How much horsepower for 318?

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7duster4

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I am curious as to how much horses my rebuilt 318 should make.

It's the original 1974 318 in my Duster. Here is what has been done:
-Bored .30 0ver
-New pistons
-Original heads have been ported for a little more flow
-340 valve springs
-340 spec cam
-double roller timing chain
-windage tray
-New pushrods
-ECU orange box
-570cfm Holley 4-barrel street avenger
-Performer intake manifold
-318 manifolds and duel exhausts
-New accel plug wires
-And just the fact that just about everything else is new. Power steering pump, distributor, water pump, etc. People have been telling me that I should be making around 300hp. In a 3,300lb car, I would think it would run into the 14's with no problem. The only negative is for now the 8 1/4, 2:76 gears will ramain in place. I know I need to get something better. Like 3:23's. But that will be next year. From what I was told the compression should be at least 9.0. So I think 300hp isn't out of the question. What does everyone think? Thanks
 
With everything hooked up and running 250-275 HP, the carb and exhaust manifolds and the accessories are whats going to drop the HP down.
 
I agree. Needs more gas ,and definitely more gear or it will be a dog....
 
Also to run the orange box correctly you will need the 1 ohm ballast resistor and the 140001 Accel coil. Then the rpm's will be limited to 6800 rpms. Without the ballast and the coil the rpms will be limited to 5400-5500 as the stock ballast won't let it get any higher than this.
 
The missing factor is the comp. ratio.
The missing performance items for the reat is a possible higher stall to get off the line quicker and IMO, I would go 3.55's for the rear gear and a 26 inch tire. (235/60/15) Add HD rear springs. I grabed my springs from http://www.espo.com/
They were ordered 1 inch higher than stock. Gives the car a good looking mild rake.

You failed to mention headers or not. IMO, a set of headers with 2-1/2 inch exhaust will fit the bill well.

The exhaust shot is Hooker comp (NOT super comp) headers and Jegs exhaust kit for A bodies @ 2-1/2 with there muflers. Sounds nice.

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I have a freind who is really good on carbs. He disassembled mine and told me that I should get some bigger jets and a larger power valve. So I ordered size 70 jets and a larger 6.5 power valve. The reason I am sticking with the manifolds is becasue when I bought the car it had headers on it and were awful. So new ones were installed and were still awful. They hung low and were always knicked and dented up, I hated them, not to mention they looked bad. I know headers are not all that much money, but I have enough money in the engine as it is. Besides nice headers (The ones that are coated) are more expensive. I also heard that a carb with a cfm over 625 or so would be too high for a 318. So I got a great deal on the 570cfm Holley street avenger I mentioned in the first post. If I could find a rear end that was comlpete and cheap I would buy it. I am going to a swap meet in a few weeks and i'll keep my eye opened. When the time comes and I take it down the 1/4 mile I would put on my older tires from the rear. Which are bias plys with good tread. They are a tad bigger than whats on there now.

So no one thinks I would even be able to hit 14.9 O:) O:)
 
I think that you will be hard pressed to, as the 73 Cuda that I had only ran 15.80's and this was with a 340 and a similar setup. But times have changed and things have gotten better by far, so it may be possiable. the only way that I see it is to have a good converter and more gear something like a 3.91 or 4.10.
 
As far as hitting a 14. Here's my 2cents from my car. 3,600lb ebody cuda. 275/60/15 radials. open 2.76 rear. 318, .030, stock/milled j'heads, 9.7:1 compression, performer rpm, headers, out of the box eddie avs ran a 15.0 @ 95mph @ 2,600ft on its first pass. Probably cuda got it into 14s if i could hook back up. one tire fire sucked. (it since has ran 14.0 @ 95 @ 5,200 ft with a gear change, converter and slicks)
 
Just thought I would also add in that the original crank shaft has been milled. Also a 3-angle valve job has been done to the heads. And a new oil pump. I forgot about those.
 
The 570 Street Avenger is more than enough carb. I have a 600 cfm Holley on my 360 and I also have a 725 Demon and a 750 Holley. The two bigger carbs really only make a difference above 4000 rpm and give up throttle response below.

With your set up a bigger carb will only net you worse gas mileage and worse low rpm throttle response.
 
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