[Hammertime Mike]

It's simple, PHS gives you the born on info. You want a kings ransom for the block. You have an avenue to justify the cost or just keep speculating.

[caddor38]

Ok i give up! You are all right there were no HO Yc motors. I am going to contact the owner of that GTO so he can sue mecum for that YC coded so called HO GTO..
Geez, now I know why Biden became president.

["QUICK-SILVER"]

Originally Posted by 'ol Pinion head

2= Pontiac division
1 = 1971 model year
P= Pontiac home plant. built B bodies & A-bodies
3004555 is the last 6 digits of the cars VIN

IF the last 6 digits had started with a 1 or a 2, the engine would have come out of a '71 Pontiac A-body built at Pontiac home plant.
As the last 6 digits began with a 3xxxxx, the '71 YC coded block came out of a B series (big car).
The two letter code YC engine was used for near 10 model years straight, 389, 400's, 455's, 350's... ALL of them basic D-port engines with standard log exhaust manifolds.

Clay

[caddor38]

Originally Posted by Hammertime Mike

It's simple, PHS gives you the born on info. You want a kings ransom for the block. You have an avenue to justify the cost or just keep speculating.

True, this is one of the few logical thought out post I received. I had mentioned before I am assuming this motor came out of a Grand Prix SJ.
The problem I have is that people are fighting over this block being the holy grail, an “HO” motor.
No matter what car it sat in most if not all sites define a 1970 motor with casting 483677 regardless of the two letter extension as an HO motor.

[caddor38]

Originally Posted by shaker455

cardor38,
The reason you ad has attracted negative attention is because your engine is not 455HO.
The information you have gathered is incorrect.
I would suggest removal of the ad or have form administrators do so.
Thx

Okay so can you go to all the pontiac website links i provided stating this is an HO block, mecum auctions who show a 1 of 242 GTO’s with a YC block that they are wrong. Once i get confirmation of at least one website the 1970 483677 casting block is not an HO i will humbly apologize.

[John Milner]

Your block came in a 71 model car. Look at your vin number’s 2nd digit.

[tom s]

Post 28 I told you to pull the PHS!We are now going on 47!Tom

[nas t eh]

Originally Posted by caddor38

Geez, now I know why Biden became president.

Insults and politics will not help you make your case.

Some of the guys helping you have 40+ years buying and selling Pontiac parts. You spent an hour on the internet to find bad information, and are using it to make your case.

Do you understand that there is a big difference between a 1970 455HO and a 1971 455HO. It’s about the same difference as the one between a RA3 and a RA4.

But your block as identified by the vin didn’t even come out of a car with a 1971 455HO as an option. So what are you hoping to accomplish, no one here is going to agree with your false premise.

[FASTASSBIRD]

Ther is no evidence the motor made it to a 1971 car and even the Vin indicates a really high number that shows its unlikey to been installed in a 71 vehicle.

21P304555

The 1 before the P is the year indicator making this in fact a 71 block

["QUICK-SILVER"]

Originally Posted by FASTASSBIRD

Ther is no evidence the motor made it to a 1971 car and even the Vin indicates a really high number that shows its unlikey to been installed in a 71 vehicle.

21P304555

The 1 before the P is the year indicator making this in fact a 71 block

Big car VIN started with 300,001.

Clay

[FASTASSBIRD]

Originally Posted by nas t eh

Insults and politics will not help you make your case.

Some of the guys helping you have 40+ years buying and selling Pontiac parts. You spent an hour on the internet to find bad information, and are using it to make your case.

Do you understand that there is a big difference between a 1970 455HO and a 1971 455HO. It’s about the same difference as the one between a RA3 and a RA4.

But your block as identified by the vin didn’t even come out of a car with a 1971 455HO as an option. So what are you hoping to accomplish, no one here is going to agree with your false premise.

This is arguably the most thought out response. (No offense to the other guys who had great responses).

The “YC” is the ENGINE APPLICATION code. Could it have mistakenly found it’s way into a HO car? Sure anything can happen on the line. More likely the application code was misstamped however then a complete incorrect block used. However this makes the YC coded block really only valuable to the original car or to someone who needs a 4 bolt main block. All models had application codes specifically (usually YS comes to mind.) to their line. That code determines the engine, the trans, heads, cam, etc. so knowing YC application ISN’T no matter how you cut it an HO code, we can safely assume it isn’t a HO block, or at least a correctly coded block. When guys open their hood it’s that code most enthusiasts look for, not the casting number or date code. It doesn’t take long in 52 years to swap a set of 4 bolt caps from a 421 or a 428, the 428 being a fairly common block so it’s also possible in 52 years that someone made themselves a 4 bolt block. Did it myself with a 69 428. And before anyone says anything I used ProGram billet mains lol so no one is gonna make the claim it’s original.
Lastly. Your claim of an hour spent searching, well I spent 5 minutes searching Joe Biden and found numerous sites saying how great he is. Guess that means he’s a great President? This isn’t a political forum nor do I agree so I’ll bring it back to cars. I can find misinformation for years on the internet that misinformation gets processed by guys who don’t know better and assume because they spent an hour trying to look for it and they found that it MUST be true. It perpetuates the cycle. It’s no different then the ram air casting heads for 70. One guy says he has 13’s and now 20 percent of the guys who aren’t open minded enough to study learn and take advice from guys in this hobby a HELL of a lot longer (some of em long enough to have bought some of these cars new) then the person trying to learn, sell, trade, collect. This site is full of guys who can spot the wrong shade of phosphate coating on bolts six states away., you might spend an hour researching on THIS site. Just my opinion.

