# 400 w/ YH code?



## leeklm (Mar 11, 2012)

I am all Googled out... My block ID of 481988 is shown as an early 70's 400. On the right front of motor, the ID# is 001846 YH. On the back top of block, I see a date code of D294 (hard to read, I think this is correct, but maybe the 9 is a 7, for 1974?). The heads are 5c-8 with a date code of F124. Looks like the heads & block possibly match??

Anyway, I am unable to find a code YH for the 400, only a 455. Is it possibly from a service replacement block?

Any insight from the experienced code-busters on this site would be great!

Thanks.


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## 68greengoat (Sep 15, 2005)

1974 400 190 HP *YH* A 8.0 255 *4X* 1-2 7044066 Block Casting # *481988* 

According to Wallace Racing and another source, 5c heads were used in '75. But since your date code is June 12 1974, that seems a little early to be putting those heads in a '75. 

Here's a '75 YH/481988:
1975 400 170 HP YH A 7.6 266 *5C* 1-2 7045160 Block Casting # 481988/500557


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## leeklm (Mar 11, 2012)

Thanks, I did see that at wallace as well. Looks like the heads/motor are likely a match set. The F124 code on the head shows a June 1974 mfg date, which was likely installed in a 1975 model year, which appears to match the block as well. 170hp, woo hoo! Explains why I want a little more grunt  Although with a 4spd, headers, and 4bbl, it actually feels better than what it looks on paper! Good news is that I can stop putting 92 octane in the tank, and save 20 cents per gallon with 87 oct...

I recently had the timing cover off to replace a leaking front crank seal, and had what appeared to be the original timing chain "flopping" around that I replaced. I would not be surprised if I have a virgin motor. Wish I could say that for the car! Oh well, should provide good stock for a future stroker kit. Damn, the parts mfg's must love us!


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## rocket2017 (May 16, 2018)

*Question for the experts*

Regarding the 400 w/YH code:

Wallace shows:

Year	Engine	HP	Engine code	Trans	CR	Cam	Head Code	BBL	Carb No.	Misc
1974	400	190 HP	YH	A	8.0	255	4X	1-2	7044066	Block Casting # 481988
1975	400	170 HP	YH	A	7.6	266	5C	1-2	7045160	Block Casting # 481988/late 500557

I've read a little about the later model engines from the mid-seventies and see that Wallace indicates around a 50% decrease in HP between 1970 and 1975. How much of that is due to "non engine block" modifications (i.e. carb, intake, headers, etc. selection that restrict airflow) and how much of that is due to "engine block" modifications that restrict oil flow and/or cooling of the block. That is, if you take a later mid-seventies 400 block, bore it out and stroke it, then bore out the heads and intake module, and throw in a high quality carb or EFI unit, can you achieve similar results to stroking out a 1970 400 engine, which stock made about double what the mid-seventies engine made, and with a stroke kit, can easily top 500 HP or even 650 - 700?


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## firemedic835 (Sep 22, 2017)

Ok guys, I need some help.


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## BearGFR (Aug 25, 2008)

68greengoat said:


> . But since your date code is June 12 1974, that seems a little early to be putting those heads in a '75.


I think it's reasonable that it's a model year '75. The engine foundry is known to have switched over to casting for the next model year at "about mid year".

That along with the other evidence leads me to think it's a '75.

The casting number. ***557 blocks are the ones that have weaker main webs and as such are questionable for high horsepower stroker builds. You've got a **988 which is much better for building a serious engine than the ***557 would be.

Bear


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## 68greengoat (Sep 15, 2005)

BearGFR said:


> I think it's reasonable that it's a model year '75. The engine foundry is known to have switched over to casting for the next model year at "about mid year".
> 
> That along with the other evidence leads me to think it's a '75.
> 
> ...


Hey Bear, I see you're still modding. Wholly cow. Just got and e-mail notification. This thread is from 2012. Been awhile since I sold the Goat..... I still have the street rod.....


