LD85

OK, I have 406CI with 233/233 cam that dont seem to take full advantage of the AFR210 heads. I have a Holley Stealth Ram intake (see sig) that I am using.

I want to stay with a HR cam and I do not want to go higher than .590-.600 lift.

AFR recommends a 242/246 cam to "really make the heads shine"

Engine specs;
406-CI
Bullet Billet Custom Grind HR cam 233/233, 284/289, .576 lift w/1.6rr's
11:1 CR
68 CC, AFR 210 heads hand ported and valves backcut
Head flow is 297 CFM @ .600 lift
Wiseco Forged Pistons, Eagle Forged Rods & 4340/Crank.
3.75 crank stroke / 5.7 rods
Centerforce 400 Crank Flywheel / Centerforce DF II Clutch
Flow Kooler Water pump w/ Dewitts Radiator / dual fan
ZF 6 speed , Hurst Billet Shifter
3.45 rear gear
Hooker 2151 cut and rewelded to clear plugs
BBK 58 mm TB
FMS 24 # injectors
MSD 8366 Small Cap, MSD 6AL, MSD 8.5mm wires
Accell Shorty Plugs
86-89,,, 165/ECM
Holley Stealth Ram

http://forums.corvetteforum.com/show...post1556252448

Deakins

Where do you want the power and how high of RPM do you want to turn it?

LD85

Well, the dyno currently peaks at 5850 and stays the same (385rwhp) up to 6300

I would like to keep the peak below 6500

LD85

Looking at this
http://www.compcams.com/Technical/Dy...4HR-10_001.asp

Deakins

On the 400's I have raced I always found that cams were really tamed down when compared to the 350's. The cam you listed has pretty good duration@50 but with the 110 ls I would push it a little higher. Something like 250 would be preferred to get it up to 6500 strong. Also, if idle quality is not a prime concern you could look into a 106 ls cam. These are used mostly in circle track for the very broad tq curve and is mostly what we put in our engines destined for the street in hot rods. It sacrifices some idle quality but gains yields an engine that starts pulling and seems to never stop! With that said the cam you linked us to will wake it up; but in this large of an engine I would push it a little further. I have to run out tonight but I will see if I can dig up the specs on the 406 that we ran on the street a few years ago for comparison.

gkull

My original 427 SBC build used the CC 242/246 hr 110 with AFR 210 heads flat milled to 64 cc. I used solid rollers on it.

It would be the max cam I would use with HR 6500 rpm limitations.

It had a really strong mid range charge

msb184

Years ago when most engine builds used some type of stock head I relied on the Cam grinders advice to choose a cam. They developed their profiles on stock or ported stock heads. Now, I almost never use stock heads on anything. Your engine will run best with AFR's profile. They have no doubt spent many hours to come up with the best combination for those heads. Two heads from different suppliers could have very different flow specs. It's not possible for a cam grinder to come up with profiles for every aftermarket head, TOO many heads to plan for. I use ET heads on LS,BB & SB engines now. I tell them what the motor is used for & they suggest the best head & cam profile to go with them. So far they have produced some incredible results. Blower motors are way less picky about the cam. Wide LSA helps,but otherwise a fairly mild cam will get it done.

LD85

Thanks for the replys, I may go with a custom grind to get a 112LS.

Gonna call Bob at Bullet and see what he says.

ralph

Larry, i've got a 246/246 solid roller in my 406 on a 112LSA with similar heads. That cam is probably pretty close to a 238/238 hyd roller. If you plan to use the car on the street, i wouldn't go much bigger. I've got about 13 inches of vacuum at a 950 rpm idle. The power brakes work but get pretty stiff in stop & go traffic and you can really feel the difference on the pedal when you rev the engine. The idle quality isn't too bad, but i had to trick the stock 85 ECM to limit the BLMs at idle or it would run super rich. The overlap in the cam dilutes the exhaust with fresh air, confusing the O2 sensor. My peak is probably at around 6000 rpms. It takes a lot of air and cam to get a big sb to peak at 6500. Are you sure that is what you want? Your heads seem adequate, but is everything else? Any restriction in the intake or exhaust can limit your peak. Plus i wouldn't expect to use much more of the rpm range if you plan to stay with a hyd roller. A 250+ duration hyd roller is a very big cam and while a tight lsa might make good power, you'll probably need an aftermarket ECM to tune it, a pretty high CR to make it work and manual brakes to stop it.

BTW, my EA Pro simulator likes a solid cam of about 235 deg much better than my current cam up until almost 6000 rpms. One of these days i've got to try it.

LD85

Very good points Ralph! I plan on keeping the cam and putting a McLeod street twin in the car this month with a new 4340 Forged Crank.

My car has never "not had" a clutch slippage issue and I can't say for sure that my issues are not clutch related.

I agree that the Hyd-Rollers are the next restriction and I dont plan on ever going to a Solid Roller,,,hence, 6000-6300rpm is the max

BTW, I did speak with Bullet Cams and they will make me a 238/244 Hyd Roller with a 112-LS for $310,, just a fun fact They dont want to go any higher and it makes sense.

Lastly with the new clutch and a fresh engine, I will get some dyno results before I do any new mods.

I should be on the dyno before the middle of June.

ralph

Good luck Larry. Sounds like the guy at bullet has it right.