[West Coast GTO]

I ordered the Eagle forged rods and the machine shop will purchase the forged piston, rings and bearings and balance the assembly.
Here is a fly in the ointment; The 041( SPC-8) cam that is going in is the same one that the engine has been running. I checked lobes today with my digital micrometer and found the old cam with visible wear has higher lobe profiles than the new cam. So do I just put back in the same ( new) cam, purchase a set of Hyland Sharp 1:65 roller rockers or stay with the 1:5's that I have.
Also, the intake( after taking it out of the box from the upper shelf) is a Torker II, not a Performer RPM.

[hurryinhoosier62]

Originally Posted by tom s

The China rods except for maybe Molnar all need to be double checked IMO.Tom

Absolutely, Tom. The ones I'm familiar with are as much as .0015 too tight and have .0075 to .001 taper in them. $400 a set PLUS having a machine shop check and resize them doesn't sound like a very good deal to me.

[hurryinhoosier62]

Originally Posted by FrankieT/A

I guess you're trying to keep the machine shop in business. its very commendable but by the time you pay for all that checking and resizing of inferior and/or outdated parts you might as well buy new stuff.

"5,200 RPM max street 455 with PROPER attention", your quote. Why bother? Why sweat that? JMO

Consider something: NHRA Stock class racers with Pontiacs are still using OE cast steel rods. Only the Super Stock racers get to use Carrillo forged steel rods in their Pontiac engines, as they are the ONLY forged rods allowed by NHRA rules. An old friend of mine (his engines held USAC national sprint car championships) used to say that "new doesn't mean it's any good". How much experience as an engine machinist do you have? My old friend held an FAA Powerplant license as well as USAC certification as an engine builder. I still hold ASE certification as a master engine machinist with both gasoline and diesel endorsements. You can do it "cheap" many times, but it's more cost effective to do it RIGHT once.

[25stevem]

Your totally out of context with the above way of looking at running cast rods in a non race motor!

When used in NHRA competitions your going to go thru the motor and Mag test the cast rods after every race season ( or at least I would !) , and that is as it should be, but in terms of building and running a street motor that makes more power up at a little more rpm then stock red line, you not going to have the luxury of checking the rods again after every 6 months of running now are you?

For a motor build with even a 4.250” stroke, that may spin up to 6800 rpm give me even the cheapest set of 450 buck Forged rods that can be had and I will sleep just fine with no worries at night.

[mgarblik]

The connecting rod debate will never settled. Lets just be glad we have choices we can afford. The OP says he has purchased Eagle rods for his build. My experience has been with Eagle rods, they average about 10-15% of them need to be broken down and rebuilt before they are good enough to run in any engine, street, or race. Are they better quality material than the stock cast rods from 50 years ago? Absolutely. But the out of round, taper, and hole sizes are what will spin a bearing or cause other chaos. If the OP has his machine shop check the new rods and correct them as necessary, they will be better than the stock rods IMO. But it would annoy me as a customer to have to pay a couple hundred bucks to have brand new Chinese rods reconditioned before use. That's the world we live in. When I called Eagle Specialty Products and told them I wanted to buy a small bag of bushings to repair their rods for use, boy did they give me a hard time. When I said my only alternative was to return a couple rods from every set for replacement, they reluctantly sent me a little baggie of bushings. I will say their rods have slowly improved in size and taper the last 15 years.

[FrankieT/A]

Originally Posted by 25stevem

Your totally out of context with the above way of looking at running cast rods in a non race motor!

When used in NHRA competitions your going to go thru the motor and Mag test the cast rods after every race season ( or at least I would !) , and that is as it should be, but in terms of building and running a street motor that makes more power up at a little more rpm then stock red line, you not going to have the luxury of checking the rods again after every 6 months of running now are you?

For a motor build with even a 4.250” stroke, that may spin up to 6800 rpm give me even the cheapest set of 450 buck Forged rods that can be had and I will sleep just fine with no worries at night.

Thank you Steve...

[tom s]

AGAIN!We are talking about a street engine and there we go talking about spinning a 4.25 stroke pontiac to 6800!When I built my 63 421 HO "street" engine I used rebuilt late cast rods for a reason.I lost a engine in a 400 because of dropping a valve and pushed the valve head thru the piston head,bent the "cast" rod some but did not break.I found that they were better than the early forged rods and for my application would be fine.Also has a cast factory arma steel crank,flat tappet 068 cam etc.I think some tend to over build true street engines.I for one am guilty at times!FWIW,Tom

[Mike Davis]

Originally Posted by hurryinhoosier62

Consider something: NHRA Stock class racers with Pontiacs are still using OE cast steel rods. Only the Super Stock racers get to use Carrillo forged steel rods in their Pontiac engines, as they are the ONLY forged rods allowed by NHRA rules. An old friend of mine (his engines held USAC national sprint car championships) used to say that "new doesn't mean it's any good". How much experience as an engine machinist do you have? My old friend held an FAA Powerplant license as well as USAC certification as an engine builder. I still hold ASE certification as a master engine machinist with both gasoline and diesel endorsements. You can do it "cheap" many times, but it's more cost effective to do it RIGHT once.

