12's from a 340 naturally aspirated.

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VonCramp

VonCramp

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Looking for members who have obtained 12's from their stock stroke naturally aspirated 340's. I have a standard bore '72 340 that got me in the 13's at 104 mph with a flat cam. I have since upgraded to a solid roller .600 lift Comp Cams and cometic head gaskets. The pro comp heads chamber didn't like the .027 piston out of the deck hitting them. Lesson learned. I am running 3:91 gears on a 29" tire with a 18-spline a body 4-speed. Can it be done? I sure hope so.
 
nothin' to it. Your 104 mph is enough to get into 12's. Not a tall task at all....
 
if you are running 104 mph .....you should be in 12s.....
 
Good to know! My non-Mopar buddies seem to think only small cubed Fords can do it. I am hoping to see members' combinations so I can take notes.
 
318willrun said:
then throw in a Automatic with a good converter...... :)
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I would but it is a factory 4-speed big block 'Cuda. I already bastardized it with the 340. I don't want to cut any holes in the floor. I will work on my driving skills.
 
My 340 ran 11.60 @ 116 in my 3240# Dart. It had ported Edelbrocks, 11.4-1 compression and a Hughes hydraulic cam and ran on pump 93.
 
justinp61 said:
My 340 ran 11.60 @ 116 in my 3240# Dart. It had ported Edelbrocks, 11.4-1 compression and a Hughes hydraulic cam and ran on pump 93.
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Wow!!! Congrats on that. I have the standard flat-top pistons. Although they do come out of the deck .027.
 
Ignition timing isn't your problem. Your 60 foot times are the issue if you are running 104mph. I'll guess in the 2.10-2.20 range.
 
My god, get the car to hook and NOT throw more power at it. LOL

2.49 is good for an 18 flat car. Low 12's engine in a 20 second chassis. Work on the chassis, that's your problem area.

You'll have to figure out the timing on your new cam same as you should have for the old cam. Initial first, then total.
 
crackedback said:
My god, get the car to hook and NOT throw more power at it. LOL

2.49 is good for an 18 flat car. Low 12's engine in a 20 second chassis. Work on the chassis, that's your problem area.

You'll have to figure out the timing on your new cam same as you should have for the old cam. Initial first, then total.
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I will do that. I am running M&H cheaters. They seem to do all right. I kinda' got off track and made this about my driving. I am hoping to see more 12 second street 340 combo's, though.
 
I can think of only one naturally aspirated 340 4 speed car on this forum that doesn't do 12 seconds - yellow rose! LOL :poke:
VonCramp said:
I will do that. I am running M&H cheaters. They seem to do all right. I kinda' got off track and made this about my driving. I am hoping to see more 12 second street 340 combo's, though.
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VonCramp said:
Good to know! My non-Mopar buddies seem to think only small cubed Fords can do it. I am hoping to see members' combinations so I can take notes.
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I like Fords, but your non Mopar buddies are stupid.
 
VonCramp said:
Looking for members who have obtained 12's from their stock stroke naturally aspirated 340's. I have a standard bore '72 340 that got me in the 13's at 104 mph with a flat cam. I have since upgraded to a solid roller .600 lift Comp Cams and cometic head gaskets. The pro comp heads chamber didn't like the .027 piston out of the deck hitting them. Lesson learned. I am running 3:91 gears on a 29" tire with a 18-spline a body 4-speed. Can it be done? I sure hope so.
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104 mph should put you around 12.70's, and a 2.49 60ft should be around 17.90's. You must have a super heavy car with high gears or spinning real bad.
 
I did 12.72 @ 108 MPH with a 273 in a Valiant 4 speed with a 600 CFM Holley, but that was with 4.56 ratio rear end. You can do it, too. edit: 6400 RPM at the end of track.
 
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29" tire with 3.91's, try a shorter tire. What is your rpm at the finish line?
 
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