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#1
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Horsepower estimate
We're trying to sell our Round Port engine that we bought a while ago. Of course, the first question that prospective buyers are asking is how much HP. We don't know what cam is in it, but here are the other specs:
SRP pistions, 4.155 with a 7cc valve notch Eagle crank, 4.25 sroke Edelbrock 72cc heads Assuming nominal .004 deck height and a .039 compressed gasket thickness I went on Butler's site, used their CR calculator and found the engine to have an astounding 11.67:1 CR with this combo. Any guess on what kind of horsepower/tq this thing makes? We're trying to figure out what to do with it. The CR numbers are scaring some people away. |
#2
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Without knowing what Cam is in it makes things a crap shoot!
I will say that if the motor will idle nice when fully warmed up at no more then like 700 rpm in gear, then it's likely that it will be making no more then 450 hp.
__________________
Wernher Von Braun warned before his retirement from NASA back in 1972, that the next world war would be against the ETs! And he was not talking about 1/8 or 1/4 mile ETs! 1) 1940s 100% silver 4 cup tea server set. Two dry rotted 14 x 10 Micky Thompson slicks. 1) un-mailed in gift coupon from a 1972 box of corn flakes. Two pairs of brown leather flip flops, never seen more then 2 mph. Education is what your left with once you forget things! |
#3
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Do you at least know if the cam is solid roller, hydraulic roller, hydraulic flat tappet, or solid flat tappet
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#4
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Hydraulic roller.
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#5
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Head work? Or stock e-heads? Could be anywhere from 425hp to 535hp I'd say and torque 50+ over those numbers respectively
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#6
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I believe stock E-heads. But not confirmed. Thanks for the replies, we're just trying to figure out what to do with this thing.
I have to give a shout out to a member on here who lives nearby. He sold me a great Quadrajet at a good price and has been helping me along. His handle is GTO Firehawk John. The cars and engines that he has blew my mind. I posted on here for a bit to give him a break from my constant questions. He's spent a lot of time helping me out, I really owe him one. |
#7
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Have you ever done a cranking compression test on this engine? If so what were the numbers.
Stan
__________________
Stan Weiss/World Wide Enterprises Offering Performance Software Since 1987 http://www.magneticlynx.com/carfor/carfor.htm David Vizard & Stan Weiss' IOP / Flow / Induction Optimization - Cam Selection Software http://www.magneticlynx.com/DV Download FREE 14 Trial IOP / Flow Software http://www.magneticlynx.com/DV/Flow_..._Day_Trial.php Pontiac Pump Gas List http://www.magneticlynx.com/carfor/pont_gas.htm Using PMD Block and Heads List http://www.magneticlynx.com/carfor/pont_pmd.htm |
#8
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I got same comp ratio.
The general rule of thumb is that a person can accidently get 500 horse power out of a 455. I would promote that number, if needed. Just a thought.
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1977 Black Trans Am 180 HP Auto, essentially base model T/A. I'm the original owner, purchased May 7, 1977. Shut it off Shut it off Buddy, I just shut your Prius down... |
The Following 2 Users Say Thank You to 77 TRASHCAN For This Useful Post: | ||
#9
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Just tell them you estimate 500 horsepower. It’s easy to find examples like Ken Crocie who dyno tested a 455 with Edelbrock heads that easily made that number.
Then tell them everything you know about the components used and get on with the sale.
__________________
1964 Tempest Coupe LS3/4L70E/3.42 1964 Le Mans Convertible 421 HO/TH350/2.56 2002 WS6 Convertible LS1/4L60E/3.23 |
The Following 3 Users Say Thank You to b-man For This Useful Post: | ||
#10
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Two things, a 461 ci motor, with a Crower hyd cam, 520 lift with 72 cc..E-heads made 500 hp. On pump gas. I think compression work out to 10.75. Not 100 % sure on that. Number were back up at drag strip.
So I’m guessing with hyd roller and that compression, it’s probably around 525-550 hp. .2 no problem with that compression running pump gas. I’m at 11.5 with my 505 and a 739 lift solid roller. No issues what so ever. You can actually run 2 points more compression with aluminum head. And still be safe for pump gas. Most hyd roller cams never see more then 650 lift. That motor to replace or build today from scratch is around $12,000.00 complete. PS: the E-Heads had no port work, just a clean up and valve job checked.
