EFI , it had large port heads & intake with large headers & a .680 lift roller cam , I broke it in with a carb & it did not idle well at all even above 1000 rpm , but once I installed the multiport EFI every cylinder fired every time &it would  idle evem down to 700 rpm easily & had amazing response .
Let me know what help you need & welcome by the way !!

Thanks for the input.  i think I am going to do some research and see what some things cost.
I probably will have some more questions.  Thanks

quick math W2 or W5 will run you $4k ,
multiport EFI $4500

New R3 block with W8 or W9 heads will make 700 + hp though  :yes:

Before you purchase heads check TTI's web site because only certain heads fit with their headers and 340's.  You would hate to spend all of that money on headers and the heads don't fit or vise versa.  Good luck

 :welcome:    :needphotos:

I disagree with Chryo on the Eddy heads being about the same as the stock X or J. The flow numbers are better depending on who you ask. But they have a much better quench area and are aluminum so they tolerate more compression without detonation and run cooler. Price is very reasonable compared to most others. There is also the weight savings over cast iron. They are also a direct swap out for factory heads so stock configuration intake, exhaust and accessories bolt up. The W series heads are awesome race heads. Flow big numbers. The down side is they require W specific intake and headers and are very pricey. If your running on the street through full exhaust big flowing heads are choked down. So to me it makes no sense to run them. Unless your drag racing with open headers. 

340's are my favorite motors. Been building and running them for many years. Tried many different combinations with pretty drastic results. Cams definitely effect the way it runs. Some cams that should make big power have poor throttle response. I probably have tried at least 6 different cams in this motor. The one listed on top below was the best overall cam hands down. I have manual brakes so I can't say if it will effect power brakes or not.  It's a choppy sounding thing. So if your don't like bumpity bumpity bumpity I wouldn't recommend it. The second one is pretty good runner also. Doesn't effect power brakes. Has a pretty good lope.  But not as good performer overall. It's a choppy sounding thing. So if your don't like bumpity bumpity bumpity I wouldn't recommend it. 

I'm not saying this is the worlds best combination. But it runs extremely strong and sounds excellent with instant throttle response. This is my combination I'm currently running in my Cuda.
030 over 340 4 speed with 3.91 gears
11.1 compression
Edlebrock RPM heads
Edlebrock RPM Air Gap intake
Quick Fuel 750 mechanical secondary carb
TTI headers and Exhaust
Comp Cam

Myself & a friend went through 10 sets of Eddy heads at the speed shop he worked at & he bought the best pair , they were core shifted horribly & not fixable by porting either , they do have a slightly better chamber but as always you get what you pay for so yeah they are cheaper , a few more $$ will get you a lot more IMO  :alan2cents: I have not seen the HP gains with Eddy either but we did gain $! RwHP on a dyno using ported 308s over ported X heads if you want to cheaper !
  I did a W2 stroked 408 in a Lil Red Express , it was Nutz !!
I have had poor results using comp cams , oddly they are not the ONLY cam company in the world , I have used a Lot of Engle & Lunati with great results , Crower, Bullet, Mr 6 Pack are supposed to have great Mopar specific grinds also but I have not them

Quote from: Chryco Psycho on August 04, 2017, 11:13:34 AM
Myself & a friend went through 10 sets of Eddy heads at the speed shop he worked at & he bought the best pair , they were core shifted horribly & not fixable by porting either , they do have a slightly better chamber but as always you get what you pay for so yeah they are cheaper , a few more $$ will get you a lot more IMO  :alan2cents: I have not seen the HP gains with Eddy either but we did gain $! RwHP on a dyno using ported 308s over ported X heads if you want to cheaper !
  I did a W2 stroked 408 in a Lil Red Express , it was Nutz !!
I have had poor results using comp cams , oddly they are not the ONLY cam company in the world , I have used a Lot of Engle & Lunati with great results , Crower, Bullet, Mr 6 Pack are supposed to have great Mopar specific grinds also but I have not them

I'm a fan of the Lunati cams as well. But this Comp I'm running now just seems to hit a sweet spot in the 340. I would be more for the W2's if it wasn't for the different intake and exhaust configuration. Indy looks to have some newer small block heads that show some good numbers. But they to are pricey and have the intake and exhaust configuration issue. 

My 416 stroker has the made in China Procomp aluminum heads with custom machine work by my engine builder. I saved some money by not getting the Edelbrock RPM heads that will also require machining. Engine makes 491 HP and 528 FT-LB.

Quote from: 7212Mopar on August 04, 2017, 01:02:06 PM
My 416 stroker has the made in China Procomp aluminum heads with custom machine work by my engine builder. I saved some money by not getting the Edelbrock RPM heads that will also require machining. Engine makes 491 HP and 528 FT-LB.

Man. Those are some great numbers. I have a stroker motor build on the horizon but just waiting on another block. I don't want to disassemble the motor in the car because it's pretty nice and I don't want to use my numbers matching motor because I feel it needs to be put back stock. Plus I don't want to take a chance throwing a rod or something through the side of the block.

Grab a 350 roller block , they pretty much give them away !!

one thing to really consider what this basic upgrades would cost vs going into a gen3 hellcat shortblock and mating it to your current transmission

Sky's the limit, we went from simple bolt-on's to $20k budget....