I think this info is wrong.
Here are the approved rods:

NHRA Accepted Replacement Connecting Rods for Stock or S/S

Effective 12/1/2021
Specs: C/C Length- 6.625" Min Weight- 760g Journal Dia- 2.249" Big End Dia- 2.375" Pin Dia- 0.980"

Manufacturer Part Number C/C Length Wgt. Pin Dia.
Carrillo C427-76635S 6.625" 834g 0.990" Pontiac
Carrillo C427-A76635H 6.625" 787g 0.990" Pontiac **Discontinued**
Carrillo P-455-SS 6.631" 760g NA SUPER STOCK ONLY
Carrillo P-455-SS (2) 6.625" 760g 0.000" Super Stock Only
Childs & Albert 389-12 6.625" NA 0.947" Pontiac
Crower F91059 6.625" NA 0.981" Pontiac
Crower ML93015B5 6.624" 773g NA SUPER STOCK ONLY
Crower SP93419 6.625" 830g 0.947" Pontiac
Eagle CRS-6625P3D 6.625" 760g 0.947" Pontiac
Eagle CRS6635 6.635" 830g 0.990" BB Chev
Manley 14168 6.635" 830g 0.990" BB Chev
Molnar Technologies PH6625WRB8-A 6.623" 769g 0.980"
Oliver ORPPONT6625 6.625" NA 0.981" Pontiac
Oliver P6225PONT 6.625" 790g 0.980" Pontiac
Oliver P6625PONTFR8 6.625" 819g 0.980" Pontiac

[hurryinhoosier62]

Originally Posted by Mike Davis

I think this info is wrong.
Here are the approved rods:

NHRA Accepted Replacement Connecting Rods for Stock or S/S

Effective 12/1/2021
Specs: C/C Length- 6.625" Min Weight- 760g Journal Dia- 2.249" Big End Dia- 2.375" Pin Dia- 0.980"

Manufacturer Part Number C/C Length Wgt. Pin Dia.
Carrillo C427-76635S 6.625" 834g 0.990" Pontiac
Carrillo C427-A76635H 6.625" 787g 0.990" Pontiac **Discontinued**
Carrillo P-455-SS 6.631" 760g NA SUPER STOCK ONLY
Carrillo P-455-SS (2) 6.625" 760g 0.000" Super Stock Only
Childs & Albert 389-12 6.625" NA 0.947" Pontiac
Crower F91059 6.625" NA 0.981" Pontiac
Crower ML93015B5 6.624" 773g NA SUPER STOCK ONLY
Crower SP93419 6.625" 830g 0.947" Pontiac
Eagle CRS-6625P3D 6.625" 760g 0.947" Pontiac
Eagle CRS6635 6.635" 830g 0.990" BB Chev
Manley 14168 6.635" 830g 0.990" BB Chev
Molnar Technologies PH6625WRB8-A 6.623" 769g 0.980"
Oliver ORPPONT6625 6.625" NA 0.981" Pontiac
Oliver P6225PONT 6.625" 790g 0.980" Pontiac
Oliver P6625PONTFR8 6.625" 819g 0.980" Pontiac

Mike, thanks for the update. Been awhile since I read an NHRA rulebook (2008). In any case, OE cast steel rods CAN survive in a STREET ENGINE that will rarely see the high side of 3,500 rpm IF they are properly prepared.

[hurryinhoosier62]

Originally Posted by 25stevem

Your totally out of context with the above way of looking at running cast rods in a non race motor!

When used in NHRA competitions your going to go thru the motor and Mag test the cast rods after every race season ( or at least I would !) , and that is as it should be, but in terms of building and running a street motor that makes more power up at a little more rpm then stock red line, you not going to have the luxury of checking the rods again after every 6 months of running now are you?

For a motor build with even a 4.250” stroke, that may spin up to 6800 rpm give me even the cheapest set of 450 buck Forged rods that can be had and I will sleep just fine with no worries at night.

