Just for fun, your opinion on this cam in this combo.

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1968FormulaS340

1968FormulaS340

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The cam.
Voodoo Solid Roller Cam - Chrysler 273-360 273/279 - Lunati Power

The rest of it.
1968, 340, balanced with forged stock replacement pistons.
X heads with some moderate cleanup and port work.
Factory cast iron intake and HP exhaust manifolds, both unmodified
Factory 625 AVS, unmodified
4 speed
3.91 gears
2.5" TTI exhaust, off the manifolds to DynoMax UltraFlow mufflers.

Opinions?
 
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That's a lot of cam for a stock 340. Real compression is closer to 9.5 to 1. I had a buddy that had a 70 dart 340 4 speed and 3.91 gears. To my surprise it went quicker with a 508 cam.
 
1968FormulaS340 said:
The cam.
Voodoo Solid Roller Cam - Chrysler 273-360 273/279 - Lunati Power

The rest of it.
1968, 340, balanced with forged stock replacement pistons
X heads with some moderate cleanup and port work.
Factory cast iron intake and HP exhaust manifolds, both unmodified
Factory 625 AVS, unmodified
4 speed
3.91 gears

Opinions?
Click to expand...

My opinion........it's a poor choice, given stock unmodified, intake and exhaust manifolds.....don't be surprised if you get passed by a well sorted 318..................
 
aaronk785 said:
That's a lot of cam for a stock 340. Real compression is closer to 9.5 to 1. I had a buddy that had a 70 dart 340 4 speed and 3.91 gears. To my surprise it went quicker with a 508 cam.
Click to expand...

Ok, let's put the compression at a corrected and verified 10.7 to 1.
 
284/484 purple cam comes to mind. But still headers would be better! i will be running an old oval track grind the 288/ 497 with 108 lobe separation. Hope it runs sweet!!:steering:
 
JBurch said:
My opinion........it's a poor choice, given stock unmodified, intake and exhaust manifolds.....don't be surprised if you get passed by a well sorted 318..................
Click to expand...

Damn..that would be embarrassing:eek::eek:
 
If I were going to spend money on a roller I would go with a custom grind. That's what the F.A.S.T guys do. Sound like that's kinda what you want. I would also fined a avs of a 440 magnum. Looks stock but about 100 more cfms.
 
Let me do it Yellow Rose-style: get a custom cam.
Call one of the cam grinders mentioned in many other threads and tell them what you want/expect. Listen to their recommendation.
 
That's a big cam for what you got. You're putting a cam in with a lot of lift on heads that aren't ported and don't have the flow for it. Not to mention the intake/exhaust manifolds. You're gunna try and stuff a lot of air through parts that won't like it. And that carb is way to small for how much duration that cam is.

Mismatched combo.

My suggestions? RPM air gap. Headers. 750 double pumper. And call a custom cam grinder. The best part of solid rollers is how much more area under the curve you get. So you can get a lot more duration/lift/area under the curve, with what is essentially a smaller cam. But there's really no point in beyond a cam a couple steps up from stock with the rest of your combo (except your compression ratio). Also keep an eye on DCR.
 
I think that cam is pretty big, but I will stop short of saying it's too much. 10.7:1 is good. Ported heads is good. Early HP manifolds is good. 3.91 gear and a 4 speed is real good. While I think there probably are better choices, 1) it will be far from a dog and 2) it will sound shag nasty. I assume you DO plan on running the correct springs? I forget........what are the specs on the current solid roller in the engine? Just wondering how big a step up this cam is. That should give you some clue as to how it will perform.

Oh and the single biggest thing I see is you will need more carburetor. But I gotta say it........and I think I know the answer, but I gotta say it. Your combo would absolutely THRIVE with a quality set of headers. I know all the I knows.......but in your case, they would REALLY add to! Not like you cain't keep the original manifolds.

If you coupled more carburetor with say, an air gap and good headers, you could be talking about close to another 50 HP. Maybe more.

