connecting rod decision

[robert leazenby]

I am building a spare motor for my 70, LT-1. Obviously I want the engine to rung strong and am building to LT-1 specs with a few little improvements. Roller tip rockers, stainless valves, new generation guide seals etc.

Other than running strong, I want it to be reliable and be drivable. I am the point where I need to decide on connecting rods. My donor motor (3970010 cast) had forged rods in place. Not pink rods but forged none the less. I am considering installing Crower forged rods (4340 steel) There is a substantial increase in cost over having the donor rods re-sized so I need to determine if it is worth the cost for the Crowers or should I just use the stock forgings.

[Clem Z.]

Re: connecting rod decision

get them maged,install new bolts and reconditioned and you will be good for years. we ran stock chevy rods for years in race cars turning 7000+ rpms with no failures.the bolts are always the problem not the rods even in aftermarket rods.

[Clem Z.]

Re: connecting rod decision

get them maged,install new bolts and reconditioned and you will be good for years. we ran stock chevy rods for years in race cars turning 7000+ rpms with no failures.the bolts are always the problem not the rods even in aftermarket rods.

[Joe L.]

Re: connecting rod decision

Robert and Clem-----

Yes, all Chevy 350 small block rods are 4340 forged steel (except very late build ones after about 1994 which use forged powder metal). The primary difference between the "pink" inspection mark rods (originally GM #3973386 and later GM #14095071 and 14096846) is surface preparation including shotpeening, stress relief, and magnaflux inspection. All of those can be done on an existing set of standard 350 rods thereby converting them to "pink" status.

For rod bolts, I recommend using ARP Wave-Lok rod bolts of their "Professional Series". These bolts have a tensile strength of 220,000 PSI and, due to their design, are virtually fracture-proof. They're not outrageously expensive, either.

A set of standard 350 rods, suitably prepped and fitted with ARP rod bolts, are as good, and probably better, than "pink" rods.

[Joe L.]

Re: connecting rod decision

Robert and Clem-----

Yes, all Chevy 350 small block rods are 4340 forged steel (except very late build ones after about 1994 which use forged powder metal). The primary difference between the "pink" inspection mark rods (originally GM #3973386 and later GM #14095071 and 14096846) is surface preparation including shotpeening, stress relief, and magnaflux inspection. All of those can be done on an existing set of standard 350 rods thereby converting them to "pink" status.

For rod bolts, I recommend using ARP Wave-Lok rod bolts of their "Professional Series". These bolts have a tensile strength of 220,000 PSI and, due to their design, are virtually fracture-proof. They're not outrageously expensive, either.

A set of standard 350 rods, suitably prepped and fitted with ARP rod bolts, are as good, and probably better, than "pink" rods.

[Dale Pearman]

Re: connecting rod decision

Joe's right. (so's Clem). Stock rods, when prepped correctly and fitted with good bolts torqued with a micrometer for stretch will be as good as any aftermarket pieces.

Dale.

[Dale Pearman]

Re: connecting rod decision

Joe's right. (so's Clem). Stock rods, when prepped correctly and fitted with good bolts torqued with a micrometer for stretch will be as good as any aftermarket pieces.

Dale.

[Wally Knight]

Re: connecting rod decision

Let's see, a set of stock rods, with all the work done on them or a set of good Crower or Eagle rods.

Stock rods need to be cleaned, shot blasted, ARP bolts installed and then the big end resized. If there are pistons on them you pay to remove those.

Bolts from the mail order *****s cost what, 50 to 60, the machine shop should charge 20 bucks to remove pistons, cleaning, maging and shot peen. Then the labor for installing the bolts and resizing. Your over 200 already and at the end of the day you still have a stock set of rods that are how old? For 229 you can have new Eagle rods, made like the stock rods. For 479 the H-beam rod.

[Wally Knight]

Re: connecting rod decision

Let's see, a set of stock rods, with all the work done on them or a set of good Crower or Eagle rods.

Stock rods need to be cleaned, shot blasted, ARP bolts installed and then the big end resized. If there are pistons on them you pay to remove those.

Bolts from the mail order *****s cost what, 50 to 60, the machine shop should charge 20 bucks to remove pistons, cleaning, maging and shot peen. Then the labor for installing the bolts and resizing. Your over 200 already and at the end of the day you still have a stock set of rods that are how old? For 229 you can have new Eagle rods, made like the stock rods. For 479 the H-beam rod.

[Clem Z.]

Re: connecting rod decision

do not forget to rebalance if you go for aftermarket rods.

[Clem Z.]

Re: connecting rod decision

do not forget to rebalance if you go for aftermarket rods.

[Duke W.]

Re: connecting rod decision

The stock rods are okay, but they should be magnafluxed, new (higher quality) bolts installed, resized, and balanced. You might also want to rework the I-beam section IAW the Chevy Power Manual for peak reliability and re-shot peen them. The trouble is, the cost of all this would probably about equal the cost of a new set of Crower Sportsman rods. They are sold in matched weight sets and are ready to go. You balancer shop will just need one to determine the end weights to get the crank balanced.

I think the Crower Sportsmans are the best buy. I haven't looked at the Eagles lately, but I think they are a bit heavier. My understanding is that the Eagles are forged in China or somewhere in SE Asia and finished machined here. The Crowers are forged in the USA as far as I know.

IMO roller rocker tips are a waste of money. Those funds are better spend working on the heads and doing a three angle valve job.

With the Crower rods, a magnafluxed and straight crank, and proper bearing clearances, the bottom end should be indestructable as long as the bearings never get oil-starved.

Duke

[Duke W.]

Re: connecting rod decision

The stock rods are okay, but they should be magnafluxed, new (higher quality) bolts installed, resized, and balanced. You might also want to rework the I-beam section IAW the Chevy Power Manual for peak reliability and re-shot peen them. The trouble is, the cost of all this would probably about equal the cost of a new set of Crower Sportsman rods. They are sold in matched weight sets and are ready to go. You balancer shop will just need one to determine the end weights to get the crank balanced.

I think the Crower Sportsmans are the best buy. I haven't looked at the Eagles lately, but I think they are a bit heavier. My understanding is that the Eagles are forged in China or somewhere in SE Asia and finished machined here. The Crowers are forged in the USA as far as I know.

IMO roller rocker tips are a waste of money. Those funds are better spend working on the heads and doing a three angle valve job.

With the Crower rods, a magnafluxed and straight crank, and proper bearing clearances, the bottom end should be indestructable as long as the bearings never get oil-starved.

Duke

[Joe L.]

Re: connecting rod decision

Duke-----

Crower Sportsman connecting rods are, in my opinion, the best value in aftermarket connecting rods and are fully US-manufactured. For a small block, they cost about $550 per set. Stock rods can be fully prepped and fitted with ARP rod bolts for about half that, so there is a significant difference in price.

Personally, I would not touch any of the foreign-sourced, lower priced rods with a 10 foot pole.

[Joe L.]

Re: connecting rod decision

Duke-----

Crower Sportsman connecting rods are, in my opinion, the best value in aftermarket connecting rods and are fully US-manufactured. For a small block, they cost about $550 per set. Stock rods can be fully prepped and fitted with ARP rod bolts for about half that, so there is a significant difference in price.

Personally, I would not touch any of the foreign-sourced, lower priced rods with a 10 foot pole.