To break a solid lifter something was wrong with your valvetrain geometry.

If I was gonna build a 500rwhp 348ci LS1 it would be hydraulic, use R lifters, titanium valves, big single springs, LS6 heads (for now), and a cam something like 240/244//112/+2 or +4, FAST LSX intake (if they produce), and the combo would need be shifted at 7200 or higher because it would be somewhat peaky.

 

Denny-
I agree, the geometry was right, although this generally wont cause broken lifters. however, it seems a lot of people "overkill" on springs. Either way, its in the past and doesnt matter. When it comes down to it(as you know) SRs arent going to be as reliable, but I think you got the very short end of the stick

PSJ-
"a stronger point". WTF are you talking about? I wasn't making a point. I am not "lucky", I could care less if you link this to "your site"

You are right, LS1s are making good power because of R&D, but the main matter at hand is the heads are awesome, which I clearly stated above.

as far as the dyno queen comment, I have been involved with TOOONS of big power head/cam and cam only cars. I have watched shops dig every last HP they can out on the dyno, but many "tricks" that dont translate on to the race track.

It doesnt really matter, I never argued with the fact that LS1 are fast, but with all the latest "X23325 cam is better than Y3263263 cam" shops are pushing things to get dyno numbers. I know this, for a fact. I have seen it done.

 

Take it easy Jordan, push that pulsing vein back into your forehead. Your comment was flamey and it drew flame.

S Quinn has done some neat things with LT1 hydraulic setups.

 

one thing to remember, a Lt1 is just a SBC. And there are tons of 550-600rwhp SBCs running around, all it takes is somebody that wants that kinda power to put the heads on a Lt1.
like mind games ~586rwhp 137mph trap street LT1.

 

Sure the big secret is no secret:

Something like they say in real estate only it’s: Heads, heads, heads. And oh…… did I forget to mention heads?

I’m still curious if anyone has really big 220-227cc good flowing heads using a moderate (say 230-235 or duration on a 110-112) cam as to what dyno results they have. Particularly above 6000 rpm.

Also I agree with Jordon regarding the LSx cams. It’s all the 2mx or the 3yp grinds. So just what does all that mean except they want to keep it a secret.

 

imo, get some 18degree heads, run a small cam.. smoke LS1s all day long :-D

 

Airflow=Hp so yeah a 300+cfm LS1 head is going to do a tad better than a 270cfm LT1 head. Chambers are better, valves are lighter, by a good amount, hell the whole valvetrain is much lighter.

Intake pulse tuining might have a HUGE thing to do with it also, just a guess. 3" runners vs 8" runners, not much of a contest. The sad thing is that GM had the technology to do the LS1 intake back in 92 when the LT1 came out because they used it on the Northstar.

Seems to me that the lowly HR Cartex setups seem to run some good numbers. 460rwhp and 10.60's @ 130 on a 346 cube motor. I've seen some big cube SR LT1's with more rwhp in like cars not beat that.

As far as heads being that big Denny, not on a 355, and only with the rest of the system being right is a 225cc (for a 383) head going to work well (and drive well) on a street car.

On to the camshafts.....

Look into this more before you go saying that a hyd roller is a weak lobe vs a solid roller. The only problem with comparing SR to HR stuff is that the total duration of the lobe is rated differently so we can't use that to compare them. So that's one thing to think about when you look at it. Another thing to think about is the lash differential from the HR to the SR and how that effects the velocity and acceleration of the lobe.

Anyways. HR vs SR has a lot to do with the duration you are going to run, and duration is directly linked to the RPM band you are looking at.

The less max RPM you plan to run the more aggressive the lobe can be. 7000+, 8000+, 9000+ and 10,000+ all require a different lobe to maximize the setup.

