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Author
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Topic: To what RPM
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Fastymz
Moderator Posts: 13447
From: Reno Nv USA MEM#1240
Registered: Apr 2001
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posted 12-03-2003 04:49 PM
   
I went talked with a local guy that builds mostly holley carbs. And he dails in dist's too. He and the machine shop and most people ask to what RPM do you want to turn your motor. I always feel like a dumb a$$ and set there and say I'm not sure ???
I understand you want to build the motor to build power around where you'll use it right ?So in that case whats the best rpm range for a mostly street car, with some strip time.
I told the carb guy 6000rpm would be tops, he said if thats all then my 600cfm holley would be just fine, maybe a double pumper 650 at most if I needed alittle at the track. The guys name is Bob Oliver, Competion Carburetion anyone ever heard of the guy ? I keep getting different storys as to what rpm to build the motor for. To me the more power it makes down low is better for the street and higher is better for racing. So if I can make most of my power between 3500-5500 would seem like the best of both worlds? Whats do you guys think ?
I'm going to change the convertor to a 10" model, and go with 3.80 gears and 26" tall tires, all in the near future. After the motor is all paid for that is.  So please give me your opinions. If it makes a difference I want to drive the car to sac. Which is about a 150mile trip each way.A once or twice a year. And drive it to the drags which is a good 45 miles or more away. Thanks Ron ------------------
SCOOP 2.26 60'S
14.9 @ 90.86MPH 65 coupe,351w,C4,Big Boss 429 hood scoop,8" 3.40 TracLoc. My Pics
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Tea'sGrabber
Gearhead Posts: 237
From: Seattle, Wash.
Registered: Feb 2003
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posted 12-03-2003 05:23 PM
It takes torque Ron!!!! Make as much torque as you can that stays with you all the way thru the the power band.... You're right when you say 3500 to 5500 rpms... On the street, 6000+ rpms doesn't make telephone poles any softer.... Cubic H.P.= Cubic $$'s !!! I'd get your bullit done then start picking peoples brains about the carbs,gears,converters.... There are so many variables.... I was told that a 650 was all my motor needed..... 15 carbs and 5 dyno sessions later and a modified 750 that flows 1026 cfm made the most power... and I'm 306 cu in's....Good to see ya back!!!!! Send your stuff up here... We'll build ya an ass pinner!!!! ------------------
Todd 71 Mav Grabber All orig 306 cu.in. Cast Iron heads. Carillo Rods.Best et. 10.71 @ 124 thru the mufflers.
http://mustangsandmore.50megs.com/MembersPics/TeasGrabber.html
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Dubz
Gearhead Posts: 906
From: Manitoba Canada
Registered: Oct 2002
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posted 12-03-2003 05:31 PM
i've been told to build to about 6000 for street by a couple rodders around here. Maintain good low end power and good midrange3000-5000 is what i'm building for, but your car is lighter, so it doesn't need as much low end torque to motivate it.
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V-8
Gearhead Posts: 198
From: Turkey/Istanbul
Registered: Dec 2003
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posted 12-03-2003 06:16 PM
you can turn your engine 7000rpm with stock bottom.but the most important think is your budget...
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V-8
Gearhead Posts: 198
From: Turkey/Istanbul
Registered: Dec 2003
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posted 12-03-2003 06:27 PM
6500rpm is good in street I think.
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steve'66
Gearhead Posts: 7010
From: Sonoma,CA,USA
Registered: Mar 2000
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posted 12-03-2003 11:10 PM
Ron,I agree with 6500+ rpm for a 351w! Maybe a little less if you're building a stroker. I have a 6800 rpm limiter on the 408w and she's hit 6600 a few times.  The more rpm you can make power at the more h.p. you'll produce. Time to crank it up a couple notches.  SteveW
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Fastymz
Moderator Posts: 13447
From: Reno Nv USA MEM#1240
Registered: Apr 2001
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posted 12-04-2003 12:53 AM
So does anyone else think that a 600 VS would be good for a 351w with at least 10-1 compression and a 282s cam ?How do you build the motor for the most torque with little drop off ? SteveW 6500 isn't to much rpm to make good power on the street too? ------------------
SCOOP 2.26 60'S
14.9 @ 90.86MPH 65 coupe,351w,C4,Big Boss 429 hood scoop,8" 3.40 TracLoc. My Pics
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Dubz
Gearhead Posts: 906
From: Manitoba Canada
Registered: Oct 2002
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posted 12-04-2003 02:51 AM
i was having issues choosing between a 600 and a 750 so i picked up a 670VS for my 351W
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V8 Thumper
Gearhead Posts: 3936
From: Orange, Ca. United States of America
Registered: Dec 2001
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posted 12-04-2003 08:18 AM
351W... long rods and long stroke, awesome rod/stroke ratio, that thing will be a torque monster down low  It'll make 430-450hp with a torque curve flat as a board I personally would chose a 700-750 carb for a weekend-only car ------------------
1965 GT coupe, 333ci aluminum headed/solid cammed stroker, four speed, 3.70:1 9" All Blue Oval, no blue bottle
http://mustangsandmore.50megs.com/V8Thumper.html
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V8 Thumper
Gearhead Posts: 3936
From: Orange, Ca. United States of America
Registered: Dec 2001
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posted 12-04-2003 08:38 AM
quote:
Originally posted by V8 Thumper:
It'll make 430-450hp
...in good air, that is. What altitude are you at? What is Fallon at? Maybe a 600-650 with more timing would be the slick ticket
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1965 GT coupe, 333ci aluminum headed/solid cammed stroker, four speed, 3.70:1 9" All Blue Oval, no blue bottle
http://mustangsandmore.50megs.com/V8Thumper.html
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Fastymz
Moderator Posts: 13447
From: Reno Nv USA MEM#1240
Registered: Apr 2001
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posted 12-04-2003 01:11 PM
Todd it's about 4000 feet at Fallon.Anyone else ever heard of this guy ??
