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Need help!- Low comp 440 cam choice.

Reamzer

Reamzer

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I have a 1967 coronet with a 440 out of a 77 motor home. It has factory pistons and 452 heads, the comp is low low low.. I installed the 509/292 hydraulic comp cam and it seems to be to large for the low comp motor and is causing all sorts of problems.. I was wondering what the best performance street/strip cam choice would be?
 
What you really need is the least amount of lobe overlap you can get + as much lift/duration as you can get with that small lobe overlap (that doesn't hit the pistons).... basically, a high-lift RV cam..... a custom grind might be a good idea in this particular case.
 
64SF said:
Agree ...check out their Whiplash cam.
Click to expand...

I looked into that cam, I was told it doesnt provide enough vacuum for the brakes?

Love the sound of it, people seem to love it from what i read...just cant get a clear answer on the vac
 
I've run an old purple 509 cam up until last Fall before I pulled it out. It wasn't giving me nearly enough vacuum to run my brakes (4"-6" at idle). It also has a high lobe overlap (for a street cam) which bleeds off compression (both intake & exhaust valves are open at the same time for a long while - lobes "overlap") and you don't have much compression to start with.
 
People told me the 284/484 was "too much cam" for my 1970 9.5:1 383.

It did just fine installed properly degreed.

At 8.2 you may need one or two "steps" smaller.
 
Stegs said:
I looked into that cam, I was told it doesnt provide enough vacuum for the brakes?

Love the sound of it, people seem to love it from what i read...just cant get a clear answer on the vac
Click to expand...

Call Hughes...they are very helpful. I just bought my second cam from them for the 451 I'm building.
 
64SF said:
Call Hughes...they are very helpful. I just bought my second cam from them for the 451 I'm building.
Click to expand...

I called on the whiplash cam for a low compression 440. Thats what that cam was designed for. I asked about vac for the brakes. Their response was along the lines of "some people run this cam just fine, others add a canister...it really depends on the car"

I like the idea of this cam, it sounds great and really performs from what i read...i just dont know anything about a vac canister....seems like another thing to go bad/leak
 
There may be better cams for your application but FWIW several years ago I had a 1977 400 that I installed a MP 383/440 factory grind cam in and it seemed to be a good choice.
 
PurpleBeeper said:
I've run an old purple 509 cam up until last Fall before I pulled it out. It wasn't giving me nearly enough vacuum to run my brakes (4"-6" at idle). It also has a high lobe overlap (for a street cam) which bleeds off compression (both intake & exhaust valves are open at the same time for a long while - lobes "overlap") and you don't have much compression to start with.
Click to expand...
I thought about it, but no, I'm not going to let this pass. Your lack of vacuum is because of the overlap with the intake valve opening while the exhaust is closing. But the poor dynamic compression is caused by the late closing of the intake valve and nothing to do with valve overlap, as that happens while the intake is opening. That is why when using the 509 cam on a lower compression engine you use a lot of cam advance so the intake closes sooner and builds compression earlier.
 
I generally advance cams and more so if they are going into a low compression engine. It just depends on the opening and closing stats. And the real dyno is at the track. Helped a guy with a heavy car advance his 590 cam while AT the track and it picked up a tenth. That ain't no small beans. Power brakes on a hot rod?? Really? Never had that problem before :)
 
I used a comp camXE268H in a low compression 440 worked well. I used a whiplash in a low compression 400. It made ok power but idle quality sucked and didn't make enough vacuum for power brakes.
 
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