x head 340 best possible combo?

[deek1965]

Hey guy,s thanks for the info early on. The engine came from a 71 charger,is believed to be a magnum. it has both mounts from the 71 still intact,and rebuilt some time ago. the last nunbers on passenger side are 69, and 340-8 on drivers side. this is believed to have 10,30,1 compression, and i will be installing a278 duration 490lift cam. this car does not have power brakes or stering,so it should be ok to run a big cam,im guessing. tell me what HP this should have and what stall converter to choose. Is this a motor worth saving? Is it rare? What size carb should I get and is an edelbrock preferable over a holley? I have a factory holley off a mid-sixties newport with 440 TNT supposed to be an ex-highway patrol car. Would this carb be too big and does it have any value? #1416 list-4749-3

Thank you

[Christopher]

The Holley off of the 440 is rated at 585 cfm.Not enough for your 340.Don't throw it away though.It's a rare carb nowadays,and one of the 440 restores would buy it.

[340king]

Hi Deek,

We need some more info to help you out. The gear ratio has some affect on the convertor selection. Also, what are you using the car for: daily driver, street strip occasional driver, or full race?

You can run fairly large carbs on the 340's if you have the right combo of parts and a fairly light vehicle. In your case I would look for something in the 750 cfm range and consider a double pumper if you get a high stall convertor and have deep gears.

I would expect a mild 340 with this cam to make around 350-360 hp. depending on things like headers, carb and intake, etc.

[deek1965]

My charger will have 3:23 gears. Is it better to advance the cam 4 degrees? I have heard that the average chain will stetch 2 degrees upon break in. I am using a stock chain. I was thinking a 2200 stall would be about right. I will use the car for weekend cruising. I was told by an old chrysler mechanic that you should use a converter for a 340 and not my original 318 converter due to some kind of harmonics. He was a little vague. He said you could maybe get by with it but it wouldnt be right. I plan to drive this car hard and I want to build it one time and do it right any insight from experienced persons is highly appreceiated.

Deek

[Elwenil]

The 318 converter will work fine. The converter is the same for 273/318/340, with the exception of stall speed. As far as the balance, they are the same and will work fine as long as your 340 still has the stock balance. The 360 is the only one with the odd ball balance weight. It has a different stroke and needs different weight to offset it. The 273/318/340 all had the same stroke. As a side note, the new Magnum engines have a completely different weight also. An old 360 converter won't work with the new 360 Magnum.

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~Elwenil~ ~.\|/.~