340 camshaft

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Look up the Mopar Performance Purple Shaft 450/455
Its a hot little cam designed for a mild 340.
 
Don't ignore Crower...good stuff and you get a FABO discount.

I wouldn't buy a Mopar cam...obsolete grinds ground by the lowest bidder...
 
Jason Holt said:
I was looking at the comp cams xe284h camshaft.
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Mattax said:
Running a few simulations of the the 220/226 Voodoo it produced more street torque than 3 CC cams with avg similar lift.
Comp cams classic 280480/480
Comp's 'replacement' 268/276; 264/264 (20-309-4, was called Magnum Muscle)
Comp's XE268. 477/480 This was the closest, making more power than the Voodoo starting around 3000 rpm, give or take some.

In terms of top end horsepower, all three above are in the same ballpark, and...
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I ran the CC 280 'High Energy' for around 80,000 miles on a 340, 727 with 3.23:1 rear and typical street tires (215/70-14 etc.) in my 67 notchb.
On top was a Street Dominator with 3310-3. Usually 340 exhaust manifolds exited the gasses, but For a few years it had headers.
The Turbo Action convertor (3000 rpm brake stall) was essential to making this streetable.
Pretty early on I installed Rhoads lifters. That helped a bit more with street driving. Still never fun when stuck idling in traffic .

This experience (and some others) is why I liked the Voodoo for what you first said you wanted. It will still spin into the high rpms but will be more streetable than the others discussed (possible exception being the cam Johnny Dart suggested).
If you want higher mph in the 1/4 mile, then the XE268 or 'magnum muscle' are the next best within the Comp Cams line, at least on paper/sim.

The suggestion to narrow the drivetrain desires is probably the next step. If streetable means driving 1000 miles on interstates, then gearing/tire combos that put the engine above 3000 rpm for hours at a time drive some people crazy. If it means driving in parades/car shows, then a high geared combo doesn't usually bother anyone. etc etc. Only you know what you may enjoy or consider acceptable.
 
My car is not too far from your setup, but probably heavier. I thought the Comp XE275HL looked like a pretty good fit and picked up the cam/lifter kit. I was going to run it with a 1.6 rocker which would put the lift around .560". Not sure I am going to use it now because a few things in my setup will be changing and I'm thinking of going to a solid.

Cam Style: Hydraulic flat tappet
Basic Operating RPM Range: 2,000-5,800
Intake Duration at 050 inch Lift: 231
Exhaust Duration at 050 inch Lift: 237
Duration at 050 inch Lift: 231 int./237 exh.
Advertised Intake Duration: 275
Advertised Exhaust Duration: 287
Advertised Duration: 275 int./287 exh.
Intake Valve Lift with Factory Rocker Arm Ratio: 0.525 in.
Exhaust Valve Lift with Factory Rocker Arm Ratio: 0.525 in.
Valve Lift with Factory Rocker Arm Ratio: 0.525 int./0.525 exh.
Lobe Separation (degrees): 110
 
Wow lots of information to sort out. My motor builder is trying to sway me into getting a roller camshaft but it sure is a price difference especially after buying roller rockets also.
 
Jason Holt said:
Wow lots of information to sort out
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Which is why it makes sense to cc your heads, measure the cc in the hole or height above deck of your pistons, and think about the gearing you will want for the driving you'll be doing. Finally, take a good look at what your heads will do. Hard to find a shop with a bench but this thread will ballpark the situation.
Small Block Head Flow Chart
That will narrow it down considerably.

The unported large valve factory head numbers that have been posted all look something like this.
upload_2019-12-13_9-19-7.png

This shows that opening the intake valve .3" allows 157 cfm to flow through on the bench.
Opening it .4 inches allows 193 cfm to flow through. Wow - big gain.
Opening it .5 inches only gains 7 cfm more.
And over .5 gains nothing.

So for this head, there is little point in looking at cams that open the valve more than .5 inches. Somewhere between .4 and .5 there's diminishing returns for increased opening.

