From a solid roller to hydraulic roller

[Tom Walker]

Would think you need to shrink the duration substantially to get a substantial difference in street manners.
May require 20-25 degrees less duration to achieve what you are looking for.
All personal preferences, so you are the final decision maker as to what is acceptable for drivability on the street.
Good luck and would been interested in what you choose and how you like it.

[skinny z]

Can you find out the overlap triangle between the two cams? There may be a lot more area change than just looking at .050 duration and total lift would suggest. And there may not, lol. But I suspect a milder hyd/roller isn't coming off the seat near like an aggressive solid/roller so the overlap triangle could be reduced by quite a bit.

Now this is the kind of info I am looking for. Something that makes me dive in deeper. The slower open ramp on the intake side, and slower closing ramp on the EX side. Is there an online Program or software that can show how balanced they are? And should they be perfectly balanced? Originally I had a 1.8 rocker on the intake but never retarded my cam on the Dyno to "make up" for the quicker opening rate. I bet there was some power to be found, if it was at the correct IN centerline to begin with.

I would say the conversations surrounding overlap and IVC are valid ones.
Realistically, where do you want your peak HP RPM to land?

As for an on line program?
viewtopic.php?t=63025

[CamKing]

(and I am not here to debate the LSA.

So, you want to fix the problem, without addressing the cause of the problem.

[Orr89rocz]

My current cam is VERY torquey, just in the wrong RPM range. It wants to spin to 7000+, even in a 540.

You said it peaked at 6100? Thats about right, its not wanting to go to 7000 plus.

About same size cam as mine in my 555 except i have more lift and its on a 109 lsa. Very streetable but mine is port injected efi. Similar rpm range.

You mentioned it cruises good, but something happens when you try accelerate abit? Sounds like a tune issue to me, whats the air fuel and timing doing here? It got better with plug wires? Even more so an indication of tune i think

Its common for late model guys running big cams in stick shift cars, low rpm drivability can be poor unless tune is spot on with fuel and timing

[F-BIRD'88]

Buy and install Lunati /Voodoo /UdHarold designed
Solid Street Roller cam #40110732
If you want a custom grind version that will drive even a hair nicer. order this same cam ground on a 112 LSA
Install on 107/117 centers.. Set the lash cold about .012"-.014" cold.. Its a tight lash cam.

If you want the Fbird/Troll cam version just pick up the phone and order it on 112LSA at Lunati Cams.
Someone is waiting by the phone there for your call.

It will run great and make very decent street power.
More than you'll ever use on street tires.
Enjoy...
You won't need to chase the valve lash with this one assuming the rockers are not worn now.

Could back off on the spring force and enjoy extended street service life..
I'd ditch the 1.8 rockers..

[Bishop540]

(and I am not here to debate the LSA.

So, you want to fix the problem, without addressing the cause of the problem.

Can you prove that the LSA is the CAUSE of the "lack of low torque"? Or would it be easier for you to say that the valve events are wrong? Dyno, after dyno shows the wider the LSA gets the wider powerband gets, and torque goes down unless you increase compression to compensate the loss of torque and wider LSA.

I have already paid for a custom cam earlier this year, another solid roller with more lift, especially the exhaust .715/.733 . I questioned why he was gonna make the cam on a 112lsa, and almost the same duration numbers I had before. He said my timing events were all wrong with the current cam and I had too much overlap. Fine. After he placed the order on the new cam he told me to change my 10yr old springs, understandable. But then he went on to say I needed more compression (up to 11.2) and that it would need to rpm higher up to 7000. The total opposite of what I asked him to do!!!!!! I wanted to keep my 10:1 shortblock as-is, no crazy milling to my heads (to eek out less than half-point of compression) and I wanted a cam that would peak at 6100, shift at 6500. What's so hard about that for a cam designer? He was more concerned with peak power at a higher rpm. Now I am stuck with a nice billet with a press-on gear that I will never use until I raise the compression and upgrade crank to a forged. Not what I wanted!

So please prove to me why I need a wider LSA when I ask for a powerband that ends at 6100? If I wanted to spin it higher than 6100, then I would be all-ears. Thanks!

[Orr89rocz]

There is no way that thing is lacking low end torque

[CamKing]

So please prove to me why I need a wider LSA when I ask for a powerband that ends at 6100? If I wanted to spin it higher than 6100, then I would be all-ears. Thanks!

No need, you have it all figured out.
I'm sure Comp has a "Thumpr" cam that's just what you're looking for.

[CamKing]

There is no way that thing is lacking low end torque

Exactly. What it's lacking, is a broad, flat torque curve. With 540cid, peak torque isn't the issue.

[CamKing]

so he put a Jones hydraulic roller in it. 241-248 .640 or so lift, on a wide 114 lobe sep. It idles and drives like a kitten, drives really well, and still made 730hp, tq is still a non issue, or I should say it's still an issue, because it makes a lot more at lower rpm, and it had traction problems before too.

That must have been a fluke.

