# 455 Rod bolts



## Bensjammin66 (May 12, 2009)

So I know what everyones gonna say already, use ARP..

I have a stout 455 with 6x heads and a .488-.491 cam, stock rods and rod bolts. It did have a fresh rebuild with bearings and forged pistons but those damn weak rods and bolts are in there. I had it rebuilt 10 years ago when I was 17 by a guy who could care less and didnt recommend $80 insurence in new rod bolts.  I was young and didnt know enough to replace them. 

My question is... The highest it will ever see this season is 5200rpm and thats when I go to the track 5 times a year, maybe. I even run an MSD I can limit the rpms with. Will the engine be fine pulling 5000 rpm or am I risking a rod letting go and destroying my getting hard to find 455? The motor has seen high 4s to 5 grand probably 20 times already. 

The thing makes peak power by 5000 anyway so theres no reason to wind them up. I know that for sure. Set the rev limit at 5200 maybe in case i miss a shift? 

I would love to cruise and hot rod this summer without doing rods. Next winter I was planning on doing h-beams and new pistons with KRE heads and all ARP hardware.


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## Eric Animal (Oct 28, 2007)

Technically...you should be OK, BUT......I would go buy ARP bolts.....OR...cruise this summer and stay off the track (better option) and do the motor next winter........


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## Bensjammin66 (May 12, 2009)

Buying arp bolts involves hours removing the engine and completely tearing it down and paying god knows how much in machine work right? At that point its just worth buying h-beams. im ok with a knock if i beat on it then i have to do it, not ok with a broken rod ruining my block though. You think 5 grand is iffy still?


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## 66tempestGT (Nov 28, 2009)

it is still winter here. if they lasted 10 years another summer probably wont make or break you. on the other hand you dont seem comfortable with them and summer is a long way off....


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## Bensjammin66 (May 12, 2009)

i know, and i hate that feeling of will i break it.. I litterally JUST put the tko in too... grrrrrrrrr

Metals Crankshaft.... :shutme


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## jetstang (Nov 5, 2008)

It's a rebuilt motor, what's the worse that could happen?? You're not throwing a bunch of nitrous or a power adder at it.. If you don't spin it too hard, which you don't have to with a Pontiac, the motor should live forever. I've heard of spun bearings, but never throwing a rod unless spun bearing went to far. Spin a bearing, throw a crank kit in with H beam rods, then gtg..


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## Bensjammin66 (May 12, 2009)

Yah I kind of came to my sense's last night. Rev limit pill is set at 5000 and im gonna have fun. If I spin a bearing or hear it knock one day ill get on it. Till then...

What are the tall tale signs of a spun bearing?


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## Eric Animal (Oct 28, 2007)

Knocking and/or loss of oil pressure.......


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## BearGFR (Aug 25, 2008)

Bensjammin66 said:


> My question is... The highest it will ever see this season is 5200rpm and thats when I go to the track 5 times a year, maybe. I even run an MSD I can limit the rpms with. Will the engine be fine pulling 5000 rpm or am I risking a rod letting go and destroying my getting hard to find 455? The motor has seen high 4s to 5 grand probably 20 times already.
> 
> I would love to cruise and hot rod this summer without doing rods. Next winter I was planning on doing h-beams and new pistons with KRE heads and all ARP hardware.


With Pontiacs, whenever there's a failure in the bottom end "most" of the time it's going to be due to a rod letting go. They are the weak link in the chain. Cranks, even the cast ones, are very strong due to their shorter length and the less flex that comes with that. That's the one benefit we get from having the tighter bore spacing and the upper limit that imposes on maximum bore size.
Yes, you'll find people out there who've been able to spin stock rods above 6000 rpm and have never had a problem, but the odds are against it. For every one of those guys, you'll find 10 others with blocks that were trashed when a rod let go sitting in the junk pile in a corner of their garages. Putting better bolts in the factory rods doesn't really address the problem because it's usually not the bolts that fail anyway.

You're already nervous about it and that feeling isn't likely to go away. At 5300 rpm in a stock 455, the forces on the rods and pistons peak at about 2200 G's. Yep, that's two thousand two hundred times the acceleration of gravity. That famous line from the movie, "Dirty Harry", comes to mind... 

"If it were me" I'd curtail stressing the motor until I was able to swap in a set of good forged H-beams and good bolts. There are lots of choices out there these days, but for the price and quality, it's pretty hard to beat the ones from Eagle. 

Bear


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## geeteeohguy (Feb 2, 2008)

I think Bear pretty much summed it up. 455's don't like to rev, and really don't need to to make tons of power. A lot of the folks running them have them peak out at 4800 rpm. The cam, timing, porting, etc. is all tailored for that. That way, the engine lasts forever and is under stressed. Thirty years ago, when I built the 389 that's in my '65 GTO, I re-used the old rod bolts. ARP bolts didn't exist. That engine was balanced and blueprinted, with shotpeened and polished rods (oem rods). That engine has been abused, revved to the moon, and beat on....and is still in the car to this day with no issues. It's a 4 speed car that's run some pretty steep gears in the back. It has 50k miles on it or so. The engine in my '67 is the original 400 I rebuilt in 1988 with the original rod bolts. It too has been revved to the point of lifter pump-up and valve float, but not often. That engine has over 70k on the rebuild with no mechanical issues other than a leaking rear main. Both engines in my GTO's are now treated with much better manners these days due to the value of the cars and my advancing age. I guess what I'm saying is, if you treat your 455 with respect and don't beat it to death, it should be ok. But, like Bear said, if you are worrisome about reliability and want to nail it on the track, you need to upgrade your engine internals to be safe.


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## Bensjammin66 (May 12, 2009)

Well put guys. I think a 5000rpm rev limit pill is going in my 6AL box to prevent disaster until I can afford to do H-Beams. My cam peaks around 5200 so 5k is plenty. Im not scared of 5 grand, its seen it before and will again. But I am concerned for the blocks sake anything over 5. 

With the new TKO I have to kind of do a gentle break in period of about 500 miles anyway. I do want to build my 455 so it can take 6000rpm over and over but that day will come when it comes. Till then I will be as nice to her as possible. Like bear said, if I dont itll end up in the broken parts hall of fame along with u-joints, yokes, axles and everything else thats been destroyed in recent years. 

I can keep my foot out of it im sure, and the rev limit will help but guys.... New TKO600 and 12 bolt 373 posi JUST went in. Im sure you can relate to my concern of my right foot weighing 100 lbs more this season.


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