Swapping out my 6.0 shortblock and need to replace my MS3 because it has some bad lobes on it.... I will be running 243 heads for now with a single plane and 850 carb but would like to swap to 823 heads maybe next year.
So basically my question is has anyone ran say a stage 3 or 4 ls3 cam with cathedral heads? Does it really make that much difference if it’s designed for cathedral or rectangle heads?
thanks

 

I would go with something milder then. Ls3 heads do not need as much cam. Something like 227/237. If you overcam it for the cathedral heads it will be a turd with the ls3 heads.

 

A good stage 2 cam should work. BTR, Cam Motion or Tick

 

I guess I should have mentioned for this particular car I want the biggest cam I can possibly get, it’s just a weekend toy and needs that nasty cam lope to make up for the horrible patina and trashed interior lol
Was looking at this one or something similar
https://www.summitracing.com/parts/sum-8711/
but didn’t know if The 243 heads would like it for the time being...
car has a 4000 stall so it pretty much never sees below 3000rpm unless it’s idling lol

 

Ok then go 268/280-106+2. It will lope like crazy and run like ***.

 

Yeah who cares how it actually runs??? Long as it SOUNDS bitchin!!! LOL

 

As for 243 vs LS3 heads...I saw a facebook post where two friends built their cars. One used a Fast 102 and ported 243 and the other used LS3 heads and LS3 intake. The Fast 243 combo beat the LS3 by 2 hp. The LS3 would probably win with a bigger cam and higher rev limit. But under 7000 rpm, not much of a difference.

 

Ls3 heads do not like as much overlap as cathedral. Better to slightly undercam and be in good shape for the ls3 heads. Over 3 degrees overlap it will chop. You can also tune your adaptive spark to make it chop harder. Or give it a small vacuum leak to make it chop at idle.

Point is, cam it for how you want it to drive. You can MAKE it thump.

 

Lol guys I’ve been around long enough no exaggeration needed, I just don’t want a baby cam. I’m not flycutting so that would be my limitations on cam size. The ms3 drove great actually but I’ve been told that cam won’t work with ls3 heads. Because of the valve size, so just wanting to use the largest cam for 823 heads temporarily on 243 heads.....

Thanks for your input!

 

How would something likea BTR LS3 "NA Engines" Stage III 229/244 .615/.595 113+4 work? I've read of similar cams used with 243's

 

Im running that cam...its hauls ***

 

I’ll say this. Optimize the 243 setup, and you likely won’t care about going to rectangles. Not much of a difference unless your going to change everything when going rectangle.

 

Your probably right, I was actually VERY happy with the stock 243s on the lq4 with the MS3 cam. Now ill have 100lbs less weight and flat top pistons so Im sure it will be more than enough...

that BTR LS3 "NA Engines" Stage III 229/244 does look pretty nice

 

Call a reputable cam company and ask a expert... Why ask here

 

Like our high lift asa cam. ;-)

 

 

 

So far we have had 2 combos with stock heads at 410 and 430 rwhp on ls1s and over 400ft lbs of tq also. Thats pretty impressive if you ask me.

We have sold a few to rect port guys but no dynos/info on them sadly.

Why go more aggressive when a smaller cam will do the same work?

I mean, we have the Trex if you want all the lobe ;-)

 

well..... I went out on a limb ... kinda

Although I am seriously about to convince my boss at work to do the high lift ASA since he wants more street maners

not many reviews on this cam yet but just ordered it through summit for $272.99 since they have a $25 instant rebate right now..... I cant believe there THAT CHEAP.....
https://www.summitracing.com/parts/sum-8702
For that price if I decide to switch to Rec port heads later ill just sell it if it doesnt have enough clearance.

Also went ahead and ordered another set of lifters from WS6store, still got the headgaskets and bolts left over from my last order so as soon as this cam arrives im assembling the motor and will get some 1/8th mile times for yall to see what happens lol. Well the times will suck unless I can borrow some tires that will hook, but I can see what it will MPH anything over 90 and ill be happy.