I'm considering these lobes for my build. Wanting to turn some RPM (7500ish), TFS heads, LS3 valves, Holley Hi Ram, etc...

Anyone have any experience with these?

 

Wow! Those are LS lobes?!?!?!?

Why not just go LLSR?

Anyway.....if those are LS lobes, I'd get those TFS heads ported (Frankenstein?) by someone who will get them to build flow pass .750" lift. Otherwise, that high lift will be more of an impediment than a asset.

KW

 

I don't think they're LS specific lobes, but the LS uses a large enough journal to be able to use them. Without looking back at the catalog, I think the LS lobes is the R designation. I think I would have to commit to using a .750" wheel if I do decide on these lobes.

I'll take care of the porting on these heads. If I were to have someone port them for me, I would prefer to use some of the local talent like Greg Good or Rick McConathy.

I don't buy the idea that you can't use a lobe with more lift than your heads can flow to. To me, there doesn't seem to be much going on at peak lift in an engine. The highest pressure differentials are at low-mid lift points. Area under the curve is more important. A 230 lobe with .700" lift will have more area under the curve than a similar 230 lobe with .600" lift, generally speaking. I think that will make more power as long as the valvetrain is happy.

 

pretty cool...what ya thinking the 978/982 lobe combo for your 370 incher ??

 

Actually yeah, that's exactly what I was thinking lol.

I'm leaning more towards the HUC lobes just for the sake of simplicity. I don't even know if I would have the retainer to seal clearance for a .750" lift cam without going to a longer valve or +.050" retainers/locks.

 

I know what you mean about making sure everything fits without interference...I've used the +.050" stuff a bunch on roundy round builds
That's also a LOT of lift for a hydraulic lifter to deal with.....the spring pressure needed to keep the link bar lifter (heavier) as well as the thick *** pushrod in check with a lobe shape that basically KICKS....might as well be in the solid roller territory......
with that being your aluminum engine, a 240/248 LLSR set to zero lash would be quiet as all hell AND rev cleanly to your 7500 target rpm

 

I've considered a solid roller, but I'm not sure I want to incur that cost. This was supposed to be a budget build and I gotta stop the snowball affect somewhere. I plan to use roller tip rockers so I might as well go big on the lift, but not to where I need Jesels.

I'll probably stick to the HUC lobes and a 1.8 rocker.

 

HUC lobes work very well. Weren't they designed for speed boat racing? So they are stable.

 

Exactly, they're based on the Xtreme Marine so they are very easy to control. However, Comp says these DTL lobes are meant for high lift and high RPM, but also a .750" roller.

 

 

Definitely not for the faint of heart!

KW

 

I am not sure I understand your thinking here. You want to stay hydraulic to avoid the cost of roller rockers, but you are choosing a lobe with .750" lift which is not compatable with a stock rocker arm.

Just call Kip and have him make you a lobe that will be optimal for your RPM range while maxing out whatever lift you think you can pull off with a stock rocker? Why mess with catalog lobes? He does it for free which still amazes me.

 

You should.

Those lobes look pretty fast have you talked to Erik about it.

 

I'll be using aftermarket rockers one way or another, so I would like to take advantage of that and run a lot of lift that a stock rocker normally couldn't/shouldn't. The roller rocker options for hydraulic rollers are still economical versus the shaft rockers that most people run for the solid stuff.

 

No, I sure haven't. We discussed other lobes a while back, I think these DTL lobes are relatively new. They're certainly not as popular as LSK/XER lobes

 

I don't know if you have seen the post of the 440" stroker with Dart heads and LLR that made 780 horsepower, but that engine had Harlan Sharp rockers on it. What type of rockers are you planning on running with the hydraulic?

 

I'm wanting to use a steel rocker arm, so I'm looking at the Comp Ultra Pro Magnum Rockers. They're under $350 from Tick. Even without the big steel adjuster, I'm sure they're heaver than aluminum rockers, but I don't think I'll have to worry about trunnion failures, fatigue cracks, or clearancing the valve cover rail.



I supposed I could use those rockers in the stud mount configuration if I were to convert to solid roller. At that point, I might as well ditch the EFI and coils and put a carb and distributor on there too lol.

With those rockers, a PAC spring kit, 3/8" pushrods, Caddy lifters, and the cam, I'm looking at just under $1600 including shipping.

 

You've had good luck with the Caddy lifters?

 

Personally, I've never used them. I've heard recently about someone who swapped out another highly respected brand of lifter for them and picked up some considerable power after peak. Apparently, there's a bit of a "trick" to get them to work.

For ~$250, I thought I'd give them a try.

 

KCS, have you read this buildup? Stock rockers and lash...Patterson is no joke when it comes to engine building
http://www.enginelabs.com/engine-tec...-stock-racing/
This pic is interesting to say the least...