[Bishop540]

Buy and install Lunati /Voodoo /UdHarold designed
Solid Street Roller cam #40110732
If you want a custom grind version that will drive even a hair nicer. order this same cam ground on a 112 LSA
Install on 107/117 centers.. Set the lash cold about .012"-.014" cold.. Its a tight lash cam.

If you want the Fbird/Troll cam version just pick up the phone and order it on 112LSA at Lunati Cams.
Someone is waiting by the phone there for your call.

It will run great and make very decent street power.
More than you'll ever use on street tires.
Enjoy...
You won't need to chase the valve lash with this one assuming the rockers are not worn now.

Could back off on the spring force and enjoy extended street service life..
I'd ditch the 1.8 rockers..

The PRW 1.8's are gone. They proved to be junk on 600lb springs. They were ok for my old hydraulic engine but not anything with more lbs. I now have Shaub's AFR (Harland Sharp) special designed for the weird stud angle of an AFR head (version 1 head, S1 head I believe)

I do have UDHarold's 502A5. That's what I have now. Its just under a Lunati part number now-a-days. I found that out a couple years later, and then did some research about the cam. He did say it was a race cam that could be driven on the street, but it would be a bear. He is so correct. Here is some of the info I found a couple years later: https://www.chevelles.com/threads/udhar ... am.108663/

One day I will use this SR cam to its potential: high compression, high stall, etc...just not on a street engine. It ran well at the track but thats where I noticed I needed lots more compression and stall - not a lot of low torque when my car hooked on that sticky track. Needed more stall than what an OD trans/torque convertor could provide. On the street, even with ET Streets, it just spins -but moves with the stickier tires. On street tires it wouldn't be good at all.

[Bishop540]

So please prove to me why I need a wider LSA when I ask for a powerband that ends at 6100? If I wanted to spin it higher than 6100, then I would be all-ears. Thanks!

No need, you have it all figured out.
I'm sure Comp has a "Thumpr" cam that's just what you're looking for.

Pride comes before the fall my friend. I am here to learn, not to prove I'm right and your wrong. You have all the experience, not me. I just want to learn the WHY of all the myths. If someone cant prove it then they probably don't have any idea WHY. With all due respect...

[Bigchief632]

so he put a Jones hydraulic roller in it. 241-248 .640 or so lift, on a wide 114 lobe sep. It idles and drives like a kitten, drives really well, and still made 730hp, tq is still a non issue, or I should say it's still an issue, because it makes a lot more at lower rpm, and it had traction problems before too.

That must have been a fluke.

Yeah, I'm sure it was a fluke. No, honestly, I didn't expect it to make as much HP as it did. Your cam worked very well, even though it's totally wrong, and has waaaaay to much lobe separation.

[Bigchief632]

So please prove to me why I need a wider LSA when I ask for a powerband that ends at 6100? If I wanted to spin it higher than 6100, then I would be all-ears. Thanks!

No need, you have it all figured out.
I'm sure Comp has a "Thumpr" cam that's just what you're looking for.

Pride comes before the fall my friend. I am here to learn, not to prove I'm right and your wrong. You have all the experience, not me. I just want to learn the WHY of all the myths. If someone cant prove it then they probably don't have any idea WHY. With all due respect...

The wide lobe separation, flattens the TQ curve, makes more on the bottom without the big hump in the middle, and carries farther, all else being equal. Not to mention better idle, drivability, fuel efficiency etc. In the example I gave you on the first page, that engine also picked up almost 60ftlbs at 3600, the lowest point tested both times, and lost about 20 in the middle and at peak It still made peak power around 6400, 6800 before, but obviously carried farther with the extra duration. All in all, a great "street" combo. Not to mention, as the cubes grow, the TQ increases by default. So it's pointless to try and make more where you can't use it all anyhow, and then have it fall off hard above peak. Not to mention reduce fuel economy, reduce manifold vacuum, reduce smooth drivability as well, pretty much achieving exactly OPPOSITE of what you want for a true street car. Especially one with an overdrive, and ac.

[F-BIRD'88]

Yes I was aware that the cam u have is the 502A5lun cam... Unfortunatly Harold has now passed.

When looking fir a new better street cam for you my instinct was to go for the milder 502A3 lun UDharold street strip cam.
Its also a UDharold Ultradyne cam.. (now offered by Lunsti)
But I'd really like you to tame it down just a hair more for driving in OD gear.. Thus the UDharold designed Voodoo #60232. new #40110732.
I'd really like you to take it a little step further and call Lunati and custom grind order this Voodoo cam on a 112 LSA..
Its easy and they like making custom grind cams for their customers.. Just call and ask.

The car will be much happier when driving in OD gear.
It will make a ton of street power right where you want it.
It does have a good 1½ to 2 step tamer driving nature.
It is a high perf street cam.. It will love nitrous also.
Your chevelle posts mention nitrous..
The 10:1 cr is just right.
As said the carb and diz may well need further fine tuning also..

With your tall tires and 3.73 street gears and a Overdrive trans. This cam will work much better overall while still making great power and torque.
I believe if UD Harold was still with us he would be steering you in this direction for a much better camshaft for how you use your car.

Did you know that the guy who runs the Lunati cam custom grinding shop is UDharold's old U D cams company "right hand man" ?