[slowbird]

Originally Posted by Dragncar

You would want more than a 9 deg split ?
The Comp had a .264 intake so it had a 10 deg split. But the intake lobe Tim Thought would work best had 265 @ .050 and he thought it was fine.
The Comp cam had .759 gross lift, .741 net lift.
My heads are done at .700 lift for all intents and purposes. 350 cfm at .700 and the only go up 9 cfm, 359 cfm at .800 lift.
So I did not see the point of hanging the valve so much when it was not going to get me anything.
Jeff at KRE said Super Stock guys open the valve way past where the heads flow all the time but its harder on things.
Not what I am after.
Just trying to open the valve enough to matter, run the biggest lobe I can with a margin of safety.
Some might have the balls to run a bigger cam in a stock block, but I just bracket race. I got away with .688 lift for years in a stock block so .731 lift is a nice jump. I know you can run a .457 lobe in a stock block like Jake ran with his SB cam but the duration was in the .250s.
Still should be close to 700 HP.

Like I said just my opinion.

[Jay S]

Originally Posted by Dragncar

Does 2228/4267 get you what you are after ?

Thanks.. It had a HXL series profile on the intake. Definitely aggressive.

The exhaust side had a RZ roller in it. That is much less aggressive, about the same as the Bullet, probably even a touch gentler.

It would be interesting to see the velocity chart like Stan show between the two.

[Stan Weiss]

Originally Posted by Dragncar

You would want more than a 9 deg split ?
The Comp had a .264 intake so it had a 10 deg split. But the intake lobe Tim Thought would work best had 265 @ .050 and he thought it was fine.
The Comp cam had .759 gross lift, .741 net lift.
My heads are done at .700 lift for all intents and purposes. 350 cfm at .700 and the only go up 9 cfm, 359 cfm at .800 lift.
So I did not see the point of hanging the valve so much when it was not going to get me anything.
Jeff at KRE said Super Stock guys open the valve way past where the heads flow all the time but its harder on things.
Not what I am after.
Just trying to open the valve enough to matter, run the biggest lobe I can with a margin of safety.
Some might have the balls to run a bigger cam in a stock block, but I just bracket race. I got away with .688 lift for years in a stock block so .731 lift is a nice jump. I know you can run a .457 lobe in a stock block like Jake ran with his SB cam but the duration was in the .250s.
Still should be close to 700 HP.

Troy,
Yes, there is a good reason for Intake cam lift above max flow as long as the port doesn't backup. If we ignore the effects of wave tuning. And just look at piston flow demand. The point of max piston flow demand is around 73-77 degrees ATDC depending on stroke rod ratio. So what is your cam lift and head flow there?

Stan

PS Let me add about Exhaust. One thing almost never talked about is what is your exhaust valve lift ABDC.

[Steve C.]

Related ?

"Unlike a hemi or a typical 4-valve-per-cylinder type head, a parallel (or nearly so) 2-valve cylinder head typically continues to flow more air up to lift values equal to as much as 0.35-0.4 times the valve diameter. The reason for this is that there is a flow pattern transition period that takes place at a lift value of about 0.25 of the valves' diameter. When this point is passed, if the port has been modified to support flow in this lift region, the valve efficiency actually starts to increase. This is the reason why a 2-valve engine responds to high lift."

David Vizard


.

[Dragncar]

Originally Posted by Jay S

Thanks.. It had a HXL series profile on the intake. Definitely aggressive.

The exhaust side had a RZ roller in it. That is much less aggressive, about the same as the Bullet, probably even a touch gentler.

It would be interesting to see the velocity chart like Stan show between the two.

Here are the 2 cam cards.
Let Stan do what he does and see how they stack up.

[slowbird]

Originally Posted by Jay S

Thanks.. It had a HXL series profile on the intake. Definitely aggressive.

The exhaust side had a RZ roller in it. That is much less aggressive, about the same as the Bullet, probably even a touch gentler.

It would be interesting to see the velocity chart like Stan show between the two.

The HXL lobe is a nice lobe, we've used it with good success. But never in a stock block

[Stan Weiss]

Originally Posted by Dragncar

Here are the 2 cam cards.
Let Stan do what he does and see how they stack up.

Troy,
I don't have any lobe lift data for any of those lobes. There is not enough information on the cam cards for me to do what I want. So I went to the Comp Cams Lobe Master Listing I have looking for 0.200" duration and the other number are a tiny amount different. The Exhaust is the same.

On the other cam card do you know if those are Bullet or UD lobes?

Stan

[Dragncar]

Originally Posted by Stan Weiss

Troy,
I don't have any lobe lift data for any of those lobes. There is not enough information on the cam cards for me to do what I want. So I went to the Comp Cams Lobe Master Listing I have looking for 0.200" duration and the other number are a tiny amount different. The Exhaust is the same.

On the other cam card do you know if those are Bullet or UD lobes?

Stan

It took Tim a little bit to find the lobe in one of his catalogs, but he found it.

