camshaft and compression ratio

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red_duster74

red_duster74

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im rebuilding my /6 and i need some advice on what kind of camshaft i would need and what is a good compression ratio. im putting a holley 390 carb on it
 
Whats the application? WWhat are you trying to do with the car? I dont know much about cams but I've been told that 9 to 1 is the magic number for slants.
 
I don't have experience with slants but I'm building one. I've done tons of other engines through the years though. The biggest thing that seems to be the concensus with slants is not to overcam them. You left out literally every variable of information possible, so I don't know how in the world you can expect any accuarte answers here.
 
StrokerScamp is 'right-on'
If you believe engine simulation programs like desk top dyno,, I can show that for improved torque and Hp up to 4000 rpm, changing cams is the last thing you do,, start with improved carburation and exhaust, raise compression, optimize timing, head porting and OS valves, then change the cam...
most folks do the above and change the cam at the same time, because they are already into the motor. Its the "package" that makes the difference,, and the package is determined by your goals and available $
 
well this is just going to be a street car and my main goal is to rebuild the motor and make it run a lot better than it is now and maybe get my hp up to 220
 
220 will be a really hot slant.
 
A turbo or blower kit would probably be the best to get that horsepower and still be streetable. Use the cam they recommend.
 
cudamark said:
A turbo or blower kit would probably be the best to get that horsepower and still be streetable. Use the cam they recommend.
Click to expand...

I agree. I am thinkin about that one myself.
 
for a slant street car,, play to what the slant already has,,,low end torque.

there are engine mods that you can do that will give a 50% increase in torque at 4K rpm,, could easily hit 175 hp at 5000 rpm,, and are do able for a person getting started, and will provide a nice foundation in experience, would be a hot yet drive-able street slant.
2 bbl or a 4 bbl carb
improved exhaust
valves, porting
ignition

there are a number of cams that could go well in that mix,, google erson rv-10 or rv-15 for a start.
 
lots of turbo cars are carb fueled, some blow through, some pull through.
I'm just saying for a first project,, a turbo slant woud not be an EZ start.
Not saying it could not be done, go for it if you want it,, or say you want it, but are willing to build a foundation, so that when you get it, its done right,, and that's what I'm talking about
 
This for me is a new area too. I've decided to replace the previously installed enemic and sick 170 in my '65 with a 225. So I've been looking around. I do a decent amount of V8 work and the idea of getting more air and fuel in is pretty universal. But, a V8 has an intake event every 90° of crank rotation, the 6cyl only has an intake event every 120°. So it's easy to "overcam" them. So I'd keep things conservative, especially if you have power brakes and high (numerically low) rear gearing. If you are not going to add compression which I do think is extremely important, I wouldnt add a cam that's too much larger than 217°@ .050. Unfortunately, the cam choices as compared to a V8 are fairly dismal...lol. I'm not anywhere near the "building" phase but I think I'm going to get a custom cam for mine.
 
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