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| Up late and I can't sleep, so I have an HP question? https://slantsix.org/forum/viewtopic.php?t=55969 |
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| Author: | TonyPgh [ Thu Aug 14, 2014 9:42 pm ] |
| Post subject: | Up late and I can't sleep, so I have an HP question? |
Just curious about horsepower. Okay, so right now I have 145HP. 225/6 Now keep in mind, I am only asking for an approximate HP amount. If I get head work done, shaved, bigger valves...etc. A bigger cam Dual Exhaust Larger carb...2 barrel or 390 Holley 4 barrel? Can't think of anything else I can do, but I will be changing to 3:55 gears to help out. Can anyone tell me about how much HP those mods would get me up too? Just approximate. Please don't bash me. I am still learning these motors---> 
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| Author: | /6 Matt [ Thu Aug 14, 2014 10:50 pm ] |
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My guess is 160 @ crank. Net not gross |
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| Author: | TonyPgh [ Fri Aug 15, 2014 6:28 am ] |
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Oh crap. All the work, and only about 15 hp gain. Thats why I asked. Thank you. |
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| Author: | TonyPgh [ Fri Aug 15, 2014 6:30 am ] |
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Oh crap. All the work, and only about 20hp gain. Thats why I asked. Thank you. |
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| Author: | slantzilla [ Fri Aug 15, 2014 7:27 am ] |
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Actually, 145 is a pretty generous starting number. A normal Slant is closer to 110-115ish. In reality you would be making about a 30% gain, and that ain't hay. 160ish would be a good ballpark guess unless you are really doing something good with the head and camshaft. Speed costs money, how fast can you spend? 
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| Author: | TonyPgh [ Fri Aug 15, 2014 8:20 am ] |
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You have a good point. I looked mine up for my 65 and it showed 145. I forget when the HP lowered on them. I was going to go with a nice cam and shave the head and bigger valves. I was hoping to get around 200hp. |
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| Author: | Joshie225 [ Fri Aug 15, 2014 8:32 am ] |
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What's your current 1/4 mile ET and MPH? What do you want it to be? I took over 2 seconds off my '67 Valiant's ET without a cam change or any bottom end work. I didn't do a gear change either. I had the same 3-speed and 3.21 gears. It was all head work, intake, carb and exhaust. No headers either. 17-flat isn't impressive, but it feels much better than a 19.2. |
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| Author: | TonyPgh [ Fri Aug 15, 2014 9:42 am ] |
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Quote: What's your current 1/4 mile ET and MPH? What do you want it to be? I took over 2 seconds off my '67 Valiant's ET without a cam change or any bottom end work. I didn't do a gear change either. I had the same 3-speed and 3.21 gears. It was all head work, intake, carb and exhaust. No headers either. 17-flat isn't impressive, but it feels much better than a 19.2.
Taking off 2 seconds is actually pretty good!!Maybe I should have explained myself better. I just got the car about 2 weeks ago. I hopefully will have it running right by the weekend, I have another thread going with it sputtering. Ugh!! I was trying to gain knowledge now, so over the winter, I can start buying parts, and get it together for next spring, while it is down for five months. I was thinking, Dutra Dual Exhaust Intake and Small 390 4 barrel Cam Headwork, much as possible And of course I was going to switch to 3:55 gears. Not sure what gears I have in there now. I do have that larger rear end, with no pumpkin cover. 8 3/4? I checked in quite a few places, it is saying I have 145hp@4000rpm. I have no way of verifying that. For except the specs on the internet for a 1965 Belvedere II, with a 225. It is the original engine, according to the numbers. I also find it hard to believe my car only weighs 3100lbs. Looks heavier. |
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| Author: | 1974duster kev [ Fri Aug 15, 2014 12:44 pm ] |
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My old NA motor started doing 12.0 or 11.9@60 in the 1/8 mile. 238@50 duration 108lsa 510 lift 10:1 compression and head work fresh rebuild stock internals except 40 over pistons clifford shorty header/dual exhaust 390cfm4bbl/clifford intake 3.73 gear in an 8 3/4 posi 3,000rpm converter Same duster 9.6@73 after these upgrades could have used more carb I believe since I had it jetted up so much. So whatever that equates into a horsepower gain. |
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| Author: | TonyPgh [ Fri Aug 15, 2014 7:04 pm ] |
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Thanks, outstanding! Thats what I was asking for, some ideas. I have done a lot of 350 Chevy's, Beetle engines. But never a slant. I took mine for a ride tonight. I must admit. They seem to have some torque! |
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| Author: | DKD [ Fri Aug 15, 2014 8:40 pm ] |
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It depends how much you shave the head, how you port it when you install the bigger valves, what cam you choose and what carb and intake. Certainly 200 is well with in your grasp. One HP per cube would be minimum goal I would think. Your choice of exhaust will also determine that. I would go for a 500 Holley rather then the 350. remembering Holley two barrels are rated at a different vaccum drop then four barrels and tend to be a bit optimistic in numbers CFM. IE a 500 2bbl is essentially 1/2 a 750 4bbl and so using the 4 bbl vacuum drop rating would actually only be about 375 CFM which is still a bit on the small side considering using Dons law double the cubic inch to get approx. CFM would give 450cfm using the four barrel Holley vacuum drop rating. Just some thoughts from /6 I have played with over the last 40 years or so. don 4ur info. Holley 2 BBls are rated a 3inch vacuum drop. Holley 4 bbls at 1.5 inch vacuum drop |
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| Author: | classic ap6 [ Sat Aug 16, 2014 3:25 am ] |
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I recently dynoed mine and it was getting 140 at the wheels Head work was very mild porting and larger valves. Static comp is about 9:1 Camshaft has about 220 duration at 50 and about 44 lift, nothing huge I was running a 500 holley on the dyno but have since gone to a 350 I think I could have improved on this as the timing wasn't right and the motor overheated on its pass Cheers |
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| Author: | wjajr [ Sun Aug 17, 2014 7:12 pm ] |
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I ran 1/8th mi in 10.3 sec. @ 68.3 mph with mostly all stock full dress 67 Dart ragtop a few years ago that is probably a bit on the heavy side + 225 lbs. of operator lard. 390 CFM Holley 4160, Clifford 4V intake Head shaved to give 9.5:1 compression, oversized valves, ported & gasket matched. Camshaft: 0.236* exhaust duration @ 0.050â€, 0.324†lift at lifter or 0.460 at valve 0.235* intake duration @ 0.050â€, 0.321†lift at lifter or 0.444 at valve 30 over stock pistons, and unknown low end work . Clifford Shorty headers, duel 2†to rear bumper 904 Torqueflite with shift kit, 2600 stall converter, 8 ¾†Suregrip with 3.55:1 gear, and 24.5 inch diameter BFG Radial TA tires. Power steering, KH disk brakes, 10 rear drums. Could it do better, yes. Had I known what my cam was when I ordered the converter, a little bigger carb, more compression, and more experience leaving the line it would be faster. Currently car is more suited for ¼ mile; power band is too high & stall too low for 1/8 mile. Previous owner built it for ¼ mile track, raced it with 4.11 gears, and it was much faster. |
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