i am working on building a new engine for my 90 vette M6. i have a 404 CID forged bottom end with 13:1 compression with -11 Brodix 227cc heads. i plan on switching to E85 fuel for the compression.
I will probably end up running a single plane EFI intake.

I am looking for 500+ HP at the crank.

I contacted Comp and Crower about cam recommendations and here is what they cam back with.

Comp: 0.620ish lift with 245ish duration @ 0.050 with a 110 LSA (recommended a custom grind)
Crower: 0.626/0.652 lift with 254/262 @0.50 duration on a 114 LSA

my qustion is why is Crower recomending a 114 LSA. i like this idea because i think it will work better with the EFI but what will this do to the power band?

I am looking for cam ideas for guys who have build high HP engines on EFI.

 

LCA is only one part of the cam choice you need to look at overlap and valve closing points to determine how the cams will act. The larger cam with more duration and 114 LCA will actually be harder to tune. That being said either cam can be tuned by a good tuner. The smaller cam will make more low end power and come on sooner. That being said what are your rpm goals? I believe either cam will make 500 hp at the crank without a problem. Probably closer to 600 hp if the heads are good.

 

I have a mini-ram 427 sb with a crower solid roller with a 112 lsa.My motor is only 11:1 CR,with your 13:1 i think crower is seeing all that CR, with tight lsa it will increase cyl pressure .You have one of the best heads you can get.I agree with the above post,600 hp is not out of reach.Good luck

 

I am looking for a street car so I'm thinking power between 2500 to 6500 or so. The engine can handle about anything I can throw at it. It was built as a sprint car engine originally.
So If I go with the 114 LSA that will help lower dynamic compression and help top end? Which is good.
Only question is how bad will it hurt bottom end preformance? Or with the bigger cubes and high compression will I not loose that much?

 

I would think your gearing will come into play on a street car.Mike Jones @jonescams.com gave me alot of info on cams,that's what i'm looking into myself.Your target RPM range may lead me to the smaller cam.So many thing come into play like, trans,gears,weight of car, etc..you can e-mail jones cams for a recommendation.Keep us posted,sounds like a killer build.

 

The Comp Cam is a straight up turd. No point in running a Mech roller that small. All the disadvantages of a Mech roller with none of the advantages.... I'd just run a hyd roller in it of I was going to use something that small...

Infact the hyd roller in my daily driver 92 6spd is that size and it's only 380 inches with a converted Single Plane Intake. Makes 487 RWHP 410 RWTQ and has been 11.0's at 128 MPH in the 1/4 on street tires - in an other wise stock 1992 Corvette.

The Crower lobes could be decent (8 degres of split is correct IMO for those cyl heads) but it's totally on the wrong Lobe Centers for a N/A engine with a single plane intake.

I can tell you in any N/A engine - That cam ground straight up on 114 wouldn't pull a greasy string out of a sick cats ***.

LSA won't effect DCR. The Intake Centerline and Intake Advertised Duration affect DCR.... specifically - the Intake Valve Closing Point. The earlier you close the Intake Valve - the more DCR you have.

I personally would look for camshaft around.

300/308 @ .020
252/260 @ .050
.622/.622 (1.5 rocker)
108 ICL
112 LSA

My recomendation is from Mike Jones' lobe profiles. I'd be glad to give you the lobe profile ID numbers if your interested in having him grind you one.
Will

 

yes i agree gearing and the rest of the car all comes into play. i plan on gearing it correctly to but waiting to figure out the motor before i decide.

Yea i think the 114 LSA seems kinda wide not sure why they recommended it unless they were thinking with the 13:1 compression i could get away with it.

I like your numbers on the 112 LSA. i am not overly worried about the power band i just do not want a total turd down low because it will be a street car.

YEa i will hit you up about a cam from Jones, i am not ready to buy anything yet waiting to sell my 383 i have now to get the money to finish the 404

i do worry about it being a little much for a "street" car. but hey you got to try it to find out lol.

 

I contacted Jones Cams and here is what they recomened.

Cam# SBCR/Cast, R74425-76412-110
248/254 @.050"
.425"/.412" Lobe Lift (.622/.612)
110 LSA

This is one of there "inverse Radius Rollers". this seems like a pretty large cam how do you guys feel this will affect lower end performance?

 

Thats not really big at all for your ci youll have plenty of low end just off ci alone. Have something 12 deg bigger in a 383

Jones would give a better recommendation than most here hes been at it a LONG time.

 

That is a fairly small cam for a mech roller.... It's 2 lobe profiless smaller than what I recomend.

The low end power will be very good.... proballly too good for street tires.

He's trying to give you instant 100% power application.... like a race car needs comming off a corner. The drive will notice that it's all there just as soon as you touch the throttle....

I was trying to spread the power out up in the RPM range a littler higher and kill a little low end response.... this makes it seem smother at WOT from low RPM to the driver.
Will

 

Yea I see what you mean. I think with this motor the sky is the limit as far as cams. The one thing I do not like about the cam he recommended is the large over lap (around 80 degress) but with the high compression maybe that's not a bad thing eaither.
Eaither way this thing is gonna be a little on the crazy side
That's part of what I like with your sujestion with the 112 I think the over lap will be a little less

 

The Overlap is actually 80 degrees on both his and my cam recomendations.

This should be a very important lesson to those that look at "LSA" as a magical number thats important to consider when selecting a camshaft.... It's NOT. It's just a number and it being 114 or 106 dosen't tell you anything important about random camshafts.

Overlap is an important event that does way more than make an engine lope or not at idle....

I did NOT even know the LSA was 112 on the cam I recomended for you until after I did the math on the lobe profiles and opening/closing events that I settled on. I did know how much overlap it had thou....

Just some things to think about.

Will

 

I dont see why you need to go solid roller here.

Up to 7000 rpm i would go morel lifters and good hyd roller profile, something in the low 240's duration intake, .600" with 1.6 or can do it with a 1.5. Tighter sep, 110-111.

I got a bigger head on my 400 and hyd roller 246/252 .640" and it turns 7200 fine with 25 lbs of boost behind it. Its on a 113.5 lsa for turbos but would run nice all motor. I'd just tighten it up a tiny bit