[FASTASSBIRD]

Originally Posted by nas t eh

Insults and politics will not help you make your case.

Some of the guys helping you have 40+ years buying and selling Pontiac parts. You spent an hour on the internet to find bad information, and are using it to make your case.

Do you understand that there is a big difference between a 1970 455HO and a 1971 455HO. It’s about the same difference as the one between a RA3 and a RA4.

But your block as identified by the vin didn’t even come out of a car with a 1971 455HO as an option. So what are you hoping to accomplish, no one here is going to agree with your false premise.

Originally Posted by "QUICK-SILVER"

Big car VIN started with 300,001.

Clay

My point was the year designator is right there in front of the whole world. The argument we “we don’t even know for sure this was in a 71”. I’d say the vin pretty much proves it was in a 71.

[FASTASSBIRD]

The problem I have is that people are fighting over this block being the holy grail, an “HO” motor

There is no fight. It isn’t the “holy grail” of HO motors. That belongs to the WC hands down. Don’t believe me just try and buy one. Expect to spend 4K and up I would guess.

My gut reaction to the whole thing is that it was an extra they had sitting there so they stamped it YC and moved it out. I’d like to see the part number on the front main cap that will say a lot but I can already see something else on the pics that does lead me to think it was a legit original 4 bolt main block. Not uncommon for them to need a block and use the first thing that they could grab. Being a vin in the 4k’s (basing this on previous mentioned big cars starting at 300k.) would mean it was very early in the 71 year.

[caddor38]

Originally Posted by FASTASSBIRD

The problem I have is that people are fighting over this block being the holy grail, an “HO” motor

There is no fight. It isn’t the “holy grail” of HO motors. That belongs to the WC hands down. Don’t believe me just try and buy one. Expect to spend 4K and up I would guess.

My gut reaction to the whole thing is that it was an extra they had sitting there so they stamped it YC and moved it out. I’d like to see the part number on the front main cap that will say a lot but I can already see something else on the pics that does lead me to think it was a legit original 4 bolt main block. Not uncommon for them to need a block and use the first thing that they could grab. Being a vin in the 4k’s (basing this on previous mentioned big cars starting at 300k.) would mean it was very early in the 71 year.

Thanks for the reply, here is a picture of the main cap. I am assuming this is original 4 bolt main caps since this was a standard bore. It appears to be GM5 A77?

[caddor38]

Originally Posted by FASTASSBIRD

The problem I have is that people are fighting over this block being the holy grail, an “HO” motor

There is no fight. It isn’t the “holy grail” of HO motors. That belongs to the WC hands down. Don’t believe me just try and buy one. Expect to spend 4K and up I would guess.

My gut reaction to the whole thing is that it was an extra they had sitting there so they stamped it YC and moved it out. I’d like to see the part number on the front main cap that will say a lot but I can already see something else on the pics that does lead me to think it was a legit original 4 bolt main block. Not uncommon for them to need a block and use the first thing that they could grab. Being a vin in the 4k’s (basing this on previous mentioned big cars starting at 300k.) would mean it was very early in the 71 year.

Thanks for providing the info on the Vin. I thought the number was high with 7 digits, so can i assume this was the 4,555th car built in the 3,000 series in Pontiac Michigan. However, the motor began as a HO block since it was given a 4 bolt main. However since it was probably detuned to the 8.2 compression 325HP version folks are saying its non-HO and there are many sites calling the detuned vs an HO motor and some sites dont. My contention is that once they created the block in 1970, with a 4 bolt main and stamped it 484677, the block was then a 455HO according to my info.

[FASTASSBIRD]

Originally Posted by caddor38

Thanks for the reply, here is a picture of the main cap. I am assuming this is original 4 bolt main caps since this was a standard bore. It appears to be GM5 A77?

That’s the rear it looks like. I want to see the front cap looking down at the face of the block. Plus their should be a full part number on the cap. I’d have to go look at mine to see what the part number is but legit original 4 bolt blocks used a specific front main cap. In the end all that will tell you is it has the correct caps. Not a definitive answer to it being an original 4 bolt from the factory but certainly helpful info in the argument. Most guys who swap the caps just swap the center caps cause they don’t know better.

