68-70 Manifolds on 72 340?

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domdart

domdart

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I am selling my Harley so I am going to put some money into my 68 Dart. I am taking off the D453 headers and go with exhaust manifolds. My 72 340 was put back to 68 specs. It has 2.02 and 1.88 valves, a forged crank, a cam, and 10.5 to 1 pistons. Will the higher flow 68-70 manifolds bolt right up to the 72?
 
domdart said:
I am selling my Harley so I am going to put some money into my 68 Dart. I am taking off the D453 headers and go with exhaust manifolds. My 72 340 was put back to 68 specs. It has 2.02 and 1.88 valves, a forged crank, a cam, and 10.5 to 1 pistons. Will the higher flow 68-70 manifolds bolt right up to the 72?
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As long as you don't have W2 heads or something exotic all 340 heads will except your 68 to 70 exhaust manifolds.
 
Are you asking for physical fit or whether the engine will not lose anything going from the Doug’s to the 340 HiPo’s?

Sounds like you may still be in the headers category to not choke it down. What’s the specs on the cam?

There was a really cool article in Hotrod where Vic Edelbrock got an early 340 and started doing testing and development on the ‘new’ 340. They started out pretty basic and added a part and then did a dyno pull. It was the first time the LD340 had ever been in print.
Mopar Manipulatin’ , HRM August ‘69
 
The cam is comp cam CL20-224-4, duration 274/286, lift .488/.499. It has an air gap also. When I did the car I thought I wanted as much performance as possible. I rarely use any of the power. I made this decision driving home from Carlisle on the turnpike going 70 mph at 3500 rpms for an hour.
 
It has a 3.55 in it. I just ordered a sure-trac II for my 3.23. I want less rpms and less exhaust noise.
 
You will be fine. I run a set with more engine than you listed and it has W2 heads on it. I got tired of fussing with headers. Got manifolds and opened the ports so they where as close as I could get them. I can not tell a difference at all. Did I leave a few HP's behind? Sure but I can not tell on the street at all. Runs great and no more BS header problems. You'll be fine... so YES they will be bolt on to your heads with no problem at all.
 
domdart said:
It has a 3.55 in it. I just ordered a sure-trac II for my 3.23. I want less rpms and less exhaust noise.
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I understand where you are coming from. I got tired of the noise and drone as well. Do the exhaust first. I did and stayed with my 3.55 gear. Also If it is an automatic the correct converter stall helps a lot as too.
 
domdart said:
The cam is comp cam CL20-224-4, duration 274/286, lift .488/.499. It has an air gap also. When I did the car I thought I wanted as much performance as possible. I rarely use any of the power. I made this decision driving home from Carlisle on the turnpike going 70 mph at 3500 rpms for an hour.
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I had the same situation as you....driving 70mph at 3200 rpm's (if I remember correctly) with 3:23 gears. I bit the bullet and swapped out my 727 auto for a five speed manual. Now I can run 70mph at 1900 rpms.
 
My car is a four speed manual. Five speed sounds interesting, I'll have to look into that.
 
domdart said:
I am selling my Harley so I am going to put some money into my 68 Dart. I am taking off the D453 headers and go with exhaust manifolds. My 72 340 was put back to 68 specs. It has 2.02 and 1.88 valves, a forged crank, a cam, and 10.5 to 1 pistons. Will the higher flow 68-70 manifolds bolt right up to the 72?
Click to expand...
Yup. You will of course have to have new head pipes made.
 
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