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MILD cam for 396

17K views 12 replies 7 participants last post by  monzter 
#1 ·
Hey guys i just bought a smooth, running 402/396 big block chevy motor that was in a chevy truck. The engine ran good but I plan on putting it into a 71 nova. Now here is where i need your guys help. I plan on resealing the engine except for the headgaskets due to it being a leaker. I want to run a stock converter in a th350 and 3.08 gears in a ten bolt. I am running headers and will change to a performer intake and 750 carb. Now i need suggestions for a mild cam that will work well with these mild parts. I want low to mid range hp and torque. I dont care if there is a choppy idle or not. I also would like to run stock valve springs if possible. Some guys swear by those summit camshafts. Maybe a vodoo 60202? Oh and this is a stock 396/402 so it will have the low compression head n piston combo. Thanx guys.
 
#4 · (Edited)
The smallest BBC summit racing brand cam will do the trick. I have run stock springs with it and it works ok. Specs are 276/280 advertised, 208/218 at 0.050", 112 lsa, and 0.475"/0.500" lift. Makes power to around 5000 rpms and has a smooth idle. ($100 with lifters)

http://www.summitracing.com/parts/sum-k1300/overview/make/chevrolet

Upgrade to long slot rockers. Also summit racing ($65)

Always a good idea to check valve stack height. You can do it will the heads on. Use a valve spring compressor that attaches to the rocker arm stud and a caliper. Check a few intakes and a few exhaust valves.

If the springs can handle 0.050" more than the cam then run it. If you find the valves float at higher rpms, then install stronger springs later. Also not a bad idea to break-in the new cam with the stock (weaker) springs.

I recommend a holley 750 3310 carb and a dual plane intake with a square flange. Avoid carter and edelbrock carbs, as they tend to vapor lock and developed sticky accelerator pumps.

396 truck intakes are nice and work well with a q-jet. If you have the high rise truck intake with a good running q-jet then run that.

Also a good idea to use an HEI ignition and around 40 degrees total mechanical ignition timing. And get an adjustable vacuum advance and set it to 10 degrees and use a manifold vacuum source.
 
#9 ·
If you get a cam like the extreme or voodoo or most any other aftermarket manufacture then you will need to change the valve springs.

The summit cam has soft ramps and relatively low lift which makes it easier for the springs to control the valves. Any more cam then this, and it will require a spring change.

Even with new springs, I would not use an extreme or voodoo cam as these cams have very aggressive lift rates and are very hard on lifter and cam lobes. So, these cam have a much higher failure rate, especially with todays low emissions oils (low on anti wear additives once needed to flat tappet cams).

Finally hard to beat the summit racing $98 cam and lifter set. Sure, power is a little less compared to the extreme cam due to the slower lobe ramps and lower lift, but the cam will last a long time. And it is a big improvement over stock.
 
#10 ·
Hey guys. Cant believe its been 2 years already. So I ended up going with the summit cam and it ran great! Im back on here because I would like to upgrade some parts in the nova for this upcoming drag race season. Ok my question is can I put a set of closed chamber 215 heads on this 402 with no problems? I keep getting different responses. Some guys say it will clear the factory domes others say I need "closed chamber" dome pistons to clear as I have the factory 292 heads and factory dome pistons. Id like to run these to up the compression so I can run a better cam with a stall converter and 3.73 gears for some fun at the track. Thanks again guys!
 
#11 ·
The dome on a factory cast type 402 piston will clear a closed chamber head, but if it is a factory 11-1 forged piston. There can be some minor interferance on the exhaust dome, valve relief, outer edge. Just touches on some heads/thin steel shim gasket. :thumbup: Will cause a funny/strange little knock noise at higher revs... Ask me how I know
 
#12 ·
Thanks Bob! These are factory domes and im almost positive these are not 11-1 pistons lol. This was a truly factory engine as it still had the plastic ring gear on the camshaft gear and was running a stock intake manifold and quadrajet. Even the head date codes matched. And in no way did it sound like it had that much compression lol. I just wanted to freshen this engine up with an intake cam and carb as well as some more compression without changing pistons. Thanks again
 
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