340-6pak Dyno Results
- Thread starter 2fine69s
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moper
Well-Known Member
Sounds like they drilled the main well air bleeds slightly. That's the one on the top of the passage the jets screw into. That would help lean out a rich condition at part throttle and cruise.
D-mailman
Well-Known Member
+ .030 (4.070) and 3.580 = 372.60 CID. Good job on your build.....good numbers too. You will like it just ...fine69S. Terry.
2fine69s
69 340-6pak Rag Top
Mike,
You are correct. I came up with 372.6. Haven stated it as aprox. 377, I was thinking of a .060 bore,I missed the boat. That makes me even happier, less inches and the same Horse power/Torque. Thanks for your help.
Martin
You are correct. I came up with 372.6. Haven stated it as aprox. 377, I was thinking of a .060 bore,I missed the boat. That makes me even happier, less inches and the same Horse power/Torque. Thanks for your help.
Martin
Idaho
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Could you comment on how you arrived at your decision on compression? It seems to me even with the aluminum heads you must be close to the upper limit for running pump gas. I suppose not getting too wild with your cam helps.
I'm interested as I have a '73 340 rebuild planned. I'd like to build it to be similar to an early 340 or maybe a little better. With the factory compression at 10.5 this is a major consideration in my planning. In particular, I have to decide whether to invest in aluminum heads.
Thanks
Arlie
I'm interested as I have a '73 340 rebuild planned. I'd like to build it to be similar to an early 340 or maybe a little better. With the factory compression at 10.5 this is a major consideration in my planning. In particular, I have to decide whether to invest in aluminum heads.
Thanks
Arlie
moper
Well-Known Member
Idaho I would suggest another thread on that subject. It gets fairly involved, and you should start thinking about it before any parts are chosen.
Hey Martin, any news on your head flow numbers and your cam specs yet? I'm particularly interested as I have a combo almost identical, .030" over 360, 10.8 compression, custom Bullet hyd / roller cam, ported Eddy heads, 1-3/4" headers, and a much modified LD340 intake and large TQ carb.
'Enquiring minds still want to know these things'
'Enquiring minds still want to know these things'
2fine69s
69 340-6pak Rag Top
Raymond,
The engine specs are more mild than you would expect. The heads were only blended and match ported. They flowed: 244 @ 500. The cam is: 224-228 duration @.050. The lift is .540 and .513. Your 360 should make a ton of torque. I built one with a solid roller .575 and .308 advertised duration, and it would blow the tires off at 40 mph.
Martin
The engine specs are more mild than you would expect. The heads were only blended and match ported. They flowed: 244 @ 500. The cam is: 224-228 duration @.050. The lift is .540 and .513. Your 360 should make a ton of torque. I built one with a solid roller .575 and .308 advertised duration, and it would blow the tires off at 40 mph.
Martin
Martin, you're right about the torque, I'm having a lot of traction problems, my cam is pretty mild 222 / 234 @.050" with .510" / .509 lift but I am using 1.6 rockers so that has given it a little more. I played around with my heads a little myself and had them flowing about 265 but I have since got one of the local head gurus to do a little more. He has them flowing in the low 280's, not a lot more at max lift but the low and mid lift figures are awesome compared to how they were. He said there's more in them yet, but there is more than enough air there for my combo as it is, and to get more out of them it would start to slow port velocity.
What sort of lobe seperation is your cam? Mine is 112*. I was basically looking for a reasonable idle and told them I needed around 15 inches of manifold vacuam, it's right on the dot at 15"
I have a few hundred miles on it now and I will get it on a friends chassis dyno in the near future to get the carb jetting right and maybe try some different timing settings.
What sort of lobe seperation is your cam? Mine is 112*. I was basically looking for a reasonable idle and told them I needed around 15 inches of manifold vacuam, it's right on the dot at 15"
I have a few hundred miles on it now and I will get it on a friends chassis dyno in the near future to get the carb jetting right and maybe try some different timing settings.
2fine69s
69 340-6pak Rag Top
Raymond,
My lobe seperation is 110*. Let me know what the chassis dyno says. I'm going to do the same.
Martin
My lobe seperation is 110*. Let me know what the chassis dyno says. I'm going to do the same.
Martin
Yuuuuuummmm. Sounds like fun.raymond said:
Modded LD-340? Like this? With plenum mods? Gasket matched?
Yeah it has all those mods plus the heat crossover has been welded up [it was on a set of iron heads originally] pretty useless on Eddies though and it has also had a bit of a port job as far as I could get into the runners and opened up to match those big port Felpro gaskets 1213?? , the ones with the blue sealing strip around the port openings.
I run it with a 1/2" 4 hole insulator spacer not enough room to get any more under it, but it is enough to make a bit of a difference it seems to idle a little better and come off idle a little more cleanly. Prolly keeps the butterflies up out of the turbulence in the plennum a bit. I will get some cold air into it at some stage in the future as well. Every little bit helps!!!!
I run it with a 1/2" 4 hole insulator spacer not enough room to get any more under it, but it is enough to make a bit of a difference it seems to idle a little better and come off idle a little more cleanly. Prolly keeps the butterflies up out of the turbulence in the plennum a bit. I will get some cold air into it at some stage in the future as well. Every little bit helps!!!!
mikesduster
Well-Known Member
2fine69s said:
martin,
whos cam are you useing??....540/.513 seems like alot of split lift to me??..but im NO expert!!
why in the world didnt you keep that BAD 360??? :wav:
2fine69s
69 340-6pak Rag Top
Mike,
I'm using a Bullet cam. They are in Olive Branch, MS. The guys at H&F Performance in Wilson, NC, highly recommended them. I let them pick the camshaft after telling them what I wanted to do with the car,since they build stock, super stock and modified IHRA engines. Well to tell you the truth, I'm a 69 kinda guy. They have always been my favorite. I bought a 71 Dart Swinger, nice car, thinking that I would be satisfied if I stuffed a screamer under the hood. It would go but,Well I wasn't satisfied with the look. I took it to the Mopar Nats and sold it. I have had a 69 hard top for over 20 years, and was looking another, so I found this 69 conv., and it was on again! This is the one on my garage page.
Later,
Martin
I'm using a Bullet cam. They are in Olive Branch, MS. The guys at H&F Performance in Wilson, NC, highly recommended them. I let them pick the camshaft after telling them what I wanted to do with the car,since they build stock, super stock and modified IHRA engines. Well to tell you the truth, I'm a 69 kinda guy. They have always been my favorite. I bought a 71 Dart Swinger, nice car, thinking that I would be satisfied if I stuffed a screamer under the hood. It would go but,Well I wasn't satisfied with the look. I took it to the Mopar Nats and sold it. I have had a 69 hard top for over 20 years, and was looking another, so I found this 69 conv., and it was on again! This is the one on my garage page.
Later,
Martin
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