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#1 |
Registered User
Join Date: Mar 2010
Location: Minnetonka, MN
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Horsepower question?
Hi guys,
I have a '75 010 4-bolt 350 in my truck and am wondering what the approximate horsepower now is? I guess the motor came out of a 75 c-20, and it has long tube headers, an edelbrock performer intake, an edelbrock 1406 carb, and HEI. I am not sure about the internals other than it appears to have factory rockers and valve springs. So what do you think she is packing?
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1971 C-20 350/350 Last edited by 05crewcab; 08-01-2010 at 11:33 PM. |
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#2 | ||
"I ain't nobody, dork."
Join Date: Sep 2007
Location: Whidbey Island, Washington
Posts: 8,978
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Re: Horespower question?
Without knowing what cam is in it, and what heads are on it, is a crapshoot...
Stock it was prolly around 250. Gary
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'cuz chicks dig scars... My 1972 GMC 1500 Super Custom (Creeping Death) "long term" build thread. The Rebuild of Creeping Death after the wreck Quote:
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#3 |
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Re: Horespower question?
Heads are casting # 468642 still not sure about the cam, it doesn't sound meaty or anything so i am assuming it is stock.
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1971 C-20 350/350 |
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#4 |
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Location: Kunsan AB, South Korea
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Re: Horespower question?
I agree with around 250hp. However, if you have compression issues, worn rings, etc, it will be less.
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#5 |
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Re: Horespower question?
is that 250hp stock or with the modest goodies i have on it? I dont think i have any compression issues...
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1971 C-20 350/350 |
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#6 |
Senior Member
Join Date: Jan 2003
Location: daytonabeach
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Re: Horespower question?
in 1975 the typical 350 was rated at 185HP so i think that 250HP quote is highly optimistic
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71c-10 350/2004r/4:11 lowered3/4 longbed/dead by hurricane MEANING OF DEATH::::: SOMEBODY ELSE GETS YOUR STUFF DONT BELIEVE EVERYTHING YOU THINK TAKE MY ADVISE;I DON'T USE IT ANYWAY |
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#7 |
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Join Date: Dec 1999
Location: Old Mission, MI, USA
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Re: Horespower question?
The factory rating on that motor was probably about 170 - 175 net hp.
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Tim |
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#8 |
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Join Date: Oct 2009
Location: Leesburg, VA
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Re: Horespower question?
If it has 642 heads it MIGHT have 8.0:1 compression.
![]() Yeah that sucker probably doesn't make 200hp on a good day. But.....there is good news! It really isn't that tough to swap a better set of heads on it and you already have a carb, intake, and headers! |
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#9 | |||
"I ain't nobody, dork."
Join Date: Sep 2007
Location: Whidbey Island, Washington
Posts: 8,978
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Re: Horespower question?
Quote:
![]() Then it MIGHT have 200 with all the "goodies" on there. Gary
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'cuz chicks dig scars... My 1972 GMC 1500 Super Custom (Creeping Death) "long term" build thread. The Rebuild of Creeping Death after the wreck Quote:
Quote:
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#10 |
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Join Date: Oct 2008
Location: Meridian, Idaho
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Re: Horespower question?
they also went from back of crank to rear wheel hp which also made the numbers go down. Im running a similar motor and would say around 220hp with those mods and an rv cam or something similar. As stated they were 165-185 stock on the 4 bolt blocks back then.
Matt
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72 chevy k-10, swb, auto, 35's, rally's, posi, 4" lift, 2.5" old style 40 series flows with headers and crossover pipe and some other stuff!! |
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#11 | |
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Join Date: Mar 2010
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Re: Horespower question?
Quote:
As far as gen 1 350 heads, which ones would a) bolt right up, and b) give me the most increase in the GO pedal?
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1971 C-20 350/350 |
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#12 | |
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Join Date: Oct 2009
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Re: Horespower question?
Quote:
Here's the next question that needs to be asked. What do you want to use it for? Cruiser? Street/strip? Tow rig and work? Does it need to rev to the moon? |
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#13 |
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Join Date: Mar 2010
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Re: Horespower question?
I just dont want to be embarassed when some punk blips the throttle at a stop light...what's that? street/strip??
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1971 C-20 350/350 |
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#14 |
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Join Date: Oct 2009
Location: Leesburg, VA
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Re: Horespower question?
Street strip....on a budget...
http://www.summitracing.com/parts/SUM-162111/ (have them milled to bring up compression) http://www.summitracing.com/parts/WND-8150/ http://www.summitracing.com/parts/LUN-00010LK/ Use the 750cfm carb of your choice. or.............on the REAL cheap...... https://secure.pawengineparts.com/sh...6563&catid=985 https://secure.pawengineparts.com/sh...7199&catid=778 https://secure.pawengineparts.com/sh...703&catid=1469 750 carb of your choice |
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#15 |
I built it
Join Date: Sep 2008
Location: Bakersfield ca
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Re: Horespower question?
isnt a 750 a bit overkill on a 350?
