What Cam

[MoparCain]

I have a 68 440 bored 40 with 10.1 flat tops. Running 516 closed chamber heads bone stock was wondering what cam to use. I want to stay with a hydralic cam, and will be running 3.91 gears in a 66 belvedere two with an automatic and a 3000 stall. Car will be a street/strip. Also it has manual steering and brakes. How radical of a cam can I get away with. Running 1/75 headers and no intake yet.
Also if you can recommend a good carb that would help also.

 

[MikeyT]

I would look at a few of the comp cams. I really like both the comp cam XE268, and comp cam XE274. I liked both of them, and felt decent performwnce for street strip car.

Mike

 

[747mopar]

The heads will be a factor, a bigger cam then they will flow won't do you much good. I went with comp cams 21-224-4 but I'm running 3.55's and built mine more towards street use. I have 452 heads that I mildly ported and put the larger valves in, they were flowed and are good for 6,500+ rpm. I don't know how your heads flow but if they fail to keep gaining cfm before your cam reaches it's peak rpm (1,500-6,500 for example) then your heads become the limiting factor. If your wanting that rough choppy idle but would like good streetability check out comp cams Thumper series cams, I've seen dyno test "they make some good power". As far as carb goes, that will depend on your rpm range, 750-850 cfm likely. I like the holley's and demon's, for heavier cars they reccomend vac. sec. do to the fact that a heavy car won't accelurate fast enough to use the extra fuel being dumped in although I'm sure you could make one work. Summit racing has a cfm calculator on they're website, enter your cubes and max rpm. Good luck

 

[RustyRatRod]

Yup, the 516s do have smaller ports, but they can be blown out and ported to flow 600 HP if that's what you want. It just takes money. I think the Comps mentioned above are really small for a street strip 440 with 3.91 gears, but that's just my opinion. I would lean more toward something like the MP 557 or even the 590, especially if your compression is a blueprinted 10:1 or greater. You'll need to bleed off some cylinder pressure for pump gas. You're also going to need valve notches to go with any sort of a cam that's not totally useless.

 

[MoparCain]

Thanks for the responses, I am going to try the 516's like they are and see how they work.

 

[68 HEMI GTS]

any kind of cam at all and your going to want to check retainer to guide clearance. if your running stock rockers your limited to around 0.500 lift. a couple things to keep in mind. lots of cams out there to choose from, also hard to go wrong with the old faithful MP sticks. .484 cams work pretty well with automatics. all depends on how much you want to get into

 

[Meep-Meep]

Your build sounds like my 66 440 Belvedere. I have a tiny cam and it runs great - even with a factory iron intake. Personally I'd run about a 110-112 lobe separation and slightly more duration than a magnum cam. A lot of lift won't do you much good plus that's not the end all be all in cam selection. I'm running the MoPar .455" / 270 on a 112 and it's great with 3.55 gears.

 

[67 B-body]

I built a 383 for my friends 67 notch back Cuda. I used the MP 484 cam in that engine with stock heads, flat top pistons. It ran very well!!! I never thought I would see that old 383 "it was originally from my 69 RR" perform that well....
I know your's is a 440,,, but with factory cast iron heads, and street / strip, I think the cam would work just as well in your application.

 

[national]

Remember a stock RR cam is 268 duration..more like 114 centerline..Id go with a 284 or bigger..with a 3k converter & 3.91 gears you can get away with more cam..I think comp has a 284 or 288 XE cam or go to hughes site..they have several good cams..