410 LA small block will not rev past 6000

[PRH]

Based on the OP’s description………and assuming he understands how what he said will be interpreted……I’m comfortable with my assessment of what’s going on.

Unfortunately, it’s an expensive proposition to test it.

I’d say, he’s lived with it this long……..just keep driving it, and possibly look into addressing it when the engine gets freshened.

 

[Ceedawg]

20+ years ago we chased our tales looking for more rpm out of my friends Stocker.
Adding spring pressure did nothing…….. in fact it seemed like when things went in the crapper, it happened more abruptly.

We were trying different cams from different suppliers, different ramp rates, etc……. Without success.
It was good till about 6k, but we really needed another 500rpm to get the car thru the finish line clean.

At that point, I was pretty sure the lobe designs and springs weren’t the issue.
So, we tested Hyd lifters vs solid lifters on the dyno.
Poof……with the solids, the engine would run to 7k no problem.

Why they’re beating around the bush on these idiot ideas I’ll never know, LIFTERS LIFTERS LIFTERS. Quit wasting y’all’s time with head flow and springs

 

[PRH]

Here’s a screen shot from a test on a 427bbc that was having some HR lifter issues after 6400rpm.
Courtesy- Nicks Garage:

It’s good……..right up until it’s not.
Actually, getting 6400 out of a HR in one of those is pretty good.

 

[MOPAROFFICIAL]

He said above he had 2.055 valves installed and then did some work on the ports. If it was good work the heads will easily work to 7000

I was reading all that too and saying nah.. 2.05 eddy's ported, not destroyed, should be plenty enough for 7k @410cid.
I've had 410 cid sb with balls deep ported j heads get into 7200 rpm no problem...Though the solid roller helped too .lol

 

[Remow2112]

I would change the all in timing to 36 degrees. See if she will rev then.

 

[-Boosted-]

Get it figured out yet?

 

[AJ/FormS]

Well if you look at 112 mph the dyno graph is showing about 400 hp and 360 tq if I'm reading it right.

400 hp x 5252 / 360 tq = 5836 rpms and a couple of mph above that it drops off. So 6000 rpms does seem to be the end of the road.


I now get why 5252 don't happen at 88 mph, cause the torque and hp are scaled different so even though they cross at 88 mph there not the same hp/tq amounts there.

Yeah, those graphs can be tricky, lol.

 

[FastMatt]

Thank you for all the idea's! I'm going to play with them one by one, and see if something fixes it. I for sure have came to the conclusion I need a bigger and solid roller cam if I want to play in the 6500+ RPM range anyway. The car is such a hoot to drive now not sure I want to do that in fear of loosing low end and possibly the EFI not playing well with the cam. I never meant for it to be a drag car just a fun stick shift street muscle car, and that it is.

 

[340sFastback]

Thank you for all the idea's! I'm going to play with them one by one, and see if something fixes it. I for sure have came to the conclusion I need a bigger and solid roller cam if I want to play in the 6500+ RPM range anyway. The car is such a hoot to drive now not sure I want to do that in fear of loosing low end and possibly the EFI not playing well with the cam. I never meant for it to be a drag car just a fun stick shift street muscle car, and that it is.

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Awesome car. I would wait till engine needs work and go solid roller then.

 

[trapster]

Did you by chance check the fuel pressure ? the ez efi says it is good to 650 hp and it looks like you may be getting close to this. but if the fuel filter is clogged or the fuel lines too small then it may not be able to go over 500 ?

 

[273]

Yeah, those graphs can be tricky, lol.

Use to assuming that 5252 rpm is at crossover, which it would of been if they use the same scale for both.

 

[273]

Thank you for all the idea's! I'm going to play with them one by one, and see if something fixes it. I for sure have came to the conclusion I need a bigger and solid roller cam if I want to play in the 6500+ RPM range anyway. The car is such a hoot to drive now not sure I want to do that in fear of loosing low end and possibly the EFI not playing well with the cam. I never meant for it to be a drag car just a fun stick shift street muscle car, and that it is.

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When you had it dyno’d did they say anything about performance at 6000 rpm + ?

 

[Newbomb Turk]

Use to assuming that 5252 rpm is at crossover, which it would of been if they use the same scale for both.

That’s only IF the HP and TQ scales are on the same side of the graph.

If the HP is on one side and TQ on the other will never cross.

 

[PRH]

Regardless of what the graph “looks like”, HP & TQ are always equal at 5252 RPM.

 

[Newbomb Turk]

Regardless of what the graph “looks like”, HP & TQ are always equal at 5252 RPM.

