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396 Cam selection (i hate having to do this)

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bobj_70

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Discussion starter · #1 ·
I know you probably get tired of these threads, but i don't know what to get, and the machine shop wants to know.

I'm currently having a '68 396 w/ dome pistons, 454 open chamber heads, and an original crank for it, but i'll need a cam. lol

I want a slightly lopey idle, and lots of low end power because this is going into my street car. It will rarely see the strip.

What kind of cam should i get??

I've sent PM's to Harold, but no response. :confused:
 
#2 ·
We need a lot more info like for ex:


* what's intended use of car,street strip/all street/mostly strip?

* what rear gear and trans and if auto what stall if any?

* what carb and intake?

* what size dome on pistons, .182 or the larger one?

* what casting id are the heads and or what's the combuston chamber size?

* whats the budget for cam & lifters,$150-$200 for flat tappet cam or $600+ for roller setup?

* do you want to run hyd or solid cam?

Scott
 
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Discussion starter · #5 ·
SWHEATON said:
We need a lot more info like for ex:


* what's intended us of car/stre strip/all street/mostly strip?

* what rear gear and trans and if auto what stall if any?

* what carb and intake?

* what size dome on pistons, .182 or the larger one?

* what casting id are the heads and or what's the combuston chamber size?

* whats the budget for cam & lifters,$150-$200 for flat tappet cam or $600+ for roller setup?

* do you want to run hyd or solid cam?

And tats just for starters/lol!!!!
Click to expand...
It'll be MOSTLY street.
Rear will be taken care of later on, either 3.55 or 3.73.
I'll beef my TH350 if i can't get ahold of a TH400.
Carb wil probably be a Holley 750 or Demon, intake Edy RPM AG.
Converter will be decided on after cam selection.
What ever pistons came stock in a '68 396, all i know is they're domed.
Heads are 14092360, open chamber, will add 1.7 RR's, better springs.
No more than $300 for a flat tappet cam w/ lifters.

Low end power is a must!
 
#6 ·
Discussion starter · #8 ·
novadude said:
Won't CR be LOW with stock 325/350hp dome pistons and 454 Open Chamber heads? IF so, I'd go smaller than the cam recommended above. A small 396ci w/ low CR will probably not like a big cam. JMO.
Click to expand...
Then suggest something that can help me? :confused:

Lopey with lots of low end power.
 
#9 ·
Brandon, Novadude is correct in that you really need to figure our what your compression will be prior to selecting a cam. You need to determine the following items to determine your compression ratio:

Bore, Stroke, Head gasket thickness, deck height, piston volume (cc's), combustion chamber volume (cc's).

Here is a link that will help you calculate your CR.

http://www.rbracing-rsr.com/compstaticcalc.html

BTW what local machine shop did you end up choosing? They should be able to calculate all of this for you.
 
#11 ·
Lawson72 said:
comp 292 cam...put one in a 454 and 402 street motors...can't say nothing bad...
Click to expand...
Not really a good recommendation for a low compression 396 street motor where he is wanting to boost low speed torque. :rolleyes:
 
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Discussion starter · #12 ·
68chvlss396 said:
Brandon, Novadude is correct in that you really need to figure our what your compression will be prior to selecting a cam. You need to determine the following items to determine your compression ratio:

Bore, Stroke, Head gasket thickness, deck height, piston volume (cc's), combustion chamber volume (cc's).

Here is a link that will help you calculate your CR.

http://www.rbracing-rsr.com/compstaticcalc.html

BTW what local machine shop did you end up choosing? They should be able to calculate all of this for you.
Click to expand...
JB's
 
#13 ·
On a 396 with 10:1 compression increaseing the chamber 10cc drops the compression a little less than a point. I am not sure what the difference in chamber size from a stock 68 396 piston and the open chamber head he is using. But if the 68 piston gives 10:1 with a 107ish piston and the open chamber head is 119 then we are probably looking at high 8s to low 9s on compression.
 
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#14 ·
68chevelle533 said:
On a 396 with 10:1 compression increaseing the chamber 10cc drops the compression a little less than a point. I am not sure what the difference in chamber size from a stock 68 396 piston and the open chamber head he is using. But if the 68 piston gives 10:1 with a 107ish piston and the open chamber head is 119 then we are probably looking at high 8s to low 9s on compression.
Click to expand...
agree'd probably somewhere in the 8.8-9.1 range. I think this plus the Peanut Ports would probably be more suited for a cam in the high 210* or low 220* at .050. The low compression is going top help with the lope he wants I would run either of these cams, the second one being a little bigger

http://www.summitracing.com/parts/SUM-1301/

This cam is similiar to the one I had in My 396 sounded real good for a mostly stock motor

http://www.summitracing.com/parts/SUM-1796/
 
#16 ·
Discussion starter · #17 ·
GRN69CHV said:
http://www.summitracing.com/parts/ISK-396286/

http://www.summitracing.com/parts/SUM-1796/

http://www.summitracing.com/parts/LUN-07201/

All 108 LSA, single pattern cams. Install at 104ICL (typical 4* advanced). All will have a good lope at idle and produce a lot of torque early.

As for the trans, keep the T350. Freshen it up, good shift kit and use. Don't even consider a T400. T350 has lower gear ratios and consumes less power, perfect for a 396.
Click to expand...
Thanks for the trans info, now how would these cams work with these open chamber heads? I was talking to a guy at the machine shop and he mentioned my compression possibly dropping from 10:1, 10.5:1 down to low 9's.
 
#18 ·
Brandon,
WE already answered your last question....
modest duration, short Lobe sep, as much lift as you can throw in

PS, ditch the 2.56 gears ASAP.
 
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Discussion starter · #19 ·
kettbo said:
Brandon,
WE already answered your last question....
modest duration, short Lobe sep, as much lift as you can throw in

PS, ditch the 2.56 gears ASAP.
Click to expand...
working on that
 
Discussion starter · #20 ·
ok so i know now what to look for, but what brand??

Summit, Lunati, or Comp??

You guys have linked me to all of them lol which is best
 
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bobj_70
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