69 Dart, 73-360, 4 speed, 3.55’s, primarily street driven.
KB107’s 30 over, estimated comp 9.5 to 1 pending head gasket thickness on pump gas. Shootin for approx.. 400 hp.
Stock crank and rods.
Stock heads/valves, valve job, new guides and mild porting. Eddy Performer RPM intake.
Comp Cams Pro Magnum Roller Rockers/Arms/Shafts 1622-16, 1.5 ratio.
Need recommendations on cam selection.
I agree, SOMEBODY missed the mark. I'm not the guy who recommended the 284 cam
In fact, I didn't recommend a cam at all.
I merely pointed out the issues,of his combo, should he chose to run a 284 in it.
You just can't run that cam with a 4 speed on the street with 3.55s.
Well you can but I doubt you'd be happy past the first week. At 9.5Scr it will be 318 soft up to about 2500/3000, and a pos under 1500/12mph
Been there done that, would never do it again.
You want to run that 284? Then;
Get you some aluminum heads, and run the pressure up to at least 185psi.
Put a "lazy" timing curve in it delayed to 32*@3400.tune it for 87E10. Run about 12 initial,
Then run 4.30s minimum with that 2.66box; or 3.73s with the 3.09box
Then you could drag her down to 4mph@700rpm, if she has enough torque, hah,and if she doesn't get all jumpy on you. The best cure for that is less timing, and more gear,lol. ....................... And don't floor it from down there.
BTW; that 185psi will be 11.3 Scr.
But I'll tell you a secret;
that 185psi will make so much power, you won't need that 284 cam.
In fact, you will be many times happier with a 268 cam and 185 psi. This will allow you to drop the Scr to 10.5 and still get 180 psi.
But If I did that, I'd tighten the LSA up to 102
,EDIT; should read 104,and install it at 100, for an ICA of 54*,and that would allow me to drop the Scr to 10.3, and still have pressure over 180. Aand,what that would do, is make funtastic torque,like a 440Magnum of yesteryear, allowing the use of those 3.55s even with the 2.66box... Aaand the 118* of power-stroke extraction, means it can be tuned to get decent hiway mileage. Aaaand the 68* of overlap, means a nice little power bulge somewhere around 5000rpm with headers and a free-flowing exhaust. That's 35mph in 3.09low,40 in 2.66low, and 56 in 1.91 second, all with the 3.55s; And I'll tell you, the biggest tires you can fit in even mini-tubbed 69 Dart wells, will not ...not spin, all the way thru two gears, no matter how crappy the tune, to perhaps 70 plus mph.
Hey wait, that sounds an awful lot like my 367, which has been a DD since 1999, and has gone 93 in the 1/8 @3467 pounds. Unfortunately My cam only has 105* of power extraction, and no matter how hard I try, I can't make 30mpgUs out of that. However, I think I could with the 268/276/102
(again should read 104) ....... with an overdrive. I mean it wouldn't be the first time I tickled 30s, point to point.
So tell me why I need a 284 cam again?
Oh I remember, iron X-heads.........
Boy I'd drop those in a heartbeat.
About the max pressure you can run with iron is 165,and with open-chamber heads, that's pushing it, and premium gas may not be around much longer. So perhaps 160 is a better max target. Now couple that with a late closing intake like the 66* of a 284, and there's nothing left for take off with a 266x3.55 starter gear, and still nothing by 20 mph, for normal sane driving. Been there done that, ain't going back. Around town, I was always deep into the throttle, and it sucked so much gas I could hardly afford to drive it.