That’s true and I never said anything other than that.

What I said was on a GRAPH, the lines WILL NOT CROSS if the torque and horsepower are on the same side of the graph.

I tried early on to not have the curves cross because they look different not together but I got sick and tired of trying to explain why two stupid lines don’t cross on a graph.

 

[PRH]

“Give the people what they want”

 

[fishmens67]

“Give the people what they want”

Is that the same as the customer is always right.
When he's paying $150 or so an hour I guess he is. lol

 

[Newbomb Turk]

“Give the people what they want”

lol yep. Trying to explain it just wasn’t worth the squeeze. I had a guy tell me it’s his quick way to validate the numbers.

I said that tells you the graph is correct. Doesn’t mean the numbers are.

 

[fishmens67]

Get it figured out yet?

I gave him a diagnosis in post #12

 

[autoxcuda]

Thank you for all the idea's! I'm going to play with them one by one, and see if something fixes it. I for sure have came to the conclusion I need a bigger and solid roller cam if I want to play in the 6500+ RPM range anyway. The car is such a hoot to drive now not sure I want to do that in fear of loosing low end and possibly the EFI not playing well with the cam. I never meant for it to be a drag car just a fun stick shift street muscle car, and that it is.

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If you are happy with the way it drives and performs.... leave it alone.

What is the fascination with 6500rpm? It's just a number.

Would you be happier making the same HP and TQ at 500 more rpm than you do now? If so, you'll need more gear and you will just be tougher on your parts, especially valvetrain.

 

[Newbomb Turk]

If you are happy with the way it drives and performs.... leave it alone.

What is the fascination with 6500rpm? It's just a number.

Would you be happier making the same HP and TQ at 500 more rpm than you do now? If so, you'll need more gear and you will just be tougher on your parts, especially valvetrain.

I agree. If you like RPM, try 8500.

6500 is street/strip stuff.

 

[M_Body_Coupe]

SpeedPro - HT2011R LIFTERS, Anti Pump-Up, before I went to a hydraulic roller I ran these on all my flat tappet builds, each time my foot was the rev-limiter!

Setting these up with 0 (ZERO) preload is the key - which is what they are meant to do.

 

[Ceedawg]

SpeedPro - HT2011R LIFTERS, Anti Pump-Up, before I went to a hydraulic roller I ran these on all my flat tappet builds, each time my foot was the rev-limiter!

Setting these up with 0 (ZERO) preload is the key - which is what they are meant to do.

Yes Yes, adjustable rockers, Isky prefered, zero lash (pushrod stops turning) Crane anti pump up lifters. I was going 118, 4.88 gear and 29.5 slicks 6800

 

[fishmens67]

Setting these up with 0 (ZERO) preload is the key - which is what they are meant to do.

just off the retainer, not quite zero but close

 

[Illahe]

Hello all,

I have a 1972 Demon 4 speed, 3.91 gears, with a LA 410 CID stroker, it's 12.3-1 Comp, Ported Eddy heads with 2.055" intake valves, Hughes 242/246 @0.050 cam with 0.587/0.592 lift with Hughes 1.6 shaft rockers, Hughes PN 1129 springs installed with 145# closed pressure and 360# open pressure. Eddy Performer RPM intake port-matched, TTI Step headers with dual 3" exhaust with X pipe and a Gen 1 FAST EZ EFI, FBO Limiter plate in the Dizzy running 20 deg initial advance with 30 deg total. I built this motor about 7 years ago and it has never wanted to rev past 6000rpm I always thought it was a problem with the old Mallary High Fire 6 that was on it (rev limiter set to 7000 in both the High fire and in the EZ EFI). The car Dynoed 416 RWHP and 475 RWTQ so it has always been allot of fun to drive. But I finally got a wild hair and removed the High-fire 6 and installed a NEW FBO box and new coil, and the car idles better on the FBO and seems to have better throttle response but still falls on its face at 6000 rpm. Attached is the Dyno Chart, you can see it droppes off hard like it's hitting a rev limiter. Anybody have experience with a set-up like this with a problem reving? Could be valve float? Performer RPM just cant flow enough? Not Enough cam? I have thought about going to a solid roller the lighter solid lifters may kill 2 birds with one stone...

I know the A/F is kind of all over the place but the old EZ EFI only allows 3 Target A/F , Idle, WOT, and Cruise. No provisions for A/F based on RPM it just tries to reach the target A/F at WOT does not seems to do the best job of it... WOT set to 12.8-1 A/F...

Any help will be appreciated

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