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HP/TQ numbers

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Red20 View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Red20 Quote  Post ReplyReply Direct Link To This Post Topic: HP/TQ numbers
    Posted: Apr/18/2018 at 5:22pm
Just a quick survey of what the experienced engine builders think my engine may be doing. I haven’t had it on a dyno, but I’m curious how much (little?) power you guys estimate I’m making.

360 .030 over
TRW forged factory style dish pistons
512 heads light exhaust port smoothing
Harland Sharp stud mounted rockers w/guide plates
TINY Performer Cam
AirGap manifold
Quick Fuel 680 cfm carb, stock jetting still
Hedman 1-5/8 primary long tube headers
MSD 6a and distributor

I’d love to be around 375/420, but I don’t think I have the cam or air flow for that. I can’t afford aluminum heads and custom tuned headers, but a cam swap and maybe some light garage porting and port matching is doable. Maybe a good small time cylinder head guy will give me a killer deal one day.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote 6768rogues Quote  Post ReplyReply Direct Link To This Post Posted: Apr/18/2018 at 6:07pm
Mine is vaguely similar but with stock heads and a little more cam (balanced, too) and my engine guy said it should be somewhere between 330 and 340 HP. I was not as concerned about a lot of HP, I was more concerned that it has stump pulling torque as soon as I hit the throttle. It does that, right off idle instant explosive power. High HP usually comes from high RPMs, and for the street I am not concerned about going more than 5000 RPM. I like off the line torque that pushes me back in the seat. To me, that is where the fun is on the street.
HP=(torque x 5250)/RPM. Increasing RPM is an easy way to jack up the HP. You didn't mention balancing, and without it and major airflow you are not likely to see the kind of RPMs that high horsepower takes.
The rear end gearing has a lot to do with how your car performs.
My opinion, I am not an engine expert. However, I am an expert about my opinion.


Edited by 6768rogues - Apr/18/2018 at 6:13pm
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Located usually near Rochester, NY and sometimes central FL.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Red20 Quote  Post ReplyReply Direct Link To This Post Posted: Apr/18/2018 at 6:10pm
It’s a driver, so yeah, instant torque is certainly enjoyable. Yes, the engine is fully balanced.
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1973 Hornet Sportabout X "yellajack" - 360/727/TracLoc DAILY DRIVER
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Post Options Post Options   Thanks (0) Thanks(0)   Quote 6768rogues Quote  Post ReplyReply Direct Link To This Post Posted: Apr/18/2018 at 6:14pm
My guess, low 300s HP. Plenty for street fun, reliability, and long distance capabilities. I think your carb is the right size, too. Nice combination.


Edited by 6768rogues - Apr/18/2018 at 6:17pm
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Ralph G. Quote  Post ReplyReply Direct Link To This Post Posted: Apr/18/2018 at 7:25pm
My 390 is .040 over, Holley 750, Air-Gap manifold, HEI distributor, undercar headers and Isky 262 Supercam. Breaking in the cam on the dyno it made 323 h.p. @ 4500 r.p.m. and 441 lbs/ft of torque @ 2900 r.p.m. Between 2500 r.p.m. (lowest speed at which it was recorded) and 4200 r.p.m. it never was less than 400 lbs/ft of torque. It is exactly what I wanted -- smooth, torquey, unfussy. Even with a close-ratio 4-speed and 3.15 rear it can be easily driven from a dead stop in 3rd gear.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Red20 Quote  Post ReplyReply Direct Link To This Post Posted: Apr/18/2018 at 8:24pm
Sounds fun, Ralph G. I’ve been considering the Summit 8601 cam.
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1973 Hornet Sportabout X "yellajack" - 360/727/TracLoc DAILY DRIVER
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Post Options Post Options   Thanks (0) Thanks(0)   Quote WesternRed Quote  Post ReplyReply Direct Link To This Post Posted: Apr/18/2018 at 8:29pm
I would have guessed around 300, if chasing 400HP, you will probably need to increase compression, add a decent cam and do some headwork.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Red20 Quote  Post ReplyReply Direct Link To This Post Posted: Apr/18/2018 at 8:31pm
Originally posted by WesternRed WesternRed wrote:

I would have guessed around 300, if chasing 400HP, you will probably need to increase compression, add a decent cam and do some headwork.


I agree with you completely.

Ideally a 400HP / 450+TQ daily driver setup getting 15+ mpg would be a blast. Not that easy on a budget. However 300hp and torque right off idle is enough to have a fun driver.

Edited by Red20 - Apr/18/2018 at 8:35pm
1969 Javelin SST "Screamin' Banana" - Totaled Feb 2018
1973 Hornet Sportabout X "yellajack" - 360/727/TracLoc DAILY DRIVER
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Sonic Silver Quote  Post ReplyReply Direct Link To This Post Posted: Apr/18/2018 at 8:33pm
Originally posted by WesternRed WesternRed wrote:

I would have guessed around 300, if chasing 400HP, you will probably need to increase compression, add a decent cam and do some headwork.
That's about what I was thinking, but I was afraid that I would make him mad, so I didn't say anything. 
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Red20 Quote  Post ReplyReply Direct Link To This Post Posted: Apr/18/2018 at 8:37pm
Originally posted by Sonic Silver Sonic Silver wrote:

Originally posted by WesternRed WesternRed wrote:

I would have guessed around 300, if chasing 400HP, you will probably need to increase compression, add a decent cam and do some headwork.
That's about what I was thinking, but I was afraid that I would make him mad, so I didn't say anything. 


Hold on now! I don’t have a history of getting mad over the interwebs, haha! I can name a few guys who do...
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