[West Coast GTO]

Well, job creep went from replacing my cam and carburetor to pulling the 455 , disassembling and sending to machine shop. They will clean, deck, bore to 30 over,align hone , resize crank( 2 bolt) and balance, recondition rods, new cam bearings, new pistons, rings and bearings in about a month.
So here is my question. Since I want to keep the cost manageable and don't need to create a high horsepower/ high torque monster, should I pay more for forged rather than cast pistons? Also, since it is a 2 bolt main, should I keep the original mains or go with the 4 bolt main center caps? In addition, the torque converter in the car is a 2200 stall unit. Is that sufficient for this size engine?
The rest of the engine will stay with:
Edelbrock round port heads
Edelbrock Performer or RPM intake( I have both)
Newly rebuilt Cliff Quadrajet
041 cam
Scorpion 1.5 rockers
RAIV high flow factory type headers

Thanks for any suggestions

[b-man]

Forged pistons for sure.

Keep the 2-bolt mains, they’re fine for up to 600 hp.

I wouldn’t spend money reconditioning stock cast rods, there’s plenty of affordable new forged rods out there. This is money well spent, spend it here rather than on converting the bottom end to four bolt caps.

[62posbonny]

Same opinion as above. Keep 2 bolt mains, get inexpensive forged rods and forged pistons, and upgrade to 1.65 rockers for a really good understressed street combination that will last a long time. Depending on weight and gearing 2200rpm stall might be too low.

[SD455DJ]

X2 to what B-man & 62posbonny are saying, plus go with the Performer RPM intake with those alum. heads.

Dennis

[tom s]

Since your going to get custom pistons ASK if it REALLY needs to go 30 over or will 10-15 clean it up!So many times shops just go the EZ route and go 30-60 etc.Tom

[West Coast GTO]

I saw the head machinist check the bores when I dropped off the block. I was hoping for a simple hone but nope. Also, when disassembling the engine, there were quite a few stupid mistakes made by whoever worked on the engine last.

Originally Posted by tom s

Since your going to get custom pistons ASK if it REALLY needs to go 30 over or will 10-15 clean it up!So many times shops just go the EZ route and go 30-60 etc.Tom

[tom s]

I just dont like boring a 455 block anymore than actually needed!History shows they are thin blocks.Tom

[West Coast GTO]

The ridge was .010 difference to the main bores with slight measurable variations( taper) between each cylinder. Each cylinder wall was glassy/ polished with no discernible cross hatch pattern( on an engine that was supposedly rebuilt 300 miles before I bought the car. The heads and piston tops showed a build up of carbon and oil. The cast pistons had slight scuffing at skirt areas and ,025 gap at top ring. The aluminum heads had to be removed with a 1/2" breaker bar with a 3' tube extension( I would guess over 200 ft/lbs but my torque wrench only goes up to 150) and I actually broke/ cracked two short 9/16 sockets. Between the debris and loose pieces of blue RTV sealant, it was a wonder there was any oil pressure. Surprisingly, the crank spun as smooth as silk with the pistons/ rods removed.
I have rebuilt Chevy small and big block engines with .030 and .060 overbores but this is my first Pontiac rebuild. I want to get it right.

[mgarblik]

There are probably 100 different definitions for what a "rebuilt, remanufactured, or refurbished" engine is. I can't imagine any scenario that would indicate any of those words could be used in a legal sense on that engine. Just from 2 pictures, I see nothing that indicates the engine had any lower end attention. It takes tens of thousands of miles to create a ring ridge and create a wall glaze like that. Even if it was just ball honed, the hone pattern would be there at 300 miles. Anyway back to your question. I don't see any reason for 4-bolt caps from the built you describe. I will however break with the other posts indicating you need new connecting rods. IMO, it depends on the quality of the machine shop. A 455, running at 5200 RPM or less, won't hurt stock connecting rods that are round, straight and the right size with new hardware. Cheap, Chinese aftermarket rods, however will certainly need to be carefully measured, inspected and 1 or 2 will probably have to be rebuilt prior to use. So it's kind of a toss up IMO concerning the rods. Good luck with it.

[West Coast GTO]

I agree with your evaluation on the ring ridge and glaze as well as any "rebuilt" lower end condition. Since it is apart, I now want a strong, dependable engine al the lowest cost. It appears to be a consensus that the 2 bolt bottom end is good for my needs so I will upgrade to forged pistons and rods and have the machinist check bore tolerances again before he over bores
. Thank you to all that have posted here, I really appreciate it.