Bob Oliver, Competion Carburetion
He really seems to know his stuff. He's real big on NOT using a big carb. Told that a 750, even a VS would be more then I'd ever need on the street. But at the track I could use a 650DP. ------------------
SCOOP 2.26 60'S
14.9 @ 90.86MPH 65 coupe,351w,C4,Big Boss 429 hood scoop,8" 3.40 TracLoc. My Pics
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Fastymz
Moderator Posts: 13447
From: Reno Nv USA MEM#1240
Registered: Apr 2001
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posted 12-04-2003 01:13 PM
Wouldn't you build a motor for a flat torque curv, by using the right cam and heads,and compression ?If so what are those?
Or do you just take the best guess you can and see what you end up with. So many opinions out there and a lot of them are right. ------------------
SCOOP 2.26 60'S
14.9 @ 90.86MPH 65 coupe,351w,C4,Big Boss 429 hood scoop,8" 3.40 TracLoc. My Pics
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SteveLaRiviere
Administrator Posts: 36138
From: Saco, Maine
Registered: May 99
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posted 12-04-2003 02:28 PM
quote:
Originally posted by Fastymz:
I keep getting different storys as to what rpm to build the motor for. To me the more power it makes down low is better for the street and higher is better for racing. So if I can make most of my power between 3500-5500 would seem like the best of both worlds?
Sounds like you know what you're looking for already. Another big thing to consider is that the higher the rpms you turn, the shorter your engine's life span will be, and that's important for a family man on a budget, right? Big rpms = big mechanical violence. Dr Steve's Rx: Forged 10:1 pistons, CompCams 270H cam, good internals, and you'll be having a ball drag racing your mid-high 12 second car for a long time. ------------------
'70 Mustang Mach 1 351C 4V/FMX/3.25 Open
'70 Mustang Convertible 250 I6/3 speed/2.79 Open
'72 Mustang Sprint Coupe 351C 4V/FMX/4.30 Trac Loc
'94 F-150 XL 5.8L/E4OD/3.55 Limited Slip
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Fastymz
Moderator Posts: 13447
From: Reno Nv USA MEM#1240
Registered: Apr 2001
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posted 12-04-2003 02:32 PM
quote:
Originally posted by SteveLaRiviere:
Another big thing to consider is that the higher the rpms you turn, the shorter your engine's life span will be, Big rpms = big mechanical violence.Dr Steve's Rx: Forged 10:1 pistons, CompCams 270H cam, good internals, and you'll be having a ball drag racing your mid-high 12 second car for a long time.
Steve thats what a lot of people have told me. Sounds like a blast to me. The other side is I feel like I only have one chance to do this right. I'd hate to wish I did alittle more cam, heads, POWER later.
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SCOOP 2.26 60'S
14.9 @ 90.86MPH 65 coupe,351w,C4,Big Boss 429 hood scoop,8" 3.40 TracLoc. My Pics [This message has been edited by Fastymz (edited 12-04-2003).]
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SteveLaRiviere
Administrator Posts: 36138
From: Saco, Maine
Registered: May 99
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posted 12-04-2003 02:46 PM
Once you get a solid foundation built, a cam change is a saturday morning away.------------------
'70 Mustang Mach 1 351C 4V/FMX/3.25 Open
'70 Mustang Convertible 250 I6/3 speed/2.79 Open
'72 Mustang Sprint Coupe 351C 4V/FMX/4.30 Trac Loc
'94 F-150 XL 5.8L/E4OD/3.55 Limited Slip
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V-8
Gearhead Posts: 198
From: Turkey/Istanbul
Registered: Dec 2003
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posted 12-04-2003 02:52 PM
what about cylinder heads! which head on your 351w?
