The Grumpy Grease Monkey mechanical engineer.
I just sent you an email regarding getting a cam recommendation for my 406 build. Not sure if it'll come through or not as gmail may not recognize my comcast.net email as legit.
So I'll repeat myself here, I was just wondering if I could give you all the pertinents regarding my build and you'd be able to give me a cam recommendation?
list as much info about the car, drive train tires gearing and all the engine components, heads, intake, compression,headers exhaust system, ignition, rotating assembly ETC. what do you intend to do with the car?
what work can you do vs need to farm out to have done?and Ill ask questions if I need more details, to figure out what you need
many guys ignore proven combos, because it may cost more than they want to spend, and either insist on using components they own currently or think they can buy far less expensively than the components, I know from experience will actually work.
This is a v2.0 of the 406 I built as my first build back in 1997. It originally had a 750 Holley, Holley Contender intake, 461 double-humps, 9.4 CR, and a pretty tame Comp 268XE flat tappet. But she was fairly strong for being so simple and the car being so heavy.
For v2.0, the goal is 12.5s (ideally lower 12s after a year or more of tuning and parts upgrades) and very reliable road manners so I can drive 2-3-4 hours at a time to out-of-state car shows or events without worry.
Here's the details:
- 68 Biscayne
- Right at 4,000 with me in it
- 75% Street/25% Strip (Read: pretty aggressive street car to most. Though probably not that aggressive in your world)
- 406 SBC (stock block)
- 750 Holley (but will likely need to move to an 850 or even a "mild" 950HP down the road if budget allows)
- Holley Contender dual plane intake (mildly ported and port-matched to heads)
- Dart Iron Eagle Platinum 200cc heads with "medium" port job (I've opened the intake runners at the "pushrod pinch", but probably won't work the bowls, cleaned up the combustion chambers and smoothed the exhaust runners.)
- 1.6 intake and 1.5 exhaust roller rockers
- 10.5 CR
- 6" Scat rods (thus requiring reduced base circle cam, which I didn't know till after I got the internally-balanced Scat rotating assy.)
- 1 5/8" Hedman headers/2.5" Pypes mandrel-bent exhaust with their RacePro (least restrictive) mufflers. I realize I'm a bit small on the headers, but 1 3/4" or even 1 7/8" just really aren't in the cards at this time. The heads are square-port and the headers are round, so I'll be welding up the headers and grinding them out so there's no step.
- TH200-4R/3200 stall/3.42 12 bolt (will probably bump up to a 3.73 after the engine's in and running)
I'd like to run it out to somewhere around 6200-6400 if possible.
I'm going to do a hydraulic (retro-fit) roller.
I will be running an old-fashioned clutch fan as I don't have the electrical system (still 1968-fresh) to handle electric fans. And I'll be starting her up on a stock HEI dizzy. But I plan to upgrade to a DUI HEI in the months after the engine's running.
I probably missed something, so just let me know if you need any other details. I look forward to your input.
if your putting the emphasis, on peak hp rather than street-ability the cams below will work ok, with your 200 cc port heads and 3200 rpm stall converter, but will work best if matched to the correct drive train gearing, and a 3.42:1 is marginal
or a bit milder, and a better match to the 3.42:1 rear gear
(why not check with both crane and CROWER for their ideas?)
a rocker stud girdle for increased valve train rigidity,might help,and while a 3.73:1 would help, a 3.90:1-4.11:1 rear gear would help more, the 3.42:1 will not be ideal with this cam, and I would not be overly concerned with the 750 cfm carb restricting power, Id be far more concerned with a restrictive exhaust system past the headers, and getting the tuning right
http://garage.grumpysperformance.co...y-in-building-a-good-engine.11682/#post-54682I've heard of both Crane and Crower many times, but for some reason, just hadn't considered them. I think my impression of Crane is that they're past their prime or they're basically just Comp with the Crane label. But my impression of Crower is that they're still a high-quality, very revered brand more suited to race cars than street cars. I guess I can give them both a call and see what they'd recommend.
So both of these are off-the-shelf cams which is interesting. I see Crane's is a reduced-base circle, but can't find whether or not Crower's is.
Minimum operating rpm is interesting. (None of the other guys gave me that figure and I never thought to ask.) I was hoping with my overdrive and lock-up converter to be loping down the highway at 70mph at around 2200-2400. But their specs say 2800. Yikes. Guess I can't have everything - well, with a carbureted GEN 1 SBC combo anyway.
The stud girdle was mentioned. I'll be running 7/16" screw-in studs which will help a bit. But yes, a girdle may be another part that comes along after she's up and running and I can filter some funds back into my "fun budget".
I think the headers need to be a bit bigger myself. The exhaust could stand to be 3", but b/c it's mandrel-bent and the muffs are a straight-thru design, I'm okay with that compromise. I may ditch the tailpipes and run turn-downs. But that's all the more I'm willing to do on the exhaust. It's not as restrictive as most guy's 2 1/2" kink-bent, poorly run exhaust systems.
Thanks for digging into this Grumpy! Gave me some more food for thought.