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Last edited by Gach; 04-12-2023 at 02:30 PM. |
#11
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You just can’t get around that basic fact that especially for a non purpose built flat out race motor, no less a street strip motor that for every 100 Hp you plan on making your going to need to run .100” of lift.
__________________
Wernher Von Braun warned before his retirement from NASA back in 1972, that the next world war would be against the ETs! And he was not talking about 1/8 or 1/4 mile ETs! 1) 1940s 100% silver 4 cup tea server set. Two dry rotted 14 x 10 Micky Thompson slicks. 1) un-mailed in gift coupon from a 1972 box of corn flakes. Two pairs of brown leather flip flops, never seen more then 2 mph. Education is what your left with once you forget things! |
#12
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Quote:
A degree wheel and dial indicator setup is not an impossible thing to do, to get cam information...
__________________
1977 Black Trans Am 180 HP Auto, essentially base model T/A. I'm the original owner, purchased May 7, 1977. Shut it off Shut it off Buddy, I just shut your Prius down... |
#13
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Quote:
.750 lift made 900hp on pump gas. I don't think that's a rule at all, just coincidence it might work on some combos |
#14
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Your talking a race motor making a high level of VE, I am not just as a clearly stated, or I thought I clearly stated.
__________________
Wernher Von Braun warned before his retirement from NASA back in 1972, that the next world war would be against the ETs! And he was not talking about 1/8 or 1/4 mile ETs! 1) 1940s 100% silver 4 cup tea server set. Two dry rotted 14 x 10 Micky Thompson slicks. 1) un-mailed in gift coupon from a 1972 box of corn flakes. Two pairs of brown leather flip flops, never seen more then 2 mph. Education is what your left with once you forget things! |
#15
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Quote:
Quote:
Could the OP measure his current valve lift and come up with an answer to his question? Last edited by PAUL K; 04-12-2023 at 06:19 PM. |
#16
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Quote:
I think your rule is based on coincidence, most street cams have .500 to .600 lift, most engines make 500 to 600 hp. That's just coincidence. Anyway, sorry to sidetrack the thread. |
#17
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I calculate the min valve lift using ci, rpm, VE%, and valve size. You could say in someways I am looking for a needed curtain area.
Stan
__________________
Stan Weiss/World Wide Enterprises Offering Performance Software Since 1987 http://www.magneticlynx.com/carfor/carfor.htm David Vizard & Stan Weiss' IOP / Flow / Induction Optimization - Cam Selection Software http://www.magneticlynx.com/DV Download FREE 14 Trial IOP / Flow Software http://www.magneticlynx.com/DV/Flow_..._Day_Trial.php Pontiac Pump Gas List http://www.magneticlynx.com/carfor/pont_gas.htm Using PMD Block and Heads List http://www.magneticlynx.com/carfor/pont_pmd.htm |
#18
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Gez guys, I am just saying it’s a pretty good rule of thumb.
If your running .500” lift and your making 580 Hp out of a mild street motor then I am happy to be wrong to that side of equation .
__________________
Wernher Von Braun warned before his retirement from NASA back in 1972, that the next world war would be against the ETs! And he was not talking about 1/8 or 1/4 mile ETs! 1) 1940s 100% silver 4 cup tea server set. Two dry rotted 14 x 10 Micky Thompson slicks. 1) un-mailed in gift coupon from a 1972 box of corn flakes. Two pairs of brown leather flip flops, never seen more then 2 mph. Education is what your left with once you forget things! |
#19
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Serious question can you provide lobe specs that has duration at .050 between 235 to 245 (the most common duration used for 500-600 hp engines) that doesn't automatically produce .500 to .600 lift when combined with the most common rocker ratio of 1.5 to 1.65? Your rule is just a coincidence. And when give examples that don't fit your rule you write it off as a race engine.
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#20
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Not saying you should put this price on it, its up to you. But one with just about same spec’s sold for $9500.00 on Facebook deal.
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