I believe new cam is a UD lobe. He was looking for a proven safe lobe but something larger than the UD .4176 lobe I ran for years. I will double check with Tim.
Thanks for the information.

[Steve C.]

Tim used his Bullet lobes R299/4315 and R308/4315

https://www.bulletcams.com/Masters/Rlobes.htm



.

[Cliff R]

I don't know if there is a "proven safe lobe" to run in a stock block even with a brace in it. Keep in mind with the spring pressures required to control the valve action with these solid roller cams it's like having 16 fat guys standing on your pushrods. The side-loading is extreme with solid roller cams at the spring pressures we run on them aggressive profiles or not......IMHO.

Here I built ONE stock 455 block engine with a solid roller cam for full race duty and it last 11 runs before the lifter bores caved in and took out the entire engine.

Prior to that deal we had rebuilt and "upgraded" that engine half a dozen times. It came here first time with flat top SD pistons on stock rods topped with #48 heads and a Comp 292 Magnum cam in it. That engine BARELY busted the car into the 11's so the owner wanted some changes made to it.

The heads went to KRE for porting and they supplied a 260/260@ .050" flat solid for it. Added Crower rods and kept the SD pistons but put lighter pins in them. That put the car solidly into the 10's, but after a few years the owner wanted more so we went to a set of 330cfm early Edelbrock round port heads and a solid roller cam. That cam was 264/264 on a 110LSA but not overly aggressive. It really didn't run much faster than the flat solid cam so the owner opted for a larger solid roller cam 276/284 with over .700" lift. I did NOT like the change and insisted on a lifter bore brace, but it didn't help. We lost the lifter bores after 11 runs and took out the entire engine.

It wouldn't have mattered anyhow as the power level was exceeding the capabilities of the block. I found a couple of main cap dowel pins in the oil pan last time it was apart so the writing was on the wall before the lifter bores caved in.

We replaced that engine with a KRE 505 with High Port heads and it has survived nearly 20 years of HARD use with one set of springs and rod bearings rolled into it. We also had to upgrade to Crower Enduro rockers and 13 out of 15 of the Scorpion rockers were cracked.

Hard lesson learned with pushing the limits of the stock blocks. If I were still in the engine building business we'd very quickly go to an aftermarket block with that sort of engine. No solid rollers with PAC springs and super high compression would end up in a stock block for any reason, even if it was for drag racing purposes where it's only loaded 9 seconds at a couple dozen times a month. I'd just build an aftermarket block from the start and sleep a lot better at night.......

[Dragncar]

Originally Posted by Cliff R

I don't know if there is a "proven safe lobe" to run in a stock block even with a brace in it. Keep in mind with the spring pressures required to control the valve action with these solid roller cams it's like having 16 fat guys standing on your pushrods. The side-loading is extreme with solid roller cams at the spring pressures we run on them aggressive profiles or not......IMHO.

Here I built ONE stock 455 block engine with a solid roller cam for full race duty and it last 11 runs before the lifter bores caved in and took out the entire engine.

Prior to that deal we had rebuilt and "upgraded" that engine half a dozen times. It came here first time with flat top SD pistons on stock rods topped with #48 heads and a Comp 292 Magnum cam in it. That engine BARELY busted the car into the 11's so the owner wanted some changes made to it.

The heads went to KRE for porting and they supplied a 260/260@ .050" flat solid for it. Added Crower rods and kept the SD pistons but put lighter pins in them. That put the car solidly into the 10's, but after a few years the owner wanted more so we went to a set of 330cfm early Edelbrock round port heads and a solid roller cam. That cam was 264/264 on a 110LSA but not overly aggressive. It really didn't run much faster than the flat solid cam so the owner opted for a larger solid roller cam 276/284 with over .700" lift. I did NOT like the change and insisted on a lifter bore brace, but it didn't help. We lost the lifter bores after 11 runs and took out the entire engine.

It wouldn't have mattered anyhow as the power level was exceeding the capabilities of the block. I found a couple of main cap dowel pins in the oil pan last time it was apart so the writing was on the wall before the lifter bores caved in.

We replaced that engine with a KRE 505 with High Port heads and it has survived nearly 20 years of HARD use with one set of springs and rod bearings rolled into it. We also had to upgrade to Crower Enduro rockers and 13 out of 15 of the Scorpion rockers were cracked.

Hard lesson learned with pushing the limits of the stock blocks. If I were still in the engine building business we'd very quickly go to an aftermarket block with that sort of engine. No solid rollers with PAC springs and super high compression would end up in a stock block for any reason, even if it was for drag racing purposes where it's only loaded 9 seconds at a couple dozen times a month. I'd just build an aftermarket block from the start and sleep a lot better at night.......

That sort of thing is always in the back of everyone mind who does this sort of thing with a stock block.
It would suck if it broke. I do have a IA2 with 80% of the stuff already bought.
What brace did you run ?
That cam was bigger than anything I would try in a stock block. No PAC springs either but anything can happen.
I tried to sell the block but no one jumped so I put it together with a few upgrades.
Not even going to try getting it into the 9s.
I was temped to just run the same UD cam I ran for years and years. This cam is just a tad bigger.
But IA2s exist for a reason.

