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Discussion Starter · #1 ·
Hey everyone, I've been having very bad idea's floating around in my head about building this 455 I have, but I keep getting hung up on how strong these rods are. They only have 32,000 km on them since new, so its not like they have had the **** kicked outa them for years. I have been doing a lot of research on building a pontiac, but no one has specified when its actually necessary to replace the rods. I have seen they will give up the ghost at 550hp, but I have also heard they will come apart after 5700 RPM's. Also, I heard it makes a difference in if its forced induction or n/a, is there truth to that? It would make sense to me, but hey, still learning! One more thing, how much of a difference would using some ARP bolts make? I am not actually sure where the weak spot on the rods are, weather its the bolts, or the rod itself comming apart.

Thanks, Adam
 

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Rods

Stock 1963-1979 rods are made of cast nodular iron and are very strong rods up to their elastic limit. I would not hesitate to use them in a high performance street rebuild. The sore spot with those rods are the factory rod bolts and they MUST be replaced with ARP bolts and the big end resized. When the stock bolts stretch, the rod bearing spins out, seizes the rod on the crank pin and breaks the rod and takes the engine with it. ARP bolts and resized rods are a routine procedure with all high performance rebuilds, especially Pontiac rebuilds, because the long stroke Pontiac engines really stress the rods and rod bolts and even more stress with the 455 engines.

I preferred to rebuild EPA friendly 1973-1979 stock Pontiac rods with ARP bolts. In 1973, the EPA forced GM to eliminate the oil "spit-hole" in the camshaft side of the rod cap parting line. The absence of the spit-hole forces more oil across the rod bearing surfaces where it is needed more. The camshaft inPontiac engines gets plenty of oil without the spit-hole because the lifter valley is open. The 455 engines are out of breath above 5500 RPM regardless of what heads are on the engine but that is above the limit for hydraulic lifters anyway. You can use limited travel lifters that set like solids with .003" lash and replace the rocker studs with ARP fully adjustable rocker studs for higher RPM. Comp Cams still offers limited travel (aka short-travel) 1969-1970 RA-IV style Pontiac/Olds hydraulic flat tappet lifters, p/n 863-16. The Comp Cams limited travel hydraulic lifters cannot pump-up and float the valves because they have nowhere to pump-up to. I used the relatively new Comp Cams "short-travel" hydraulic roller lifters in my Chevy 4.3L V6 engine and the RPM is only limited by the strength of the Chevrolet PM rods and ARP bolts. The exact same lifter from GM costs about $50 each!

If successful competiton is your goal with a solid flat tappet or roller cam in a 455 engine, aftermarket steel rods are required.
 

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handymann3 said:
Hey everyone, I've been having very bad idea's floating around in my head about building this 455 I have, but I keep getting hung up on how strong these rods are. They only have 32,000 km on them since new, so its not like they have had the **** kicked outa them for years. I have been doing a lot of research on building a pontiac, but no one has specified when its actually necessary to replace the rods. I have seen they will give up the ghost at 550hp, but I have also heard they will come apart after 5700 RPM's. Also, I heard it makes a difference in if its forced induction or n/a, is there truth to that? It would make sense to me, but hey, still learning! One more thing, how much of a difference would using some ARP bolts make? I am not actually sure where the weak spot on the rods are, weather its the bolts, or the rod itself comming apart.

Thanks, Adam
In my opinion the stock rods would be OK for a stock or very mild build. If you are on a tight budget...OK.

Staying at or below 5250 on a 455 is a good idea.
However if you are gonna build your motor with some quench it would be good piece of mind to use forged rods.
Butler performance has RPM rods, forged, with larger than stock bolts allready in them for 240 bucks. It doent pay to even foolwith the stock rods at this point. Till you resize both ends and fit them with arp hardware, forget it. I got a set,they are allready weighed and come with a weigh sheet for each one.( my machinist will measure em again)
I put forged pistons in my build too.
Forged for that price is very inexspensive peace of mind.
 

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Discussion Starter · #4 ·
Thanks for the replys. So would the stock rods the way they are hold 450ish hp and quick blasts to 5500 RPMS? I wanna have her on the road in the next few months and was thinking i would tear into her next winter, or build a stroker 400. I have been looking at rods and I see the 5140's, and for another $120 or so i could get 4340's. Whats the difference in strength between the two?
 

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Stock rods

Stock Pontiac rods should never be used unless they are reconditioned with ARP rod bolts. However, stock Pontiac rods thatare reconditioed with ARP bolts will be fine in a daily driver with "occasional" bursts of speed up to 5500 RPM. If you still have your freeway flyer rear end gears, don't worry about high RPM rod failure.

Constant thrashing at the drag strip requires aftermarket I-beam steel rods and forged pistons or engine failure is guaranteed.
 

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handymann3 said:
Thanks for the replys. So would the stock rods the way they are hold 450ish hp and quick blasts to 5500 RPMS?
No. Youd better get some forged rods.5250 rpm is red line for the 455 CI with a stock rod.I am certain it is higher after putting ARP fasteners but like i said , wich has been preached to me by well known pontiac gurus,untill you spend the money for ARP then get the rods sized you are almost at the price of the less exspensive forged rod at butler.Why spend the money on the stock stuff when the upgrade is only a few extra bucks.
 