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## BearGFR (Aug 25, 2008)

Ooops.... well, it showed up on the 'active topics' list today because of some recent comments on the thread. I wasn't paying attention I guess ----- I blame it on olde age.

Bear


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## firemedic835 (Sep 22, 2017)

What do I have here?


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## firemedic835 (Sep 22, 2017)

I need help, what do I have? 1964 GTO


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## Pinion head (Jan 3, 2015)

as we surmised last week, if it's a WJ stamped '67 usage block, it's the man trans applicaton 428 HO block. A better straight on pic of the font of the J would help.


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## firemedic835 (Sep 22, 2017)

I’ll try to get a better pic


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## firemedic835 (Sep 22, 2017)

I got a mirror and got a better look at the engine code it turned out to be a WT , I also found a H306 WC motor. He wants 300 for all. It looks good.


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## firemedic835 (Sep 22, 2017)

Here is another one I found, $700.00


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## firemedic835 (Sep 22, 2017)

$700.00 for the 27P with the transmission and it is running.


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## Pinion head (Jan 3, 2015)

The '67 YC code big car 400 2bbl engine is nothing special, but in good shape, & for $300, it would provide an early (H of 66) block core for someone with intentions of resurface and gangstamp...yes, it happens, that is the market. Also the '67 YC appears to have decent '67 8 bolt timing cover, & the std bore forged TRW pistons have some value. Wont know condition of the crank till shortblock has caps pulled and bearings and crank are examined. The 143 heads are doorstops worth about $15. Pulling cheap 400 cores out in the country yards, I used to haul in & stack up nothing heads like that if I couldnt grab a pair of later 6X or 5C heads. Then as out of town Pick-N-Pulls would try and gouge me for a core charge on heads, would always have a pair of chunker heads in the back of the truck to haul in.

On the 64 389 27P coded engine, just silly money as a low horse '64 big car 4bbl engine & trans, just too much... Now am sure someone on here will disagree, but few honest folks are playing Carlot Tony & trying to pull the con that because it's a '64 Pontiac 389, it ought to be "correct" in a '64 GTO engine bay. Such an engine is far from correct! Carlot Tonys & Contraption builders, both I share the same level of disgust for, both types have wasted so much of many of our time. Buying such an engine and trans, on the transmission, would need to find numerous Cruiser type Pontiacers with '64 and earlier 60's big cars, one might be able to sell the transmission, but typically the big car cruiser type buyer is beyond cheap, you'll end up burning up your gasoline to haul it two county's away to give it to one of them.

On the engine in your '64, looking at yesterday's pics, the stamped two letter ID code did look more like a WT with a scraped "tail" on the bottom of the T. the last '67 engines I pulled with the letter J stamped in the 2 letter code were XJ coded 400's out of a pair of '67 GP's. Both had good core '670" heads, the reason I pulled both long blocks. Been so long, cannot remember the font of the J stamping, if it had a line on top. Glad you examined the block face closer. While not as valuable as a '67 428 HO WJ short block, the '67 WT will have more demand if you decide to sell it off after finding a correct dated '64 76X block. 

Hope this helps!


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## firemedic835 (Sep 22, 2017)

Ye it does, thanks again Roger


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## firemedic835 (Sep 22, 2017)

After taking a few days to think about what you said. I decided to keep the 400 in the car, just to have fun driving it. I’ll take my time looking for a 76x to build for later down the road. The 76x is the only thing I need to have a numbers matching car. I did speak to Mr. Williams ( the original owner from 1964 ) he purchased it when he left the military in 1964. He said he swapped the motor in 1968. The car has 76k miles on it. He also gave me the original wheels, red wall tires and deluxe wheel discs (Hub caps). I don’t know why but he also had second set of all the Pontiac emblems ( still in the original Pontiac boxes ). All the window, door, hood and trunk seals. I’ll try to attach a picture of her the day I drove her home. He said he was going to repaint it but never got around to it. It does however look like he had some small repair around the lower portion of the doors and lower part of the rear window.


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## firemedic835 (Sep 22, 2017)

I bought it October of 2017


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