want to build new motor

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340demon

340demon

old man
Joined
Apr 9, 2006
Messages
240
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45
Location
Ocean Shores, Wa
I have a number matching 71 340 demon that I ordered in 1970 raced it for a while missed a shift and we all know what happened took the eng. out of the car and put in a 318-3 block 9.5:1c/r with all 340 parts heads cam ect. for a daily driver. want to put a new motor in now, I am thinking the 340 block with a stoker kit so it will look right from the out side have all the org. parts heads have been done to meet 1971 NHRA stock spec. car has 1.75 headers that i want to keep will be using car as a street rod with some trips to the local drag strips would like some in put from mopar guys thank you :evil2:
 
A 340 stroked to what? 400+ cubes? The heads (Stock) will be restrictive.
A 340 stroked with a 360 stroke crank? 367 or 372 @ .030 overbored.
 
The Edel.'s are a nice option. Think price and head bolts as well. You'll want to run and extra point of compression vs. iron heads.
Example would be 11-1 acts like a 10-1 iron head and would use 93 octane.

You could sell the OE head for a cost offset? I don't know if you want to keep the heads or not. Just an idea. Sell in conjunction with the OE intake and carb?
 
Ocean Shores? not many or any tracks near you. Did you hear they ran a race in Shelton a month or so back. Ever race your Demon at any of the old tracks like Arlington, Puyallup or Deer Park? It's a shame tracks aren't everywere like they used to be.
Rumblefish360's advise is pretty solid on the head thing. The stock heads can only do so much. My X's are running low 11's with a stock stroke 340 but I know they are holding me back.
 
Iwent to the shelton race and yes we run at all the tracks you mentioned plus mission SIR car won winter nat"l 1973 car went 12.53 there
 
do not think i want to sell parts yet look like the cost of a short block 340 or stroker kit would be with in $300 if i do the 340 like it should be done the heads are a different story will use all new bolts eather way i am running 101 leaded fuel now [110 leaded 92 unleaded 50/50 mix]
 
My X's are running low 11's with a stock stroke 340 but I know they are holding me back.
Click to expand...
Thats about the limit for stock heads in a full body car. Of course theres weight, but thats not the discussion right now. Power out put of the iron head is.
You could get into the 10's with an iron head. It's just starts becoming a deadicated race car at that point and weight reductions and all the nice things for the street start to go away. 10 is screeeeeaming fast for stock iron heads in a full bodied car. You would have to cam heavy duty and other things that probably are not going to be pump gas/street freindly.
 
Some good suggestions there Rumblefish. I believe it to be much more difficult to build a street Hot Rod verses a race only application. So MANY things you have to build around, trying to keep it pump gas friendly and tractable enough for daily driver. The stroker route is a good one. Even with steel production head castings, the torque these engines produce is amazing. With good deep port work with (max cross-section), these heads can flow good numbers 260-270 feet (cfm). A 408 stroker so equiped can lay down 500 ft.lbs. and 500 horsepower. Makes a sweet cruiser...when you stomp on the 'loud pedal'. Build it, good luck. And...as always...keep us posted. Terry.
 
If you start with a 360 block you will likely save almost enough money for a set of heads to feed a 400+ cube engine.
 
Whats the goal for the car ET wise ? Theres no reason the stock heads cant work with some good porting. The heads may limit peak power but with the big crank and smallish head the motor will make tons of torque and have a nice loq peak on the street. May J heads were enough to make almost 500hp with a stock stroke 340 and pushed 3600lbs in to the mid 11s.

I also dont feel the the Edelbrock heads are worth upgrading to. They still have a small port and while they may flow better then a ported J head, if your going to upgrade go big like a W2 or Indy.
 
thank for the comments the goal at this time to have a old car that was a very good stock elm car in the 70's,show well make a lot of sound out back do good burn outs in front of the cop shop, look stock and go almost as quick as i say it did way back when as you know the older we get the faster we were [sure nice to find old time slips in the tool box]
 
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