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handymann3 said:
Thanks for the replys. So would the stock rods the way they are hold 450ish hp and quick blasts to 5500 RPMS? I wanna have her on the road in the next few months and was thinking i would tear into her next winter, or build a stroker 400. I have been looking at rods and I see the 5140's, and for another $120 or so i could get 4340's. Whats the difference in strength between the two?
It's not hard at all to build a mid 12 second 455 that shifts at 5000 RPM, using no more rear gear than 3.23/3.31 (10- and 12-bolt ratios, respectively), in a 3600 lb. vehicle. Stock cast rods are OK at this level (450 HP)- as long as they've had ARP bolts installed along w/resizing. But it's just not necessary- and will slow your quarter mile ET- to turn the 455 to 5500 RPM, if mid 12's are your goal.

If you're camming for a shift point much higher than that, you're going to need ported Pontiac heads or aftermarket heads anyway. At that stage, forged rods are a no brainer.

ANY forged rod that's made by a reputable manufacturer will be better than a cast iron rod. Use the same guidelines for material as you would for any engine. Obviously 4340 steel has more strength than lesser alloys. Whether or not you need the extra strength depends on the RPM/output you're building the engine to.
 

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cobalt327 said:
ANY forged rod that's made by a reputable manufacturer will be better than a cast iron rod.
With the exception of the '58-'62 Pontiac "rubber" rods. The Super Duty rods were good rods, but the production rods were not.

Bill
 

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WDCreech said:
With the exception of the '58-'62 Pontiac "rubber" rods. The Super Duty rods were good rods, but the production rods were not.

Bill
LOL I guess Pontiac OEM forged rods could fall under the heading of a "reputable manufacturer", but I was really speaking about aftermarket rods.
 

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cobalt327 said:
LOL I guess Pontiac OEM forged rods could fall under the heading of a "reputable manufacturer", but I was really speaking about aftermarket rods.
I knew what you meant, but thought it should be clarified for those that aren't that familiar with Pontiacs.
 

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FWIW when I was a young sprout I had a '67 GTO with a 335HP 400, "YS" Code IIRC. I rebuilt the original 400 with TRW forged pistons and had ARP rod bolts installed in the stock rods and the rods resized. I had a fairly healthy Cam Dynamics cam and a Torker intake, TH400 and 3.55 posi. I ran it hard and put it away wet for over 33,000 miles. It saw 6,000 RPM on nearly an hourly basis. I'd race anybody and anything at the drop of a hat even if I knew I'd get creamed. When the body finally rusted away the engine was still going strong.

Fortunately for all of us I outgrew that phase without hurting anyone. If I were to meet myself at that age now I'd probably slap the "young me" into next week. :embarrass :spank:
 

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Discussion Starter · #12 ·
Thanks everyone, I was just wondering that there limits where. I wouldn't bother with resizing and fitting them with ARP's at the cost of the forged ones. I knew stock rods where weak, but man that's WEAK! I don't plan on twisting the 455, there really isn't much point since it makes a lot of grunt down low. Its just the pain in the *** to have to pull the engine and separate it from the tranny, ect... But if you gotta do it you gotta do it! I was just wondering the difference in rod strength because I think I will just experiment with this engine. I wanna try different combinations and see how fast I can go on the cheap. Just a sort of learning experience :p I just want a strong base to start with so I guess those rods are comming out as soon as I can.
 

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big cube poncho motors are getting kinda scarce at the salvage yards.It isnt worth the bucks to chance a stock rod exiting through the side of the block.
The few extra bucks spent on forged rods is good piece of mind. :thumbup:
 

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handymann3 said:
Thanks everyone, I was just wondering that there limits where. I wouldn't bother with resizing and fitting them with ARP's at the cost of the forged ones. I knew stock rods where weak, but man that's WEAK! I don't plan on twisting the 455, there really isn't much point since it makes a lot of grunt down low. Its just the pain in the *** to have to pull the engine and separate it from the tranny, ect... But if you gotta do it you gotta do it! I was just wondering the difference in rod strength because I think I will just experiment with this engine. I wanna try different combinations and see how fast I can go on the cheap. Just a sort of learning experience :p I just want a strong base to start with so I guess those rods are comming out as soon as I can.
Pontiac rods are already pretty long, at 6.625", and you wouldn't want to change thier length unless you were building an all out race engine with a stroker kit, as you would need special pistons to go with the rods.
 

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When I hear "cheap", "fast" and "Pontiac" all in one breath, I always say you can have two of the three, no problem!

You'll find that besides the cast rods, the bottleneck is the cylinder heads. If you want to make big power- like over 500 HP or so- aftermarket heads are the best way to go, short of rare and expensive OEM round port iron Pontiac heads. Unless you're very good at porting, there's no way to get around this.

This is the area where you'd want the 3" mains like a 400 block has. 4-bolt blocks are rare, so aftermarket 4-bolt caps can be used when needed. Roller cams can crack the lifter bores, there are "fixes" for this available.