[Stan Weiss]

Originally Posted by Steve C.

Tim used his Bullet lobes R299/4315 and R308/4315

https://www.bulletcams.com/Masters/Rlobes.htm



.

Steve,
Thank you

Stan

[Stan Weiss]

Troy,
Since I don't have real lobe lift data for either of these cams this just a guess on my part. This is the 2 intake lobes.

Stan

[Stan Weiss]

Troy,
Again since I don't have real lobe lift data for either of these cams this just a guess on my part. This is the 2 exhaust lobes and they are almost the same

Stan

[Gach]

Originally Posted by Cliff R

I don't know if there is a "proven safe lobe" to run in a stock block even with a brace in it. Keep in mind with the spring pressures required to control the valve action with these solid roller cams it's like having 16 fat guys standing on your pushrods. The side-loading is extreme with solid roller cams at the spring pressures we run on them aggressive profiles or not......IMHO.

Here I built ONE stock 455 block engine with a solid roller cam for full race duty and it last 11 runs before the lifter bores caved in and took out the entire engine.

Prior to that deal we had rebuilt and "upgraded" that engine half a dozen times. It came here first time with flat top SD pistons on stock rods topped with #48 heads and a Comp 292 Magnum cam in it. That engine BARELY busted the car into the 11's so the owner wanted some changes made to it.

The heads went to KRE for porting and they supplied a 260/260@ .050" flat solid for it. Added Crower rods and kept the SD pistons but put lighter pins in them. That put the car solidly into the 10's, but after a few years the owner wanted more so we went to a set of 330cfm early Edelbrock round port heads and a solid roller cam. That cam was 264/264 on a 110LSA but not overly aggressive. It really didn't run much faster than the flat solid cam so the owner opted for a larger solid roller cam 276/284 with over .700" lift. I did NOT like the change and insisted on a lifter bore brace, but it didn't help. We lost the lifter bores after 11 runs and took out the entire engine.

It wouldn't have mattered anyhow as the power level was exceeding the capabilities of the block. I found a couple of main cap dowel pins in the oil pan last time it was apart so the writing was on the wall before the lifter bores caved in.

We replaced that engine with a KRE 505 with High Port heads and it has survived nearly 20 years of HARD use with one set of springs and rod bearings rolled into it. We also had to upgrade to Crower Enduro rockers and 13 out of 15 of the Scorpion rockers were cracked.

Hard lesson learned with pushing the limits of the stock blocks. If I were still in the engine building business we'd very quickly go to an aftermarket block with that sort of engine. No solid rollers with PAC springs and super high compression would end up in a stock block for any reason, even if it was for drag racing purposes where it's only loaded 9 seconds at a couple dozen times a month. I'd just build an aftermarket block from the start and sleep a lot better at night.......

You can lead a horse to water but you can’t make him drink

[Steve C.]

And if desired one can order and use solid roller cams that do not need a ton of spring pressure and have ramp designs that are easy on valve springs.

.

[Dragncar]

Originally Posted by Steve C.

And if desired one can order and use solid roller cams that do not need a ton of spring pressure and have ramp designs that are easy on valve springs.

.

Thats what I did.

[Steve C.]

The UltraDyne .4176 lobe mentioned in your post number 28 is a fine example.

Tim at Bullet Racing Cams said years ago they used to run it with a typical Small Block Chevy valvetrain mass with around 190 lbs seat pressure, in a Big Block Chevy at around 220 lbs.

And I'm not talking about in a Pontiac High Port head with large 2.200-inch diameter intake valves that are 6.200" long ! !

Inadequate oiling, excessive spring pressures and the hammering effect associated with VALVE LASH play a significant part in the failure of the roller, needle bearings and axle. BUT very important, the lack of adequate valve spring pressure to control the valves is a potential KILLER.


.

[Stan Weiss]

Interesting. How some people want to make all SRT lobes the same. They are not. Some will want more or less spring pressure than other ones. Interesting to watch a spin tron test and see most of the valve train problems go away when the springs are change to ones with less over the nose pressure.

Stan

[Gach]

Originally Posted by Steve C.

The UltraDyne .4176 lobe mentioned in your post number 28 is a fine example.

Tim at Bullet Racing Cams said years ago they used to run it with a typical Small Block Chevy valvetrain mass with around 190 lbs seat pressure, in a Big Block Chevy at around 220 lbs.

And I'm not talking about in a Pontiac High Port head with large 2.200-inch diameter intake valves that are 6.200" long ! !

Inadequate oiling, excessive spring pressures and the hammering effect associated with VALVE LASH play a significant part in the failure of the roller, needle bearings and axle. BUT very important, the lack of adequate valve spring pressure to control the valves is a potential KILLER.


.

Those High Ports with 6.200 long valves are very heavy valves, so what do you think. The seat and open pressure has to be to run .750 lift cam. Then add 1.7 rocker on top of that. Instead of a 1.5 or 1.6 rocker. Because thats what SD set them heads/springs up for.