I really don't have the time or inclination to get out the graphs that show the lift vs duration of similar highly aggressive HR vs SR lobes and show the difference between them. We've beat that horse before. But in the durations right before the cross over point where SR's start becoming better than HR's. I've seen like .050 durations compared against each other on the same graph and the most aggressive HR lobe kills the most aggressive SR lobe out there, in lift and in lobe area (inch*deg). The HR lobe has more lobe area by over 4%. So much for the lowly HR lobe myth. At the cross over duration the HR lobe is equal in lobe area to the SR lobe.

BTW PSJ, I have some good pics and info on all of the FAST stuff from PRI.

If you want to smoke LS1's, you don't need 18 deg heads. A well ported 23 deg head can do that for you. You just need to make the rest of the combo better. Hell a 400 cube SBC based NA motor with 23 deg heads could put down 600rwhp @ 6500 if it was done right. Just a hunch.

Bret

 

imo, get some 18degree heads, run a small cam.. smoke LS1s all day long



yeah what he said

 

it doesnt take much to smoke your average cam or heads/cam ls1 the only n/a ls1 car that has pulled away from me hard was a 38xci ls6 vette.i want to be faster then everything else on the street so 38xci lt1 215cc heads, single plane intake or sheetmetal and you looking 600+ hp 650+ w/ a solid roller. and thats hopfully streetable(tuning)... them ls1 boys wont know what blew by um

 

I don't want to seem biased here...consider the fact that I don't
own, nor ever have owned an LT1/LS1 and it might help steer
this thread back onto it's original path:

Taking an LT1 and modifying it beyond it's OEM configuration will
smoke "Motor X" at various levels depending on the depth of change.

Taking an LS1 and modifying it beyond it's OEM configuration will
smoke "Motor X" at various levels depending on the depth of change.

Where are we going with this?

From the research I have done so far, stock vs. stock, the LS1 is
a stronger motor from idle to power peak pulling harder 0-60's
and 1/4 miles/trap speeds.

 

The point of my original post really had nothing to do with…. “my dog is bigger than your dog.” The intent however, was an attempt to understand why modified LSx’s with stock hydraulic lifters seem to rev so freely using moderate cams as compared to modified LTx’s using hydraulic lifters.

This was prompted by observing absolutely great LS1 top end dyno results using what has time and time again proven reliable……stock hydraulic lifters.

What I’ve gathered from the prior posts is it appears the secret is in the heads unless someone else has any objective information regarding the LSx valve train setup. In other words: a LTx car with the proper heads, proper lifters, proper springs and proper cam should be able achieve somewhat similar results.

 

I 'Think" I mentioned the Larger cam base?

This does have alot to do with it.

When I say base I mean if you tried to put your fingers around it the LS1 cam would be much bigger around on both the bearings and lobe section..

So While the LS1 uses the exact same lifter as the LT1 and L98(And LT4) they cam run a biger cam ramp and more duration because the lobe angle is not as steep and does not put as much stress on the lifter as the older smaller base circle cam shaft.

This makes the lifter act like it is running on a much smaller cam while delivering more of every thing at the same time. the 1.7 Rocker ratio does not hurt This makes the cam lobes physicly smaller to boot

Hopefully this helped some

OH YEAH! it does not hurt that the LS motor is just a flat out better desighn then the old SBC

 

Very insightful.

It appears those of us with stroker motors using a small circle base cam may be hurting ourselves then. I’m wondering.... with a 383, what are the variables that make running the small base cam unnecessary? If that were true…… then could it be potentially better to run a 383 vs a 396 for the larger cam base?

It my understanding you need a small base cam for a 3.875 stroke but under the right conditions one isn't necessary for a 3.75 stroke.

 

Denny, you have little choice in the matter because of where the cam is positioned in the LT1 block. What we need is someone to make an aftermarket tall deck LT1 block and then we can get more cubes out of the thing and not worry about having these cams ground on small base circles the way we do.

 

Dennt if you are having to run a small base on your motor it is more then likly the correct rods were not choosen or they were not prepped for your application

I know quite a few 396 cars running normal base on there cams