What lifters are you planning on using? I'm round up parts for my small bore ls7 heads build and can't decide which solid roller lifters will work with over 700 lift at 8k rpm and not lose oil pressure without bushing lifter bores which I read happens (see the quote below. He is talking about solid roller lifters, in a discussion about oil pressure issues with solid roller lifters). I wonder if Katech keeps lift under .680 on the cam they sold you and making duration wild, for that reason.



In the same thread they were discussing the differences in design of various solid roller lifters. I wonder which brands (if any) of solid roller lifters for the LSX, have addressed this issue that Louis is speaking about above, and tested their lifters with camshafts that have over .400" lift at the lobe/lifter.

 

RACECAR!!!
What I have noticed is that it is not a solid vs hydraulic thing so much as a dedicated axle oiling thing. Example - Johnson LSR2126ST are hydraulic have the axle oiling hole, and you see guys running 25-30 psi at idle vs typical 35-40. Never bothered me, because any rpm at all (say 1200 rpm cruising) and pressure is up over 40. I went from those lifters to solids and saw idle pressure increase. After I built a bigger motor, also on solids, crazy good idle oil pressure. But the next time I tear into it, i'm going back to the axle oiling, and I expect i'll see the pressure drop. i could be dead wrong on this, but I thought I'd mention the observations.

Seen it first hand on three different vehicles, so that means it's scientific and indisputable, right?

 

I hear you about the axle oiling bleeding more pressure away. But in that thread from the vette forums where I quoted Louis at LG Motorsports mentioning the orifice in the lifter bores being uncovered, and different design lifters causing it, is a whole separate issue. And now that I just read it over again and thought about it, if he's saying small base circle cams, then it's not the amount of lift in terms of how high the lifter comes out the bore, it's the opposite, the lifter going down too far in the bore because of small base circle cams, and the design of the lifter is uncovering the larger oil hole in the lifter bore.

 

I am leaning towards the .937 lifters because I'm planning on running a C5R block. My manifold is a custom aluminum intake manifold. I do have a lead on a ITB Kinsler manifold though, so I may go that route as well. I was actually planning on going with a much larger camshaft but they reccomend the one I purchased for my application, plus I plan on using this motor for rocky mountain race week so maybe a smaller cam was a good choice as far as reliability is concerned.

 

That makes sense. I had not thought of that. Interesting

 

Here's the Cam spec sheet from Katech

 

What is everyone's opinion with this cam, I've never seen one that looks even remotely close to this one. Especially with rounded edges. Was that designed for more meat on the cam to be a bit stronger with the big valve springs and the solid roller combo? Also looks like maybe ot was Titanium Nitride coated maybe? It was designed for 24 hrs racing series. I've noticed these C5R parts are exceptionally well engineered and manufactured to a very high standard. Would love to hear some comments

 

The way that cam looks is the result of grinding into the base circle, or the actual shaft diameter. Gonna need longer pushrods fer sher...

 

Definitely, it is a very small base circle, which explains how it gets it's big specs. Also feels much heavier than a standard ls cam. Not too sure on material

 

For anyone searching for the mounting hardware for the rocker assembly, here are the part numbers:

There are option for grade 8 bolts or ARP 2000 bolts to hold the rocker pairs down to the stand.



BLT-21891-16 STAND BOLTS $46.00

BLT-21750-24 GRADE 8 SHAFT BOLTS $27.50

BLT-21756-24 ARP SHAFT BOLTS $160.00

 

The cam core is probably not hollow due to the shorter base circles

 

where did you find these heads? also whats the runner size? i know i can search this info but didn't no if they got hogged out more

 

Facebook marketplace and came with the intake manifold

Everything else was from katech.

 

another example of where flow numbers dont mean everything

 

Insane flow through a 210cc runner

 

Pretty serious flowing heads

 

not saying they dont flow, but people always want to see over 400 cfm somewhere. but yea on a 210 runner the numbers are ridiculous. i basically meant to say something along the lines of, "these 380 cfm will outperform most heads that produce over 400 cfm" so another example of where final flow numbers dont mean everything

 

Yea I understood your comment and completely agree

 

Here here. My post was agreeing with yours.

 

yea it seemed like it could have went either way lol. im sorta envious of these c5r heads, but problably just because my car is having its issues