You’re 20* short on the camshaft duration. I ran a [email protected] solid in a 365 with 4.30 5400 max power. Now a 244/[email protected] with 3.91 max power 5800 revs to 6200 slower ET. Your valve “dwell” is too rapid. I was going to order a 268/278 for a 414 and was advised to spec 272/282 for 6700 rpm. Look up Huges Dyno charts. He’s running high 260’s at .050 in 360’s with oem castings #587. Your motor is trying to breath through a restricted dwell window. You need about 4-6* more advance too.
410 LA small block will not rev past 6000
- Thread starter FastMatt
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furrystump
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Nice car, drive the snot out of it. You should be forced to run higher rpm’s, not wanting to. The more RPM, the more maintenance. If there is some reason you need the rpm, small cubes, small stroke. Well, you get to ride the lightning! You have a little tire that doesn’t lend it self to hard launches? Step on up!
On the dyno chart peak power is about 20 mph less then where power takes a down turn, that's a lot more than 500 rpms. When I calculated rpm from peak hp and the torque at that speed it put peak hp just under 5,000 rpms.
It says peak 416 hp is at 93.75 mph and from what I can tell tq is about 440 lbs-ft @ 93.75 mph.
416 hp x 5252 / 440 tq = 4966 rpms. 360 hp x 5252 / 475 tq = 3980 rpm, 400 hp x 5252 / 360 tq = 5836 rpm.
So 416 hp @ 4966 rpms, 475 tq @ 3980 rpm and power falls off at 5836 rpm. If I'm reading the # right.
416 hp x 5252 / 440 tq = 4966 rpms. 360 hp x 5252 / 475 tq = 3980 rpm, 400 hp x 5252 / 360 tq = 5836 rpm.
So 416 hp @ 4966 rpms, 475 tq @ 3980 rpm and power falls off at 5836 rpm. If I'm reading the # right.
69b7bbgts
Well-Known Member
Two things I would do is set the lash at zero like one of the other folks other suggested and I know you're not going to want to hear it but try a carburetor
69b7bbgts
Well-Known Member
And more timing bring it at least up to 35
69b7bbgts
Well-Known Member
I think you have the components to go to seven grand, I would go with a solid lifter or to save some money right now. Put the lash at zero and bump the timing up. Those are two no-cost items that you can try right now
Not much other then them being very impressed that it made as much power at the wheels as it did. He said most "old school" cars that come in here with stroker small blocks rarely make much over 300 hp at the wheels. Nobody gets more mad than guys with old muscle cars when they dyno 100's less HP than they think they should. When I got there he asked me what I thought it was going to make I said "anything with a 4 as the first number", I could tell he almost rolled his eyes. But after the pulls he was impressed. I should have tried advancing the timing but with closed chamber heads, 12.3-1 and pump gas I figured I could not go any higher anyway. It may be worth a try.
Definitely performs well under 6000 rpm, just surprised if he (dyno operator) was encountering valve float at 116 mph / 6000 rpms he wouldn't mention it.
Ant
Well-Known Member
69b7bbgts
Well-Known Member
Cam specs?
Hughes 242/246 @0.050 cam with 0.587/0.592 lift with Hughes 1.6 shaft rockers. Hydraulic roller.
69b7bbgts
Well-Known Member
What is the lobe separation angle?
Dan the man
Well-Known Member
I don't know this as a fact, but from talking to guys who have a hydraulic roller cams none seem to pull over 5,800 rpm's. A couple have said that 6,200 rpm is pretty much the limit. Is this true, I don't know.
M_Body_Coupe
Active Member
ugh?
So I went from the Hughes 3844AL (hydraulic flat tappet) cam to a CompCams custom grind based on their XR292HR grind. Mine is using 112 LSA with +4 advance baked-in (290/300 advertised, 240/248 @0.050", .584/.580 lift on 108 CL).
CompCaps retrofit hydraulic roller lifters, running pretty tight (as in 1/2 turn on 20 TPI rocker arm adjuster, so that gives about 0.025" preload). Mind you this is a stroker W2 build, but that motor just pulls and pulls, in fact I got a nasty surprise the first time I had it out b/c it wound up so fast I pulled past 6500 RPM before I realized I was already there and the big tach light went off!!! (no rev limiter since this is just a street build)
Sooo...nope, haven't seen that lack of RPM to be the case with my hydraulic roller build, but perhaps the beehive springs along with geometery correction kit make that possible?
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Dan the man
Well-Known Member
What does the geometery kit consist of?
M_Body_Coupe
Active Member
Take a look here => B3 Racing Engines LLC - Mopar Rocker Arm Geometry Tech
In short, you measure some stuff out, you send in your info back to Mike who then custom machines the spacers that'll go between your rocker arm shaft and the head (either factory style saddle pedestals, or any of the aftermarket flat types that you'd typically find on stuff like W2s, etc.).
The goal of that kit is to re-align/correct the placement of the rocker arm vs valve tip due to any geometry issues that may be present in your current build. I've attached the original article by Jim Miler that details the theory behind this.
Keep in mind that Mike's kit is very specific to what you are running right now, as in: you go to a bigger/different lift cam, now the mid-point of your rocker's tip/roller is geometrically positioned elsewhere, and that may no longer be a best-fit.
Finally, last but not least: this kit may in fact cause you to lose valve lift, which was precisely the case for me (approx 0.010-15" at max lift). Coincidentally the old style MP W2 rocker arms showed the best lift, whereas my W2 1.6 ratio Harland Sharp did not.
Again, all this is heavily theory based. For a guy like myself who really only ever looked at the rocker roller to tip mark pattern, this is a lot more fuzzy and based on faith that the suggested geometry configuration does in fact result in a more stable valvetrain. Short of running the very same setup with and w/o the kit, and measuring the valvetrain harmonics each time you wouldn't be able to quanititavely compare.
EDIT
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I did a boat-load of blueprinting on this build (hey, numbers "turn my crank" lol). Here are a couple of pics (hopefully they attached OK), which show the results of getting the kit installed and the resulting tip alignment at seat and max-lifts for both the INTAKE and EXHAUST valves. I ultimately ran lash-caps because these regained some of the lost lift.
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