I will have to make up my mind soon. I have the 340 in the Challenger now. It runs good and has about 350 HP. But I have a 1978 440 motor in my 70 GTX that I'm pulling out to put in a 70 440-4 bbl. I want to be close to stock appearing as possible. I will be using a Keisler 5-speed and need to make up my mind to use the 440-6pak or stay with the 340. I will be driving it a good bit so I thought that the 340 would be better on gas. But for wow factor the 440-6 would be better. The 440 has some mods done to it and it will be freshened up if I use it. I like the idea of a six pak motor,but I want to drive the car also. What do you guys think. 340 or 440.
Depends. What output is the 440? Correct me if I'm wrong but doesn't a 1978 440 have lower output. If it has around 390hp as the 6 barrel 440 had, it would be very tempting, if not keep the 340. A 340 is easy to modify and as Patrick has explain it can rival big blocks due to its light weight. The handling would be better with the 340. The insurance would probably be lower with the 340. The 340 is the more practical approach, the 440 is the more wow factor approach. It depends on what you value more between the two.
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The big thing now is stroker motors. You can buy a 408 stroker kit for the 340. The wow factor is tons of HP in a little bitty package and lite on weight. If you want I candy then the big motor (440) with a six pack is the why to go. I have been think about making a 340 stroker motor but install small block Hemi heads. It would be a 408 Hemi. You get the HP and the eye candy all at the same time. Try this links http://www.rodandcustommachines.com/smallblockhemiheads.html What do you think?
Being I've never rode in a 340, my answer is to go with the 440 6pack. In 74 and later they raised the compression the 440motors, which doesn't to me mean to much. It still has great potential, and with the right parts can easily be made into a beast. You will definiatly get alot more reaction with the 440-6. I get more people asking to see the motor, even though it's clearly marked asking does it actually have a 440-6 in it. Even when i had a 440 charger, this gets way more attention.
My suggestion is to keep the 340 in the Challenger and put the 440+6 in the GTX. The 78 440 is a motorhome motor, it is thin walled compared to the thicker walled 440's that were built 73 and before. The 340 will rev higher than the 440 will, even though the 440 puts out more torque off the line. Unless you rebuilt the 78 440, it has a cast crank and not a forged crank like the 70 440+6. For power purposes, forged is way better than cast.
< Message edited by mopar440 -- 4/17/2007 11:31:34 PM >
Thanks for the comments guys and I will weigh this matter some more. I just don't want to invest more new parts into the 340 if I decide to go with the 440. I also don't want to waste the 6-pak carb set up. I have a friend who will sell me a 70 440 for the GTX. I am putting the GTX back as close to original as possible. The Challenger will be doing street duty. The GTX, the show scene. I have to pull the 340 to put a rear main in, I plan to put new headers and exhaust. That is if I stay with the 340. This would also be a good time to drop the 440 in and add new headers. So that is where I'm at.
AmericanMuscleCarRev thanks for the reply. I have decided for now to freshen up the 340 and add a new cam kit and new headers. Also new radiator and intake and carb. A milodon 7quart pan and a mild port and polish on the stock heads. The car is stripped at the body shop and the engine and trans have been pulled. My brother works at an auto machine shop and he will do all the machine work. The engine only had 21,000 miles on it since a total rebuild in 86. I have the 1" rear sway bar and 1 1/4" for the front. The rear gears are 3:91 and a Kiesler 5-speed will be going in. I'm hoping for over 300 HP at the wheels and I don't see any problem with that goal. The brakes have been upgraded front and back. The car will be a cruiser and driven alot weather permitting But this does leave me with a spare 440 and I don't think thats a bad thing. I'll more than likely just clean it up and put it on an engine stand just for looks.
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340 or 440-6 - 
The brakes have been upgraded front and back. The car will be a cruiser and driven alot weather permitting 
But this does leave me with a spare 440 and I don't think thats a bad thing. I'll more than likely just clean it up and put it on an engine stand just for looks.