Try to work w/a FT piston. Domed and dished pistons are more than FT's, generally speaking.

No need to reinvent the wheel on your quest for affordable Pontiac power, following are some links to get you started:

SOME SITES FOR PONTIAC PARTS & INFO:

Ken “Ace” Brewer @ Pacific Performance Racing- http://www.pacificperformanceracing.com/index.html

Butler Performance- http://www.jbp-pontiac.com/

SD Performance- http://www.sdperformance.com/

Performance Years Pontiac (One of the largest sites)- http://www.performanceyears.com/

Ken’s Speed & Machine Shop- http://www.angelfire.com/fl4/pontiacdude428/kensspeedandmachineshop.html

Nunzi- http://www.nunzi-pontiac-expert.com/

Fulper* aka Rock & Roll Engineering- http://pontiacpower.com/
*One of the Pontiac guys here has warned about this guy. I have had no dealings w/him personally, so have no comment either way, except to say his claims and rhetoric is definitely "over the top".

SD Performance- http://www.sdperformance.com/

Tin Indian Performance http://www.tinindianperformance.com/

Kauffman Racing Equipment- http://www.krepower.com/

All Pontiac.com- http://www.allpontiac.com/

Wallace Racing- http://www.wallaceracing.com/


A FEW SELECTED ARTICLES BY JIM HAND (there are many more)

Jim Hand “BUILDING A STRONG STREET MACHINE”@ Classic Firebird
http://www.classicfirebird.com/hand/hand.html

Hand on Cams
http://www.dapa.org/jhpages/pontiac-cams.htm’

Hand on ROCKER RATIOS/MODS
http://www.pontiacstreetperformance.com/psp/RockerArms.html


PONTIAC MAGS ON THE WEB:

Pontiac Street Performance
http://www.pontiacstreetperformance.com/

Pontiac Street Performance Featured Cars & Engines
http://www.pontiacstreetperformance.com/psp/featuredcars.html

Pontiac Street Performance Tech Articles
http://www.pontiacstreetperformance.com/psp/techarticles.html

High Performance Pontiac
http://www.highperformancepontiac.com/

Also, there have been numerous threads here- hit "Search" for more info.
 

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i wanted cheap pontiac power to then 1 thing after another and poof their wenk 7k crank rods pistons and heads ate 5 up then the other 2 on small odds and ends intake cam carb general bs like that
 

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Discussion Starter · #17 ·
By cheap and fast I meant just using iron heads. I wanted to see how fast you can go on the least amount of money. I wanted to try my hand at porting on some 6x-8 heads I could pick up for cheap, try using a turbo of a diesel with my stock 6H heads, play around with making custom turbo headers, just try anything I can think of and see how fast I can go. Sure you could look up tried and true engine combo's, but I think this would be both more fun and a great learning experience. I am absolutely fascinated with Pontiac and oldsmobile and I want to learn as much as I can from both research and just seeing what I can do from trial and error. I have Jim hand's book as well as I have found some articles online from him, but the one thing I wasn't able to find was just how weak the rods where. But when you guys told me how weak they where I just couldn't believe it. Why would they make a rod that weak? I just don't understand :s I am very interested in reading that link from Jim Hand on building a strong street performer, but the link doesn't seem to work. Maybe its just me? By the way, what are these "fixes" for the lifter bore? Just a brace? I am very interested in these limited travel lifters, I think I will look into them. Thanks for all the info so far everyone!
 

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Stay right the hell away from Bruce Fulper and Rock and Roll Engineering...period! The engine in the Tempest in my album is 550HP/570TQ. I built it for the Street, but it turns 11 teens at the Strip. Butler rods, Edelbrock heads, Wentzler intake, and it's NOT built to run RPMS like a Chevy. That's what transmissions are for. 5,500 RPM...grab another gear. Oh, and BTW, it wasn't "cheap"... :thumbup:
 

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handymann3 said:
...when you guys told me how weak they where I just couldn't believe it. Why would they make a rod that weak? I just don't understand...
While the cast rods can be a weak link from a high performance standpoint, you have to remember the Pontiac engine was designed from the beginning as a low RPM engine, with the torque to get a two-ton vehicle moving briskly. In that sense, the rods are as robust as is needed. It is RPM that 'kills' rods and the hardware- not low RPM torque.

You never hear of an OEM Pontiac engine having rod problems (at least no more so than any other brand) until the engines are really leaned on. I will even say that the cast iron Pontiac rods- if inspected, equipped w/ARP hardware and sized- will handle anything an engine built w/a set of mildly ported D-port iron heads and a hydraulic cam can dish out!

It's when elevated RPM is needed to reach the power peak that forged rods come into their own. This usually means aftermarket heads and enough cam to need a solid FT or roller valve train- the SAME area where a Chevy engine would be looking to aftermarket rods, too. ;)
 

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Discussion Starter · #20 ·
I will be replacing the stock rods with a set of forged ones for sure now. Just outta curiosity though, how often are rods so out of round that they need to be resized? Could that even be the case with something as little as 32,000 km such as in my case?
 
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