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'72 k10 lwb 454, th400, 205, d44ft, 12b rear, 4in skyjacker, 35x12.5-15 superswampers, 4.56, blazer tank. painless wiring harness '98 dodge 3500 12v 5sp 4x4. the truck that actually runs |
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#16 |
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Re: Horespower question?
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#17 |
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Join Date: Mar 2010
Location: Minnetonka, MN
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Re: Horsepower question?
Thanks for the suggestions Davetopay, but i was thinking something in the get dirty at the junk yard and clean them up range on the heads
![]() Ideally i would like to get 300-350 horse out of my setup. Is that realistic with the block I have if I change the heads to something higher compression and throw in a bigger cam? what about vortec heads? will they just bolt right up. or do I have to change pistons, etc? i found somewhere that the 'high power' rating on my block is 370 from the factory. which factory heads were those?? ...My performance juices are now flowing ![]()
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1971 C-20 350/350 |
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#18 |
Mean Buzzin' Half Dozen
Join Date: Mar 2008
Location: Orlando, Florida
Posts: 1,081
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Re: Horespower question?
With vortec heads you will need a different intake for sure. From what I have been told and have been reading a cam with a max of .480 lift will work. Have been told and have read on the Comp Cams xe268h cam, and it makes good power.
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"War is an ugly thing, but not the ugliest of things. The decayed and degraded state of moral and patriotic feeling which thinks that nothing is worth war is much worse. The person who has nothing for which he is willing to fight, nothing which is more important than his own personal safety, is a miserable creature and has no chance of being free unless made and kept so by the exertions of better men than himself."
MY TRUCK (Now for sale) 1967 C10 SWB Dylan |
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#19 |
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Location: Aurora,Il ..born,raised and still live in the same house
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Re: Horespower question?
my guess would be around 200 HP.
if it was a '71 350 it would be closer to 250 HP. with the vortec heads,intake and the comp cam xe268h you would be around 250-270
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I love stock! Not really into the whole bagged, squished,chopped, drooped,cut, bent,lifted,twisted,split,decked,massaged,tubbed,jacked trend. (o.k. slightly lowered is fine) For the love of god, just drive it before you forget what the truck is supposed to look like !....LOL |
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#20 |
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Join Date: Aug 2009
Location: Auburn
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Re: Horespower question?
Isn't it that it is capable of flowing 750cfm but not necessarily dumping that much all the time? The beauty of a quadrajet is the variable CFM up to 750cfm. With the q-jets' plates over the secondaries, if the engine doesn't need that much air, it can be tuned to never see it.
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#21 |
I built it
Join Date: Sep 2008
Location: Bakersfield ca
Posts: 744
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Re: Horespower question?
when i had my 350 the 600cfm i had got clogged. and since i was finishing up the 454 in the next few days i put the 750edel i had. and after it got moving it was great for power and what not. but off the line it was a dog. and yes i adjusted the acc. pump for best result. once i got the 454 in it was and is great to drive around
btw not saying you are wrong. its just my experience with a 750 on a 350 wasn't spectacular ![]()
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'72 k10 lwb 454, th400, 205, d44ft, 12b rear, 4in skyjacker, 35x12.5-15 superswampers, 4.56, blazer tank. painless wiring harness '98 dodge 3500 12v 5sp 4x4. the truck that actually runs Last edited by 72chevyk10; 08-02-2010 at 01:41 PM. |
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#22 | |
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Re: Horespower question?
Quote:
sorry for all the questions. just trying to make an educated decision.
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1971 C-20 350/350 |
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#23 |
Mean Buzzin' Half Dozen
Join Date: Mar 2008
Location: Orlando, Florida
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Re: Horespower question?
Is that 250-270 estimate for the motor with 165-185 HP ratings stock, or the '71 250 HP rating?
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"War is an ugly thing, but not the ugliest of things. The decayed and degraded state of moral and patriotic feeling which thinks that nothing is worth war is much worse. The person who has nothing for which he is willing to fight, nothing which is more important than his own personal safety, is a miserable creature and has no chance of being free unless made and kept so by the exertions of better men than himself."
MY TRUCK (Now for sale) 1967 C10 SWB Dylan |
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#24 |
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Location: Old Mission, MI, USA
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Re: Horespower question?
Those are basically the same motor. You need to research the difference between gross and net hp.
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Tim |
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#25 | |
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Join Date: Mar 2010
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Re: Horespower question?
Quote:
Anyway, regardless of gross or net hp...i just need more ![]() can anyone answer my question in the thread above? if i go with vortec heads and that comp cam, what else do i need to complete the install?
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1971 C-20 350/350 |
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