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V8 Thumper
Gearhead Posts: 3936
From: Orange, Ca. United States of America
Registered: Dec 2001
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posted 12-04-2003 02:56 PM
Too true! When doing my Papa's cam swap, it took all weekend  because there was ALOT of cleaning, polishing, painting, and other crap to do while it was all apart. When I did mine just a short while ago, did it in a day (an easy day at that) since it's fresh and still very clean I still like BIG rpm's  ------------------
1965 GT coupe, 333ci aluminum headed/solid cammed stroker, four speed, 3.70:1 9" All Blue Oval, no blue bottle
http://mustangsandmore.50megs.com/V8Thumper.html
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Fastymz
Moderator Posts: 13447
From: Reno Nv USA MEM#1240
Registered: Apr 2001
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posted 12-04-2003 03:13 PM
V-8 I'm going with the RPM heads with 2.02 valves.Todd, I've never had a motor that I could take over 6000rpm. So I'm alittle gun shy. ------------------
SCOOP 2.26 60'S
14.9 @ 90.86MPH 65 coupe,351w,C4,Big Boss 429 hood scoop,8" 3.40 TracLoc. My Pics
IP: Logged |
V-8
Gearhead Posts: 198
From: Turkey/Istanbul
Registered: Dec 2003
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posted 12-04-2003 03:48 PM
nice scoop man! can you see your front easy while traveling .it seems tall.
your lucky you but 351w in it.
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V-8
Gearhead Posts: 198
From: Turkey/Istanbul
Registered: Dec 2003
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posted 12-04-2003 03:53 PM
you can turn more rpm. in 2002 ? have got 540-541 lift,240-246 0.050,110lsa comp cams hyd. flat tapped cam and trw 13cc cup forged pistons (9.3:1) it was turning 6500![This message has been edited by V-8 (edited 12-04-2003).]
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V8 Thumper
Gearhead Posts: 3936
From: Orange, Ca. United States of America
Registered: Dec 2001
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posted 12-04-2003 06:41 PM
quote:
Originally posted by Fastymz:
Todd, I've never had a motor that I could take over 6000rpm. So I'm alittle gun shy.
So was I ------------------
1965 GT coupe, 333ci aluminum headed/solid cammed stroker, four speed, 3.70:1 9" All Blue Oval, no blue bottle
http://mustangsandmore.50megs.com/V8Thumper.html
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grandestang
Gearhead Posts: 256
From: Lake Bluff, Illinois USA
Registered: Jan 2003
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posted 12-05-2003 04:07 PM
quote:
Originally posted by Fastymz:
V-8 I'm going with the RPM heads with 2.02 valves.Todd, I've never had a motor that I could take over 6000rpm. So I'm alittle gun shy.
Scoop if it comes to flycutting your current pistons or just buying new ones to clear the 2.02 valve, then I would say stick with teh 1.9s. I say this because the intake runner size stays the same as you bump up to 2.02 from 1.9, so there is only like 5 cfm (according to fordmuscle.com) to be gained on the top end for the 2.02s. 1.9s might make more low end torque too. Just something for you to consider. Paul ------------------
1970 Grande
H code 351W FMX
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Fastymz
Moderator Posts: 13447
From: Reno Nv USA MEM#1240
Registered: Apr 2001
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posted 12-05-2003 04:43 PM
quote:
Originally posted by grandestang:
Scoop if it comes to flycutting your current pistons or just buying new ones to clear the 2.02 valve, then I would say stick with teh 1.9s. I say this because the intake runner size stays the same as you bump up to 2.02 from 1.9, so there is only like 5 cfm (according to fordmuscle.com) to be gained on the top end for the 2.02s. 1.9s might make more low end torque too. Just something for you to consider. Paul
Thanks now I have another choice to make. I'm going with new forged pistons anyways. I might do a stroker too if I can save enough for it.
------------------
SCOOP 2.26 60'S
14.9 @ 90.86MPH 65 coupe,351w,C4,Big Boss 429 hood scoop,8" 3.40 TracLoc. My Pics
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V-8
Gearhead Posts: 198
From: Turkey/Istanbul
Registered: Dec 2003
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posted 12-05-2003 07:39 PM
Fastymz;
what is your comp ratio,intake,ignition,converter?
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Fastymz
Moderator Posts: 13447
From: Reno Nv USA MEM#1240
Registered: Apr 2001
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posted 12-05-2003 07:43 PM
quote:
Originally posted by V-8:
Fastymz;
what is your comp ratio,intake,ignition,converter?
Intake= RPM E-BROCK Comp ratio now is stock about 9.5-1
But should end up after build about 10-1
Duraspark,with MSD blaster 2coil
2400 STALL ------------------
SCOOP 2.26 60'S
14.9 @ 90.86MPH 65 coupe,351w,C4,Big Boss 429 hood scoop,8" 3.40 TracLoc. My Pics
IP: Logged |
V-8
Gearhead Posts: 198
From: Turkey/Istanbul
Registered: Dec 2003
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posted 12-05-2003 09:53 PM
your heads and stall seems good.intake is good for 6500rpm.so you must upgrade cr to 10-10.5 i think.Trick:drop dual plane 1 inc and put a 2500-6500 power band cam.use mech carb.
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