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Author
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Topic: Original flat-top pistons, what can they handle?
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Swederoos
Journeyman Posts: 3
From: Sweden
Registered: Aug 2005
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posted 08-04-2005 09:16 AM
 
Hi! Wonder what punishment a original 1970 351 Cleveland 4v crank,stock piston, flat-top and rod can handle.New bearings, rings and etc. Rpm, comp and hp? Roughest cam? Thanks,
Swederoos
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"Live like you are dying"
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68 Coop
Gearhead Posts: 5847
From: Mesquite, NV. 89027
Registered: Oct 2004
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posted 08-05-2005 12:29 AM
Welcome to mustangsandmore. Are you talking about boring it out any, or staying stock??? I would think a 270 or 280 would be the biggest cam you would want to go, but I'm only going from memory of posts I've seen on the subject. I hope some 351 owners will jump in with some better recommendations, just takes a few minutes sometimes.------------------
William
68 Coupe
289
Edelbrock 600
Performer Intake
Headers/X-pipe/Flowmaster 30's
C4
8"rear/2:79gears
"Restomod in Progress" Good friends are hard to find, even harder to leave, and impossible to forget.
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Swederoos
Journeyman Posts: 3
From: Sweden
Registered: Aug 2005
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posted 08-05-2005 03:52 AM
Hi William,Thanks for your answer. I know that in the old days (`60s)the were using cast pistons in competion as SCCA and rev them to 7,000 rpm. I will try to keep it stock as long as I can but still would like some more power. Alot modified stuff already, MSD all the way, headers, 3:70 gear etc. What about this cam, itīs a custom grind. Comp Cams, Hydr Roller
Grind # FC 3613/3355 HR110+4
@ .006 = 282/290
@ .050 = 230/236
Lift w/1.7 = .544/.547
110 lobe sep with 4 adv.
@ .050 open / close
intake 9 41
exh 52 4 Thanks
Roos
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68 Coop
Gearhead Posts: 5847
From: Mesquite, NV. 89027
Registered: Oct 2004
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posted 08-05-2005 07:42 AM
Well Roos, like I said, I am GREEN when it comes to a lot of this stuff, but it sounds like it would be a ROCKER! I will say with some confidence, that you do have one of the best years for the 351, as far as the cast and strength. Sorry Bro, wish I could be of more help, but it's back on top, so let's see what happens now  . ------------------
William
68 Coupe
289
Edelbrock 600
Performer Intake
Headers/X-pipe/Flowmaster 30's
C4
8"rear/2:79gears
"Restomod in Progress" Good friends are hard to find, even harder to leave, and impossible to forget.
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SteveLaRiviere
Administrator Posts: 48752
From: Saco, Maine
Registered: May 99
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posted 08-05-2005 08:53 AM
A lot of it depends on how well you can ward off detonation, that's the real killer with cast pistons. If you can keep the detonation under control and your side clearances are what they should be, you should be good for up to 6000 rpm. For compression, they were used to provide 10.7:1 with the '70 4V closed chamber head, so there a vote of confidence from Ford. How rough a cam probably doesn't make a difference as long as you have the proper valve to piston clearance.Welcome to M&M. ------------------
'70 Mustang Mach 1 351C 4V/FMX/3.25 Open
'70 Mustang Convertible 250 I6/3 speed/2.79 Open
'72 Mustang Sprint Hardtop 351C 4V/FMX/4.30 Trac Loc
'94 F-150 XL 5.8L/E4OD/3.55 Limited Slip
'05 Mercury Sable LS 3.0L DOHC 24V Duratech V6
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SteveLaRiviere
Administrator Posts: 48752
From: Saco, Maine
Registered: May 99
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posted 08-05-2005 09:03 AM
I should add, though, with the engines I've built I've always felt the cost of forged pistons was always worth it, especially when I ran into a couple of valve failures. I like using the TRW/Sealed Power L2379F forged flattops.------------------
'70 Mustang Mach 1 351C 4V/FMX/3.25 Open
'70 Mustang Convertible 250 I6/3 speed/2.79 Open
'72 Mustang Sprint Hardtop 351C 4V/FMX/4.30 Trac Loc
'94 F-150 XL 5.8L/E4OD/3.55 Limited Slip
'05 Mercury Sable LS 3.0L DOHC 24V Duratech V6
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n2oMike
Gearhead Posts: 3058
From: Spencer, WV
Registered: Jan 2001
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posted 08-05-2005 09:42 AM
It's not the pistons you've got to worry about on a Cleveland.... it's the heads!They came with the worst valves known to man... held very loosely with the 'ill fated' multi groove retainers that hold the valve loosely to promote valve rotation. (this was supposed to promote more even wear) Anyway, the heads have a tendency of breaking off the valve stems. This happens a LOT. The valves NEED to be replaces on ANY 351C build. Replace them with a decent set of stainless valves and single groove locks and retainers. Take care of this, THEN worry about the pistons. Good Luck! ------------------
Mike Burch
66 mustang real street
302 4-speed 289 heads
10.63 @ 129.3
http://www.geocities.com/carbedstangs/cmml_mburch.html
http://www.fortunecity.com/silverstone/healey/367
http://www.mustangworks.com/cgi-bin/moi-display.cgi?220
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Swederoos
Journeyman Posts: 3
From: Sweden
Registered: Aug 2005
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posted 08-08-2005 09:39 AM
Come across this http://www.mustangsandmore.com/ubb/SteveWmaxpistonspeed.html Guess 6000 rpm is the limit for a stock 351! /Swederoos
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