The car's probably far from a dog now. I just bet the cam you have now is somewhat comparable to the one you are looking at, so that's what I would base any guesses on as to the change........not a bunch of armchair wannabe dyno operators.
 
aaronk785 said:
If I were going to spend money on a roller I would go with a custom grind. That's what the F.A.S.T guys do. Sound like that's kinda what you want. I would also fined a avs of a 440 magnum. Looks stock but about 100 more cfms.
Click to expand...

Ya but the rest of his combination is basically stock..those f.a.s.t. guys are using ported intakes,ported ex.manifolds stroker cranks tweaked to the max carbs.far far far from stock..
 
Personally I dont think its too bad. If i were to suggest I probably would have went around mid 230s on a 112 ls with a single pattern only because of the exh manifolds.Other than that I think its ok plus you also have the ability to loosen/tighten lash a little.Dont forget this is a solid with short seat timing not a hyd with longer seat duration dont just look at the .050.
 
RustyRatRod said:
I think that cam is pretty big, but I will stop short of saying it's too much. 10.7:1 is good. Ported heads is good. Early HP manifolds is good. 3.91 gear and a 4 speed is real good. While I think there probably are better choices, 1) it will be far from a dog and 2) it will sound shag nasty. I assume you DO plan on running the correct springs? I forget........what are the specs on the current solid roller in the engine? Just wondering how big a step up this cam is. That should give you some clue as to how it will perform.

Oh and the single biggest thing I see is you will need more carburetor. But I gotta say it........and I think I know the answer, but I gotta say it. Your combo would absolutely THRIVE with a quality set of headers. I know all the I knows.......but in your case, they would REALLY add to! Not like you cain't keep the original manifolds.

If you coupled more carburetor with say, an air gap and good headers, you could be talking about close to another 50 HP. Maybe more.

The car's probably far from a dog now. I just bet the cam you have now is somewhat comparable to the one you are looking at, so that's what I would base any guesses on as to the change........not a bunch of armchair wannabe dyno operators.
Click to expand...

I have a Victor 340 and a Holley 800dp in the garage, couple those with these.
https://www.summitracing.com/parts/hok-5204-1hkr/overview/year/1968/make/plymouth/model/barracuda

Or a similar header, should be a big change.
 
the 1968 340 manual cam was 276*/284*, with stock manifolds and a 625 avs. Nhra superstock cars run bigger cams with the little stock carb-jetted up as needed. run it, it will scream with the right valvesprings and tune
 
I wouldn't even consider a roller for the kind of build you're talking about. I think youd be ALOT happier and so would your motor and wallet with the Mopar 284 cam, or the 509 at the most. Do yourself a favor and stay with a hydraulic or a mild solid
 
Dartish said:
I wouldn't even consider a roller for the kind of build you're talking about. I think youd be ALOT happier and so would your motor and wallet with the Mopar 284 cam, or the 509 at the most. Do yourself a favor and stay with a hydraulic or a mild solid
Click to expand...

The engine already had a solid roller when I got the car back in 2004. The old cam was a Crower (the cam has been discontinued so I can't give the exact specs but it had a little less lift, more duration and about a 400hpm higher operating range).

I have actually been running the combo from my original post for several years now and I must say, RustyRatRod, nailed it perfectly with his assessment in post #15.

Im reall happy with how it works and I know, with just a weekend of bolting my old speed parts back on, the car would shine.
 
If YOURE happy with it, that's all that really matters. Its YOUR CAR YOUR MOney. Everyone has their opinions of how you should build it and some are very logical. But in the end, all that really matters is that it runs and you're happy right?
 
..the flow in stock heads stall at about .480 lift
anything higher will diminish returns
 
Stoker340. I know those engines are from stock. But that doesn't mean the cam grinder couldn't spec a cam for his combo. That's what I was saying. Let the experienced grinder pick the cam. Someone like hughes or engle or racer brown etc.
 
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