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Discussion Starter · #1 ·
How high are you guys with 302 or 5.0 "stock bottom end" spinning your motor to? I mean on a regular basis like weekends at the track even with heads and cam mods and not blowing it up. Anyone know somebody brave enough to wind it up to 7000 grand or higher week after week?
Just asking cause them little 5/16 rod bolts dont look like they can take it. Some guys believe they can.
 

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I'll let "some guys" do that. In class racing, we would spin to over 7000, but we all used replacement rod bolts. Oops - I mean... some guys would. ;) In-fact, the first thing everyone will tell you if you're doing a mild upgrade to the stock stuff is to change to high-strength rod bolts and get your dimensions right. Since you don't know who assembled, or to what torque, or what revs it's seen since new, or how well it was balanced, or what the big-end stretch is, or what the current bearing clearances are (all factors in rod bolts staying together), nobody can say what it will take today - right now. I keep unknown stock 302/5.0L bottoms (they all have the same C8 rods up into the'90s) in the low 6000s at most. Some have minimally spun bearings at less than that, so...

David
 

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I used ARP bolts with the older stronger 302 rods with a 275 shot of nitrous for years with no problems. She would be well over 7500 rpms in a heart beat.

PS, that's with Vic Jr heads.
 

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My solid roller cammed 289 was specd out to be able to spin up there.

At minumim my builder wanted ARP rod bolts if not new rods. But at that point I decided to get a stroker kit.

It has seen well into the 6500 range several times and it gets there FAST!

Too much fun!
 

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Then of course, its a matter of having the right combo to make it even worthwhile spinning her to 7K,
I know my little 5.0 has strong enough bottom end to spin to 7 but,according to my dyno read outs, its made all the power its going to by 6500rpm.
From what i;ve seen, which isn;t much compared to allot of the guys on here, a stock bottom end 5.0 is living on borrowed time, reving to 7K for any length of time
 

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I "touch" 7 G's with my stock bottom 289, but constantly rev it to 6200 on a regular basis. Thats with stock rod bolts.:eek:
Been doing that for 5 years now.
 

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Discussion Starter · #8 ·
I really liked to hear how each of you guys reved your babies out. Seems like 6000-6200 is about it for a stock bottom. 7 k is do able with arp rod bolts. Good to hear that those rods can be upgraded for cheap. Kinda hard to image those 5/16 bolts can hold on compared to other rods with 3/8 or 7/16 bolts and theyre rated at 7k.
Anyone else out there winding her up???
 

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my 2 cents, had a high rev 289 street/strip for 10 years with no problems. 1968 mustang, torker intake, set of hooker heads, 650 holley double pump, wide ratio top loader, 5.14 9 inch, hays clutch, stock 1967 block and rods, rods were polished and shot peened, arp bolts, windage tray in oil pan, stock crank, melling high pressure oil pump, cloyes double roller chain, 1969 351w heads 1.94 1.60 ss valves screw in studs and guide plates, cheep aluminum rockers, comp solid flat tappet cam 306D .592 LIFT, TRW 12.5 pop up forged pistons. with the 351 heads 65cc chamber it ran fine on 93 octane with 36 total timing. shifted at 7400 launched it at 6700. only ran 12.80 but was a hell of alot of fun. HOPE THIS HELPS.
 

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With the replacement of the bolts with ARP's and other proper prep 7k isnt unobtainable as a red line. (or a smidge more, 7-7200) MO, of course.
 

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all about the balance... some factory stuff by chance is right on... always a good place to spend money though... nasty harmonics are squared with rpm ... a 1/4 ounce of imbalance 4 inches from crank centerline weighs 63 lbs !! at 6000 rpm but 112 lbs at 8000 rpm!!... we had a circle track stock rod chevy we raced at 6800 for two years then switched the gears and turned it to 7000 one time... boom... just sayin
 

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all about the balance... some factory stuff by chance is right on... always a good place to spend money though... nasty harmonics are squared with rpm ... a 1/4 ounce of imbalance 4 inches from crank centerline weighs 63 lbs !! at 6000 rpm but 112 lbs at 8000 rpm!!... we had a circle track stock rod chevy we raced at 6800 for two years then switched the gears and turned it to 7000 one time... boom... just sayin
Imbalance and harmonics can be damaging, but this is not what will break rods, and especially rod bolts. The G forces seen as the piston abruptly changes direction at TDC can be several thousand as RPM climbs. As stroke increases, the G forces increase since piston speed increases. A 1 lb piston exerts force of several thousand lbs on the rod in tension. The 289 and 302 have short stroke so they are easier to build for 7000+ rpm. Dont try it with a 428 without a lot of upgrades.
 

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Imbalance and harmonics can be damaging, but this is not what will break rods, and especially rod bolts. The G forces seen as the piston abruptly changes direction at TDC can be several thousand as RPM climbs. As stroke increases, the G forces increase since piston speed increases. A 1 lb piston exerts force of several thousand lbs on the rod in tension. The 289 and 302 have short stroke so they are easier to build for 7000+ rpm. Dont try it with a 428 without a lot of upgrades.

yes... not saying balance fixes everything... sure helps though... point was that last 200 rpms could be the killer... piston g,s included... with short rod motors the piston also has a shorter dwell time at tdc which adds to abrupt loads... thats why we build light piston balanced motors to go 7 grand
 

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I had an HO 302 out of a 1990 Mustang, rebuilt with ARP rod bolts, balanced and blueprinted. I revved her from 6800 to 7500 rpm regularly. The engine was in my road race/drag race/autocross Mustang. She saw a LOT of action back in the early 90's and the engine lived through it all. I even drove the car from NYC to Monterey, CA where I raced her for another year (3 years in total). This car/engine was also my daily driver at the time. :)




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I'm running stock rods and crank in a 289 over 7000. ARP rod bolts and a high speed performance balance. The crank and rods were double shot peened and stress relieved and the crank oil holes are chamfered. Just basic stuff.
 
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