Big Blocks

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yellow73dart said:
eaglesguy1981j , I'm running a .040 over 440 with the stock crank and rods . edelbrock performer rpm heads with the 83cc combustion chambers and the same weind t-ram w/ 2-600cfm carter afb's . Its very street friendly and I'm in the low 11's . I'm running a hydraulic flat tap cam . I'm at work and don't have the cam specs but I don't see why you couldn't get down into the 10's . The stealth heads look like the same specs as the edelbrocks . I wish I knew about them when I bought mine . I could have saved some money .
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Ive done a bit of homework on the heads. The Stealth and Eddys heads flow exactly the same @ .600 lift there both rated at 290cfm and the stealths are almost half the cost. When you get time Id love to see your cam specs. That seems to be the missing peice. I cant decide. Lots of guys telling Im leaving alot on the table by not going roller. But the cost of a roller vs a flat tappet is my decision maker.
 
BJR Racing said:
The 440 has 11.76:1, the #'s are rear wheel and generally when the cams increase in lift and duration the overlap increases also, what I found is that as OL increases the detanation becomes more of a problem so timing has to be reduced.
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Is this at a higher rpm, more cyl fill from increased scavenging?

What cam specs are we deviating from that would lead to this when you already have 11.76?

Is less timing , to extent, a bad thing?
 
Actually at high RPM's the cylinder leans out due to over scavenging due to overlap, and this causes the detonation, making a lean mixture.
Cam specs. in the 100+ overlap and durations in the 265+ @ .050.

What happends is when the timing is right to make the car leave and run then becomes too much on the top end and crates a lean condition. But if you retard the timing from the get go then the car becomes lazy and won't run down low. I just went through this on my 344 engine with 107* of overlap, and it burned every piston, on alcohol.
 
Sounds like a chevy problem with how much better the exhaust is over their intake flow=over scavenging that, at a point, pulls the mix right out of the cyl and out the exhaust.

Maybe play with the I/E ratio a bit and see what happens?

Or easier, the timing curve.
 
1wild,
It would be easier to just decam the engine, and thats what I intend to do. I'll use that cam in a larger engine like a 360 .030 with large heads, this way the duration will get eat up a bit from the larger CI's. I ran across this same thing with the MP .590 in a 400 years ago. And when I dropped the cam size back the car responded in kind.
 
The Hughes cam looks like it would be the better of the 2 you have listed, but why are you going to use a 440 source heads? If they are the same flow as the Eddy's your not going to get the performance out of them that you think, as the low lift flows are down a good bit from what they really need to be. I think that you would be better off with a good set of factory castings with smaller port runners, this will give you better port velocity and a stronger signal to the carbs. It will make it easier to tune also.
 
BJR Racing said:
The Hughes cam looks like it would be the better of the 2 you have listed, but why are you going to use a 440 source heads? If they are the same flow as the Eddy's your not going to get the performance out of them that you think, as the low lift flows are down a good bit from what they really need to be. I think that you would be better off with a good set of factory castings with smaller port runners, this will give you better port velocity and a stronger signal to the carbs. It will make it easier to tune also.
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I always heard that the heads are where you make your power. I dont think that the stock heads will make the kind of power I want without alot of work. Money that I could invest in a good set of aftermarket heads. If you have a better cam suggestion let me know. I sorta wanna go roller so I dont leave power on the table
 
I would use a XR292HR-10 Comp Cams, factory heads can make up to 750 HP with the right work. We did this with the same basic setup your going after. The heads were 452's with 2.14/1.81 valves and a mild port job. Nothing drastic.
 
BJR Racing said:
I would use a XR292HR-10 Comp Cams, factory heads can make up to 750 HP with the right work. We did this with the same basic setup your going after. The heads were 452's with 2.14/1.81 valves and a mild port job. Nothing drastic.
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http://www.compcams.com/Cam_Specs/CamDetails.aspx?csid=1444&sb=2 This cam? That looks like a good cam. I do plan on running 4.10s with a 3200 stall. Now what lifters do I need. Sorry for all the questions. But cam specs and such is beyond my knowledge. Dose your shop do this kind of head work? Im only asking to get a idea of what it cost to have done.
 
8921-16 are the lifters. Yes thats what we do, race engines and heads. You would be looking at $850.00 + parts for a set of heads like that.
 
OK I'm trying hard to understand this. So I'm between Iron vs Stealths. What does heads coming from you get me that the stealths dont have? Just an estimate what kind of power could I expect to make with this build. Using your heads vs The source heads. Using that hughs cam. And all the other specs I gave you.
 
My heads will have alot more flow where the cam is being run at where as the Stealth heads will have to have some work to them to get them to flow like my heads. Also too my heads will have more port velocity than the Stealth heads and will flow more for the same money. The Stealth heads are a copy of the Eddy heads, this is what is advertised from Edlebrock for there heads, and this is what my heads flow for the same money, less parts.

Eddy Heads with 210 cc runners
lift...........Int
.100.........79
.200........145
.300........209
.400........254
.500........278
.600........290
.700........292

my heads with 185 cc runner
.100.........86
.200........178
.300........226
.400........259
.500........293
.600........298
.700........300

this is with a 2.14 intake valve in both heads
 
And people have been wondering why I recomend iron heads and a good porter for years.......
 
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