Originally Posted by mgarblik

There are probably 100 different definitions for what a "rebuilt, remanufactured, or refurbished" engine is. I can't imagine any scenario that would indicate any of those words could be used in a legal sense on that engine. Just from 2 pictures, I see nothing that indicates the engine had any lower end attention. It takes tens of thousands of miles to create a ring ridge and create a wall glaze like that. Even if it was just ball honed, the hone pattern would be there at 300 miles. Anyway back to your question. I don't see any reason for 4-bolt caps from the built you describe. I will however break with the other posts indicating you need new connecting rods. IMO, it depends on the quality of the machine shop. A 455, running at 5200 RPM or less, won't hurt stock connecting rods that are round, straight and the right size with new hardware. Cheap, Chinese aftermarket rods, however will certainly need to be carefully measured, inspected and 1 or 2 will probably have to be rebuilt prior to use. So it's kind of a toss up IMO concerning the rods. Good luck with it.

[70KGOLD]

Use ARP bolts throughout the engine. You will be fine.

[tom s]

JMO,no reason to change bolts on that engine.Tom

[blueghoast]

Originally Posted by tom s

JMO,no reason to change bolts on that engine.Tom

True that.
That will be a bad ass motor with the round port allum-heads and a RAIV
cam. You are gona love it and it will be super street friendly.

GT

[FrankieT/A]

On another note I wouldn't line bore unless absolutely necessary.
In my opinion I wouldn't use stock rods on a bet. Although as others have mentioned at your RPM range cast rods would be fine but I have disassembled enough Pontiac motors with rod knocks that I wouldn't bother with them.

[Hesster1977]

You may find this useful for the build.
I sure did when I built my engine.
Courtesy of the HO guy's.
Your Parts list is spot on IMO. I would use Forged Pistons, keep the 2 Bolt Mains, and new ARP or Similar Rod Bolts.
The 455 is a great lower RPM torque monster, and not a 6000 RPM motor.

[hurryinhoosier62]

Originally Posted by tom s

JMO,no reason to change bolts on that engine.Tom

X 2, but I would have the machine shop doing the work to magnaflux the main cap bolts. Forty plus years is a long time to endure corrosive gases. Better to be safe than sorry. It's the same with the connecting rods. As Mike pointed out, the OE cast steel rods are up to use in a 5,200 RPM max street 455 with PROPER attention. This means magnafluxing the rods, checking them for straightness, installing quality aftermarket rod bolts, correctly resizing the rod bores, and torquing the rod bolts in the same manor as the machine shop torqued them before resizing the rods. A lot of us ran OE connecting rods in street engines long before the CCP forged rods became available. In my personal experience, I have seen few CCP forged rods that didn't need work to make them useable. Aftermarket rods from SCAT and Molnar, while based on CCP raw forgings, are machined here in the States.

[hurryinhoosier62]

Originally Posted by FrankieT/A

On another note I wouldn't line bore unless absolutely necessary.
In my opinion I wouldn't use stock rods on a bet. Although as others have mentioned at your RPM range cast rods would be fine but I have disassembled enough Pontiac motors with rod knocks that I wouldn't bother with them.

WHY would you align bore a block unless there are spun bearings or you are replacing main caps? Align HONING is a far better process to straighten the alignment of the main saddle as it removes a modicum of material when compared to align boring.

[FrankieT/A]

Originally Posted by hurryinhoosier62

WHY would you align bore a block unless there are spun bearings or you are replacing main caps? Align HONING is a far better process to straighten the alignment of the main saddle as it removes a modicum of material when compared to align boring.

I should have been a bit more clear....I would not align bore, hone or anything else....
The OP already stated the crank spun freely when the rods were off. My point was I would not touch the crank bore unless the clearance was too far to the edge and at that point I might try juggling bearings first.

[FrankieT/A]

Originally Posted by hurryinhoosier62

X 2, but I would have the machine shop doing the work to magnaflux the main cap bolts. Forty plus years is a long time to endure corrosive gases. Better to be safe than sorry. It's the same with the connecting rods. As Mike pointed out, the OE cast steel rods are up to use in a 5,200 RPM max street 455 with PROPER attention. This means magnafluxing the rods, checking them for straightness, installing quality aftermarket rod bolts, correctly resizing the rod bores, and torquing the rod bolts in the same manor as the machine shop torqued them before resizing the rods. A lot of us ran OE connecting rods in street engines long before the CCP forged rods became available. In my personal experience, I have seen few CCP forged rods that didn't need work to make them useable. Aftermarket rods from SCAT and Molnar, while based on CCP raw forgings, are machined here in the States.

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

[tom s]

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