are you talking LSA or LCA ? two different things .

There have been some very long threads on SpeedTalk about Vizard's LSA chart. Most engine builders think he is nuts although not everyone. I think the trick is that Vizard's chart was really only designed for 23 degree head SBC engines but I'm not sure. I do know that if you follow his advice you end up with cams that seem very strange and the cores might not even exist to make them. However, as Dwayne hinted at, some of the EMC guys had success running a super narrow LSA. I recall engines with 99, 100 and 101 lobe angles. That kind of stuff is way off the chart in my world. I used to have an old Crower cam that was 103 or something like that. I never ran it so now idea how well it worked. It must have worked at some point for someone though.

I'm not sure what I'm going to do with this engine. I might just put my old cam back in it or I might try one of these new lobes that Comp has released. The DGO 14669 looks like it would work on the intake for my engine or perhaps the DSP 12177. I think the DSS lobe might be pushing the lift just a tad too far.

Lobe displacement angle LDA. Lobe seperation angle LSA or lobe sep as i call it.

Ouch. Sorry to hear that...

It's not as simple as they make it out to be, but it's better than some crap I've seen published on the subject.

Many years ago the late Joe Sherman (who only recently passed away) had an article in Car Craft or Hot Rod where he did a 106 / 108 / 110 LSA comparison on a fairly hot (close to 600 HP) SBC 23* build with a solid flat-tappet cam. The 106 made more power & torque everywhere except the last couple of hundred RPM. The 110 never made as much anywhere as the 106; the 108 was the cam that made a little bit more than the 106 only at the very top of the RPM range.

It was valid for that specific build, but the YMMV caveat always comes into play.

There's my suggestion... but you have more time & $ than I do at this point.

Same kind of test i mentioned earlier, but with a sb mopar, i believe it was a 408. It was in enginemasters 2008 oct i believe. Ill have to look that up, but they found in that test of several different lsa spec'ed cams that the 108 was best in that combo. Best avg power. It was an interesting read as well.

You should always cam for the build, but with that said.

I think one of the reasons the old MP .590 does so well for A lot of people Even to this Day, is its 106 LSA, and its 271 @ .050. The 106 LSA helps in the lower torque range, and the 271 @ .050 gives it some upper HP range. A pretty broad range race cam IMO.

Ive even heard some early racers refer the Mp 590 cam torque cam compared to others in the race environment.

I see. I think it would interesting to go to one of davids seminars just to see his theories first hand . Thanks Andy.

Do you have all the specs of the .590 cam for BB? Open/close and lift both valves?

I've read that article a few times and I think it needs some editing for clarity. I don't think the author ever says how the cams were installed. Were they all installed straight up? He also doesn't talk about the big effect that LSA can have on valve to piston clearance. And I think some of his conclusions are wrong. He says the 101 LSA cam has a wider powerband but I think that is wrong. Looks to me like the 101 cam falls off faster than the others.

It is a spare engine so I'm not in any hurry to figure it out. I can leave it sit until I come up with another idea.

The thing about a wide lsa cam is they retard the intake lobe, & that will affect low end TQ, I have advanced a wide 112 lsa cam from 111 Intake LCA to 106 & it pick up lots of low end & still pulled on the top end, yes this was tested on a dyno.

The 101 does Fall off faster at the Top of the rpm, past 5600. I guess it depends on where you start and stop your power band measurements.

If you look at his dyno graphs, the 101 LSA did have the Wider Stronger power band up to 5600 rpm

Now if you compared the 101 LSA from say 5000 to 6500, clearly the other two cams had the wider power band. In this case, if you had a 5000 stall vert, the wider LSA cams would be the better choice. A 4000 stall vert, probably the 101, just by the visual of the graph. Didn't spec the numbers out. 1500 vert, the 101 Blows the wider LSA cams away.

With that said, wouldn't want the 101 LSA cam in my race car.



Edit, And Dave, yes I have the specs for the MP 590. I will post them up for you later.

Thanks. I know the dynomation 5 program is not very reliable to real world results, but just for giggles i input alot of cams in it using my 511 specs and nothing has had as nice tq/hp curves as the cam Dwayne spec'ed for and is in it. 270/276@50 .644/.624 on a 110LSA. I use a 1.6 rocker on int. and a 1.5 on ex.

Some measure the cam at 271 @ .050, mine measured 272 @ .050, that makes the math more simple.

But, for Strait up at a 106 ICL

--------open------ close-------
int: 30* BTDC, 62* ABDC
exh: 62* BBDC, 30* ATDC


But, as MP suggests a 104 ICL

-------open------ close-------
int: 32* BTDC, 60* ABDC
exh: 64* BBDC, 28* ATDC


But, Racers in the know, set it around a 100 ICL

-------open------ close-------
int: 36* BTDC, 56* ABDC
exh: 68* BBDC, 24* ATDC


See how Strait up works with symmetrical cams. With the Piston ATDC, the cams intake and exhaust lobes are centered as well between Max lift so the opening and closing numbers events match but on opposite sides of the pistons TDC

Ok. Ill see what i get with that. Thanks again.

One thing I could do that might make sense would be to get another 264/268 cam ground but on a different LSA. Maybe tighten it up to 106 and see what happens. That way most of the variables would be controlled. Not sure it would worth the time and effort to do that test, but it would be a logical thing to do.

Hughes engines grinds some of their cams on a 106. Not sure what they know about that. A narrower LSA would be interesting to see.