suggest an intake for a 496 BBC engine

grumpyvette

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I have a 10.5:1 496 with 315cc Full CNC heads from AFR. I plan on running it to 6800 or so with a .670/.670 lift SR cam with 262/272 duration in an all motor setup. I am looking for peoples opinions on here about the BEST intake manifold to run. I will port match the intake upon receipt and do a little blending in the plenum area. I am looking for suggestions like 2907 vs 2927 vs Sniper jr, etc. I plan on using a pro systems SV1, but I am open to suggestions. No nitrous, and no race gas used here. Pump gas setup in a 3000lb Street strip machine. Thank you for your input, I can assure you that it is greatly appreciated.

portw1.jpg

most intakes require gasket matching to maximize the flow potential
portw2.jpg

simply open the ports to match and transition too the heads and blend back any change in cross sectional area up the runners at least an inch or more
portw3.jpg

don,t forget the plenum and runner entrance needs smoothing


theres a super strong tendency to select the intake that can potentially make you the most peak hp, but thats not always the correct choice!
obviously you have rectangle port heads rather than the oval port head intake pictured above but much of the same info applies
yes its obvious with a solid roller cam like that the cars far from a daily driver designed to run to the local grocery or take long trips but
Id be more interested in finding out how much street driving vs actual strip time the engines likely to see before Id suggest eliminating the air gap rpm dual plane from consideration,I build mostly engines for the muscle car crowd,and a few strip engines, durability and instant responsiveness are the key in most of the builds, Id easily sacrifice 25 peak hp to add 50 ft lbs of torque at 3000rpm,on a car engine designed for street use, now theres zero doubt that a properly matched single plane can produce a bit more peak hp, but I build 489-496 engines fairly frequently for guys that drive the car once or twice a year at the strip and spend 98% of their time cruising or playing stop light to stop light , grand prix and you have to be realistic about what the cars actually going to be used for, peak hp is great, but if he REALLY spends 98% of his time on the street the RPM air gaps probably the better choice, if his cars used mostly doing burn-outs in the local burger joints parking lot and embarrassing ricers on the street.
huge duration cams and drooling over peak dyno numbers might be impressive but an engine built for peak hp is seldom fun to drive on the street as daily transportation and can be a P.I.T.A. in traffic on a 100 degree day
now obviously the components used has a huge effect on what you can get away with safely but ID limit it to 6400rpm-6500rpm if it was my engine, thats about 4500fpm and thats usually about the limit that a well built engine can tolerate on a long term basis , now if you really want to push things you can exceed that but stress is cumulative and big block rotating assembly's are heavy , and a dual plane intake on a 496 bbc engine with those heads and that cam won,t be giving up a great deal in average hp to the single plane intakes
Im in no way debating, that the single plane intake makes better peak or upper rpm horsepower, on a car like that, I have a GREAT deal of respect for the pro engine builders like
http://www.lewisracingengines.com/

http://www.ultrastreet.net/?gclid=CNuDr ... 7AodXHVqNQ

http://www.rehermorrison.com/default.htm

http://www.roushperformance.com/engines/


http://garage.grumpysperformance.com/index.php?threads/bbc-related-links-and-useful-info.17140/

ability's and the engines they build, yes, I fully agree with what they said as to upper rpm and peak hp/ what I'm simply saying is to realistically assess what the cars used for most of the time, and the whole ball games not dependent on PEAK HP.
anytime I have a guy say its going to be a STREET/STRIP combo , I want to know realistically how much street time, and in most cases I see the guy takes the car to the strip 2-3 times a year and makes 2-3 passes and spends the rest of the year smoking the tires in parking lots or doing two gear acceleration testing against some guy in the lane next to him and shutting it down at 60 mph, and wishing the cam he installed was not a P.I.T.A. to drive in traffic and wishing he got better mileage and could use the cheaper 87 octane fuel.
which hardly qualify s as a race engine in my view.
I'm simply saying lets define the cars actual expected use before selecting the correct intake for the application
I think we looking at things from a different perspective, you deal mostly with race engines and peak hp is impressive, and while I build far fewer engines, (3-6 a year most years) my concern is mostly for long term durability (ie making the engine last 60K-80K) and having no problems with parts breaking while still producing a fun to drive neck snapping combo for street use.
P12CHARTS.jpg


I guess we just have a different perspective, I try to design engine combos too maximize an engines durability and too maximize average useful torque curve over its expected lifespan and operating range and if that requires a trade-off that might cost a few peak hp, its a trade-off Im happy to make, you need to have a running dependable car, in my opinion far more than an impressive dyno sheet printed out in the glove compartment while your rebuilding what WAS a KILLER COMBO.
Ive built lots of 489-496-even a few 540 BBC engines and most of them are still running fine, and the only ones I,m aware of that are not, were significantly modified AFTER they left my shop, now don,t think those engines did not have respectable 575-660 hp, and yeah I could easily boost that by 50 plus hp, but for the people I generally build engines for its basically meaningless, few race seriously, most just want a "fast, responsive,dependable, muscle car" and if it runs low11- mid10 seconds they are thrilled
 
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