455 cam / build ideas

[Houndogforever]

So as I tear apart the old engine, I am starting to make some plans, and looking for some deals. I found out my existing heads have the 2.125 valves in them so I am having them mag checked and will get those freshened up this month. Just a little bowl smoothing and a fresh grind and seals.
This engine is going into a 67 2door skylark, which has a 2:78 posi rear and will have a TH400 trans. Suspension has all been done, brakes are all new. This is going to be a summer cruiser car, no track time except maybe a time or two just to see what it does. I don't expect times to be great because of the rear ratio, but maybe some day down the line I can swap in a different rear to make it quicker.

I have full length headers which I will probably try out, unless they give me too much trouble on ground clearance but that is far into the future. I have a new Performer manifold sitting on the shelf for the future too so I will use a quadrajet carb. Probably go to a breakerless distributor in the future for ease of maintenance but that isn't a big deal either way. It currently has a large cap dist. in it.

I do like a nice sound and a bit of a lope in the idol and am not worried about fuel efficiency since it is a weekender car. With that rear ratio, I will need the power to come on in the low end of RPM rather than higher.

So looking for recommendations about cam choice.
Depending on how the rockers and shafts look, if I need to replace them, is there a particular style that is better or worse?

The engine probably won't go together for a year, but if I can stumble onto a nice cam or valve train package online I could jump on it so long as it isn't something that just won't work.
Here is an example of a cam kit on ebay for a decent price, maybe.
http://www.ebay.com/itm/Cam-kit-for-...#ht_500wt_1413


This engine will not likely see over 5500rpm.


Thanks for any ideas.
Jon

[462 Chevelle]

With your gear and heads I would use a cam with some intake exh split rather than a straight pattern cam like the Ta-212

[RG67BEAST]

A split pattern is a better choice as stated. The cam/torque converter/rearend ratio should work as a combination. You should also take into account the static comp. ratio and whether or not you will use headers as to where to install the cam. With ex. manifolds you may want to advance the cam a bit more than the usual recommended 4* depending on cam choice.
A dual plane intake should be used with the 2.78 rear and a properly tuned q-jet. From the info so far the 212 cam is a good candidate or something similar. If you go too big it will be a dog off the line.
Ray

[NickEv]

I agree with the split cam although i believe you need up to 14-16 more degrees exhuast duration
It will allow you to run a smaller intake lobe to keep bottom end,yet with the longer exhaust lobe it will extend peak power out father
Good luck

[pmuller9]

Jon

What will the compression ratio be?

Paul

[Houndogforever]

Jon

What will the compression ratio be?

Paul

No particular plans at this point. Once I hear back from the shop on the heads, I will know what their size is and can better judge from there. Nothing high, I want to just run it on pump gas. I assume it would be somewhere in the 9.5 or 10 to 1, but that is just a guess based on the pulling it out of my a....

What would be a good goal to shoot for?

[pmuller9]

No particular plans at this point. Once I hear back from the shop on the heads, I will know what their size is and can better judge from there. Nothing high, I want to just run it on pump gas. I assume it would be somewhere in the 9.5 or 10 to 1, but that is just a guess based on the pulling it out of my a....

What would be a good goal to shoot for?

If you are looking at using a low to midrange cam like the TA-212, you want to restrict the compression ratio
to 9.5:1 for pump gas.
That will keep the Dynamic compression ratio under 8:1

Paul

[pmuller9]

Jon

I missed the part about you not caring about gas mileage. That makes a whole different story

That being the case, it simply becomes a matter of matching the torque converter to the power band no matter what the rear end ratio is.
As long as when you step on it from a low speed and the converter allows the engine to reach the start of the torque curve, it will pull the car instead of bogging.

Now you can have 10:1 compression and use a more aggressive cam.
As mentioned in the previous posts, you want a cam with a split profile where the exhaust duration is a lot more than the intake.

It would also be better if the lobe separation was 112 degrees or less. This gives you a more aggressive transition from low rpm to midrange
with better low end response.

Since fuel economy is not a consideration, you may want to idle around with slightly rough idle for that hot rod sound.
There you are looking at .050" overlap around 6 to 10 degrees.

The TA 290-94H should work nicely.
It has more exhaust duration and more exhaust valve lift over the intake to help extend the power band.
It also has a fair amount of lift overall which also helps widen the power band.

In addition the overlap will take advantage of the long tube headers (If you decide to use them).
The scavaging effect from the headers draws the intake charge into the chamber sooner at higher rpm which effectively increases the intake duration.

Paul

[Houndogforever]

I'm leaning to the ta_212 cam. This cam gives me the split duration that folks seem to say I need, plus will work well with my tall gears, plus I can run lower compression and not need to worry too much about detonation.
I haven't looked to much at my rocker shafts or rockers yet, still too dirty, to see if they are good or bad.

If I need to replace a bunch of the rockers, what advantage / disadvantage do I get if I step up to the 1.60 ratio rockers? I can see I get some more lift obviously, but does that give me more torque or more low end or high end or????

Will it change the power range higher or lower?

Thanks for all replies.

Jon

[pmuller9]

If I need to replace a bunch of the rockers, what advantage / disadvantage do I get if I step up to the 1.60 ratio rockers? I can see I get some more lift obviously, but does that give me more torque or more low end or high end or????

Will it change the power range higher or lower?

Thanks for all replies.

Jon

Jon

The increase in lift will give more torque over the entire power band.
As a result the power band is extended some at the high end.

Paul