[FASTASSBIRD]

Originally Posted by caddor38

Thanks for providing the info on the Vin. I thought the number was high with 7 digits, so can i assume this was the 4,555th car built in the 3,000 series in Pontiac Michigan. However, the motor began as a HO block since it was given a 4 bolt main. However since it was probably detuned to the 8.2 compression 325HP version folks are saying its non-HO and there are many sites calling the detuned vs an HO motor and some sites dont. My contention is that once they created the block in 1970, with a 4 bolt main and stamped it 484677, the block was then a 455HO according to my info.

The big problem you face is yes the block was CAST in 1970. Unfortunate the cast date is in September of 1970. That means the block was cast AT LEAST 2 months into 1971 production. Casting and cars don’t run on the same Jan-Dec calendar we do. They run run on an august -July calendar with new models being available for purchase in sept. Meaning parts have to be cast as early as July for them to be able to produce cars for sale on sept 1. Your block being CAST after sept would then have to go through ALL the steps and processes to be ready to insert on an assembly line. In a perfect world with shipping manifesting inventorying transport to the line etc I’d say it would take at least 2 weeks to be ready to be put into a car. Now we are Oct in a perfect world. Maybe even Nov of 70. Well into the 1971 model year. My guess is like the WT motors of the 70 model year (also cast in the 69 year up til Dec) a few had 4 bolt caps added for god knows what reason. These things happen. However the YC code is the application code and idc if it has 6 bolt mains it’ll always be looked at as the base 455. I think your big hang up is it being a “70” block it isn’t it is a 71 which is why I took the time to explain the dating structure. Also the vin confirms that. I do think the mains were factory installed probably but not with the intent of it being a “HO” motor or “detuned” motor. Other then the caps the blocks are the same.

[FASTASSBIRD]

Originally Posted by caddor38

Thanks for providing the info on the Vin. I thought the number was high with 7 digits, so can i assume this was the 4,555th car built in the 3,000 series in Pontiac Michigan. However, the motor began as a HO block since it was given a 4 bolt main. However since it was probably detuned to the 8.2 compression 325HP version folks are saying its non-HO and there are many sites calling the detuned vs an HO motor and some sites dont. My contention is that once they created the block in 1970, with a 4 bolt main and stamped it 484677, the block was then a 455HO according to my info.

Btw it’s the 4555th built of that exact body line. Idk Pontiac assembly like I do Norwood and Los Angles. 4555 could be the 14555th car built if they did other makes models etc like they did at Los Angeles where they built damn near everything except the corvette

[caddor38]

Originally Posted by FASTASSBIRD

That’s the rear it looks like. I want to see the front cap looking down at the face of the block. Plus their should be a full part number on the cap. I’d have to go look at mine to see what the part number is but legit original 4 bolt blocks used a specific front main cap. In the end all that will tell you is it has the correct caps. Not a definitive answer to it being an original 4 bolt from the factory but certainly helpful info in the argument. Most guys who swap the caps just swap the center caps cause they don’t know better.

Here is the number on the cap

[caddor38]

Originally Posted by FASTASSBIRD

The big problem you face is yes the block was CAST in 1970. Unfortunate the cast date is in September of 1970. That means the block was cast AT LEAST 2 months into 1971 production. Casting and cars don’t run on the same Jan-Dec calendar we do. They run run on an august -July calendar with new models being available for purchase in sept. Meaning parts have to be cast as early as July for them to be able to produce cars for sale on sept 1. Your block being CAST after sept would then have to go through ALL the steps and processes to be ready to insert on an assembly line. In a perfect world with shipping manifesting inventorying transport to the line etc I’d say it would take at least 2 weeks to be ready to be put into a car. Now we are Oct in a perfect world. Maybe even Nov of 70. Well into the 1971 model year. My guess is like the WT motors of the 70 model year (also cast in the 69 year up til Dec) a few had 4 bolt caps added for god knows what reason. These things happen. However the YC code is the application code and idc if it has 6 bolt mains it’ll always be looked at as the base 455. I think your big hang up is it being a “70” block it isn’t it is a 71 which is why I took the time to explain the dating structure. Also the vin confirms that. I do think the mains were factory installed probably but not with the intent of it being a “HO” motor or “detuned” motor. Other then the caps the blocks are the same.

Yep, I concur and understand what your saying, yet there are a couple of ways to look at this. This particular YC motor with the 483677 stamp was made from July thru September and the later YC motors were given the 485428 stamp. The pontiac sites are calling the 483677 motors HO and the 485428 stamp non-HO motors. So, like a contract is written I am taking the verbage of what is written, however i do understand that folks may not want a motor that was installed in a vega or pinto in their GTO. However I think this motor could be considered a year correct HO motor as defined by multiple service bulletins abd pontiac sites.