Really? Based on WHAT factor? I magnaflux ALL OE connecting rods before I use them, period. Doesn't matter whether it's cast or forged. Do you possess x-ray vision? Can you determine whether a rod has reached the end of its cycle life? Do you check both the pin bore and the rod bearing bore BEFORE assembling them into an engine? You have two engine machinists telling you FACTS, but you would rather believe hype, which is your right. I put a lot of stock in Tom S.'s experience in building Pontiacs. The man has built engines most of us have only seen in pictures , let alone own one. If you like supporting the CCP and revel in having to resize NEW connecting rods of dubious metallurgical origin be my guest.

[hurryinhoosier62]

Originally Posted by tom s

AGAIN!We are talking about a street engine and there we go talking about spinning a 4.25 stroke pontiac to 6800!When I built my 63 421 HO "street" engine I used rebuilt late cast rods for a reason.I lost a engine in a 400 because of dropping a valve and pushed the valve head thru the piston head,bent the "cast" rod some but did not break.I found that they were better than the early forged rods and for my application would be fine.Also has a cast factory arma steel crank,flat tappet 068 cam etc.I think some tend to over build true street engines.I for one am guilty at times!FWIW,Tom

Tom, how many conversations have you and I had on this subject over the years? Some of these guys must think a "street engine" has to be built to the same power level as all-out race engines. They do not; what a street engine needs to be built to is to survive in stop and go traffic, be dependable, not overheat, have the ability to pass a gas station and NOT be disassembled on a regular basis.

[tom s]

70 mph on the hiway when let go!

[tom s]

Hard to see in the pics but the rod twisted some and did not break.Engine needed a sleeve and head was a little rough.Rebuilt it with a new piston and rod and and 1 pc valves.Tom

[Mike Davis]

Originally Posted by hurryinhoosier62

Mike, thanks for the update. Been awhile since I read an NHRA rulebook (2008). In any case, OE cast steel rods CAN survive in a STREET ENGINE that will rarely see the high side of 3,500 rpm IF they are properly prepared.

Agree, I used to polish the beams, shot peen them and use the Mopar bolts before the ARP's we available. Lasted through a lot of abuse. Biggest problem with factory rods is the prep.

[FrankieT/A]

Originally Posted by Mike Davis

Agree, I used to polish the beams, shot peen them and use the Mopar bolts before the ARP's we available. Lasted through a lot of abuse. Biggest problem with factory rods is the prep.

Wow, Mike, I remember that. lol I used to polish rod beams and used Mopar rod bolts too... I forgot all about that.

I have been involved in the "Pontiac hobby" for over forty years and one thing stands out when it comes to Pontiac engine failures. "ROD KNOCK".

I have owned over 40 Pontiacs mostly when I was younger, but I have bought plenty of $300.00 GTO's, Firebirds and B bodies with existing rod knocks. Engines fail for a lot of reasons but with Pontiacs 8 times out of 10...its the rods, mostly on the 3/4 journal. Can you get a glass eh I mean cast rod to live? Sure, but its always in the back of your mind.

[70 bird]

Might not be popular opinion around here but the connecting rods is not a real good place to save cash on a rebuild. jmo.

[Tandyman]

This is my bent rod. Car was running 11.70s at the time .Blew a head gasket on a pass.
Started blowing steam out the header on the return road. Studded the block , went .040
over and had another rod polished and beaded . 10 years later switched to eagle h beams.

Glenn

[hurryinhoosier62]

Originally Posted by Mike Davis

Agree, I used to polish the beams, shot peen them and use the Mopar bolts before the ARP's we available. Lasted through a lot of abuse. Biggest problem with factory rods is the prep.

Same here, Mike. I've polished the beams, double shot peened and used SPS bolts ( very high dollar) before ARP bolts and the CCP forgings became available. SD455 rods were made of unobtainium while Carrillo rods were $1,500 at set back in the "bad" old days. I would be more inclined to use Molnar rods or Crower rod in an upper end street engine (especially with power adders). Too many guys cut corners when it comes to rod prep; they also pay the price. The photos Tom posted? If that failure had occurred with a forged rod the rod would have exited through the side of the block. If you are racing a Pontiac, forged rods are your ONLY option.

[FrankieT/A]

I wouldn't classify cast rods as sacrificial. Cast rods don't usually bend much, they are very brittle. Tom's rod as well as Tandyman's was subjected to a compression load, probably the highest type load a cast rod can withstand. Tensile load is a whole 'nother thing. The biggest problem normal street engines face is the big end going out of round.

[tom s]

I dont believe they go out of round!I believe the bolts fatigue and stretch making for a bad ending.JMO,Tom