Yes head flow can be improved. But its important to do so without losing velocity. If the air flow at low throttle openings slows down, fuel can drop out and the quality of the fuel air mix in the chamber will suffer.

Figure out what you have.
Then see what will work nicely for what you want to do.
Only if nothing reasonable can be found does it make sense to spend time and money on more modifications.
 
I run 11.80 at 116 with a solid flat tappet. A roller is not a trivial choice and really is for a serious effort motor. It necessitates more attention and money in valve train to get the performance potential out of the roller. Also the retro lifters can create oiling issues that can only reliably be addressed by bushing the lifter bores or tubing the galley. If you are pursuing that last hp. Ok. I don’t believe that is your goal. No hydraulics for me. The benefit of a hydraulic lifter is no maintenance. For the miles you are going to travel you would probably only need to check a solid once a year and that is a good chance to see how happy the motor is and catch any issues early. OOPS I always forget you may not have adjustable rockers. Sorry, still if it were me I would add adjustable rockers to the build.
 
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Oldmanmopar said:
Go solids. Lately the Hydraulics are not staying pumped up. We are on are third set from comp. They said they are having a problem. We tried different preloads with no luck. If the car sits for a little it clatters bad when starting it. Three motors same thing . I grabbed a set of lifters out of a old purple shaft kit problem solved.

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Ah - HA! Was wondering why my motor was clattering on start so much! Goes away quickly, but somewhat bothersome. Using a Comp cams XE275 HL - kinda rowdy for the street, but I like it! RT
Oldmanmopar said:
Go solids. Lately the Hydraulics are not staying pumped up. We are on are third set from comp. They said they are having a problem. We tried different preloads with no luck. If the car sits for a little it clatters bad when starting it. Three motors same thing . I grabbed a set of lifters out of a old purple shaft kit problem solved.

View attachment 1715435712

View attachment 1715435713
Click to expand...
 
cheech14 said:
Ah - HA! Was wondering why my motor was clattering on start so much! Goes away quickly, but somewhat bothersome. Using a Comp cams XE275 HL - kinda rowdy for the street, but I like it! RT
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Mattax said:
Great suggestion, and wise advice (learned the hard way - like most of us...)
Two additional suggestions
CC the heads while its apart. There's no reason to guess what the compression will be. I will never have an engine together again without knowing the actual head CC and piston above or below deck.
Stock heads aren't going to flow significantly more with the valves over .5" open.

I've used the street dominator intake and found it pretty decent single plane at lower rpms. It had a better rep than the Torker but I've not run them back to back. If you want to stay with single plane, I would try both. The Eddy RPM with a Holley 4150/60 will bring the air cleaner close to the hood. Check and double check clearance of stud and lid with clay or aluminum foil. A mild drop base will likely be needed.
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With an Eddy Air Gap and a 3 inch air cleaner I have just enough clearance to be comfortable closing the hood! This is on a 65 Barracuda. I am in the process of doing an article on manifold heights, but am still doin research. But - I will share this; The Air Gap is only about .240" taller than an LD4B, but is .640 taller than a performer 318/360 (all Eddies) Sure do like the way the engine gets RPMs with that Air Gap tho! (not the only mod to the motor by any stretch!)
 
cheech14 said:
With an Eddy Air Gap and a 3 inch air cleaner I have just enough clearance to be comfortable closing the hood! This is on a 65 Barracuda. I am in the process of doing an article on manifold heights, but am still doin research. But - I will share this; The Air Gap is only about .240" taller than an LD4B, but is .640 taller than a performer 318/360 (all Eddies) Sure do like the way the engine gets RPMs with that Air Gap tho! (not the only mod to the motor by any stretch!)
Click to expand...
Almost forgot to mention that the Air Gap required no matching to J or X heads - the LD4B and performer have much smaller runners (and one of them - I forget which - did not even have enough meat on the manifold to match to the larger ports - maybe both). Not sure on the LD4B for the 340 or the Performer Plus yet. Guess I better get off my butt and do more research!
RT
 
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