7-7500 rpm with a single holley 850?
Good question
496x7500(rpm)=3,720,000/3456=1,076(cfm)
1,076 x 1.1(ve of 110%) = 1,183 cfm required by a 496 at 7,500 rpm's.
Sleeper CP
Big Inch Ford Lover
7-7500 rpm with a single holley 850?
As much as I am the pain in the arse guy who seems to always think everyone with an 850 on a 454 jet-boat is overcarbing, An 850 on a 500" motor at 7-grand is a pretty drastic UNDER carb IMO.
I'm with brad & sleeper on this one.
496 bbc, 9.5:1 comp, oval port heads have'nt decided on a cam yet but it will be a big nasty flat tappet solid lifter from Clay Smith. I was curious what single plane intake works best? Single 4 barrel Holley 850cfm. I see the Victor is used alot but what about the Team G? Any others?I am no expert on chevys but are you using an oval port head like a 353049 or 990 head? I was told that a 454-468 is as big as you should go on a factory oval port head and that they would not make good power after 5500 RPM. Shoudn't a 496 have square port heads on a 7000 RPM motor. I am running 049 ported heads on my 454 with the performer RPM air gap intake. I really like the perforamance of the intake. Like I said I am no expert and have learned quite a bit off this site
If you really want this thing to run right, get the heads flowed. I think you'll find that you're going to be a little on the shy side of what you need for a 496 turning 7000+ (ported by a pro, you'll have a better chance, but still going to be shy) although with a good roller, you might get there. I don't think you'll do it with a flat tappet, though. With a single four, an 850, and that oval port Dart, you'll have some serious throttle response, that's for sure, but I'm thinking it'll be done by 6000, maybe a little more. Of course, if you want to spend a lot of $$ and get really trick with long rockers, custom grind, trick porting, big valves, mucho compression, light weight rotating assy, etc.....:idea:
Good question
496x7500(rpm)=3,720,000/3456=1,076(cfm)
1,076 x 1.1(ve of 110%) = 1,183 cfm required by a 496 at 7,500 rpm's.
Sleeper CP
Big Inch Ford LoverI don't think you'd never see 110% ve on this build.
Dart.
I wouldn't hesitate to use either of your choices, or the dart, except the issue of your oval port heads, and the availability of your manifold of choice to match them. I don't know if you could port match a rectangle intake to an oval port head.The mismatch isn't as big a deal as you'd think. Certainly not worth the effort to make a rect. port fit the oval. The air will pack against the exposed intake surface on the head (going into the port) and form it's own boundry layer, actually providing for a fairly smooth transition. More important would be the plenum volume and runner entry size and shape to feed the engine. I think (not sure, though) the Dart is a rect port intake that they reshaped the runners down stream, so it probably has all it needs in the plenum/entry area. The velocity on a 496 at 7500 with this inatke on stock ovals (at the choke) is probably very high. Even though this is an oval port intake, I'm pretty sure it was designed to work with Dart's oval port Merlins or something similar, which flow better than 990's.
I don't think you'd never see 110% ve on this build.
9.5:1 and flat tappet you are correct.
On our old 512 w/ 10.17:1 and a custom roller saw 112% at 6,000. I was figuring if he is building it to turn 7,500 it better be trick.
Sleeper CP
Big Inch Ford Lover
I don't know if you could port match a rectangle intake to an oval port head.
I did it once with 049's and an Edelbrock TR2X tunnelram, it worked but all I got was 2mph out of it, and I'll tell ya this I would not do it again, 2mph ain't worth all the hours to get that 2mph!...
I'll tell ya this I would not do it again, 2mph ain't worth all the hours to get that 2mph!...
Oh what kind of hotrodder are you,I know guy's that would give up body parts for 2mph
Sleeper CP
Big Inch Ford Lover
9.5:1 and flat tappet you are correct.
On our old 512 w/ 10.17:1 and a custom roller saw 112% at 6,000. I was figuring if he is building it to turn 7,500 it better be trick.
Sleeper CP
Big Inch Ford Lover
For that set up to turn 7500, it'd HAVE to hit 110%+. That's basically my point. It won't.
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