Pontiac 455 Questions

[87PontiacGP]

Hello all. I'm pretty excited, as I finally have been able to find a Pontiac 455 for sale in my area. However, I have a few questions. The seller says the engine is a 1971, YC 529126 or YG 529126 (I could not find the 529126 number researching..), engine code is: 485428. The date code by the distributor is: E 18 4. The heads that are on the engine now (stock) are the D-98-18 (I will possibly be purchasing 6x heads from this guy as well, but do not have any info on them yet..).

So far, I'v been able to conduct that the engine is in fact a 1971 455 2 main that was backed behind an automatic transmission (Y code specifies this), and came out of a B-body car, aka fullsized car. The YC code put's the engine at being a 4 barrel engine rated at 325hp, but the YG code lists the engine as being a 2 barrel engine rated at 280hp. The heads are "D" port heads with 2.11 intake valves and 1.77 exhaust valves. CC's of the heads are listed as 111 and HP is rated at 280hp. So, I'm deducting that the engine was originally a 2 barrel carb, which would put the code at a YG engine, not a YC engine. These heads seem pretty good for stock heads, though with the 111 cc chambers, compression is going to be down. The date put's the car at May 18, but I'm not sure of the meaning of the "4" in the code is. Probably something simple as date that I'm over looking..

Anyway, any Pontiac gurus able to help me out here with what I will be buying? I'm not sure if my deducting and research is 100% accurate, but does any of it sound about right? I don't plan to go huge with the modifications to the engine, just a rebuild, intake, 4 barrel carb, cam swap, and springs upgrade to allow more cam lift for now. I thought it was decent enough to snatch it up at only $350.. Thanks guys! 8)

 

[tdvick]

The 485428 is a 71 to early 75 455. The date code that you posted ending in a "4" would be a 74 motor. The head date code doesn't make sense. It should be similar to the block if they are original( letter=month, two digits=day, single digit=year). If they are original to the motor they would probably be "4x". That would be cast on the center exhaust ports.

 

[tdvick]

Hey,

Just wondering if you picked this up. I saw it for sale on another Pontiac forum and he posted that it has been sold. I looked at the pictures he had and it does look like a '71 motor. He had run some of the numbers together when he typed them so they didn't make sense. Probably a decent deal. Too far away for me though.

 

[deanlemans81]

Hey 87pontiacgp, have you actually seen this engine yet. Some of the numbers you give don`t match. First thing I would do is look for the displacement cast right on the right side of the block to see if its really a 455.

from the numbers you posted, this is what I have in my info.
block date code E184 means May 18th 1974

for the 74 model year, block code YC indicated a 350 2bbl

Your block casting number 485428 incicates a 73 455
for the 73 model year code YC I have 2 sources that give conflicting info. One also incicates 350-2bb and the other indicates 455-4bbl
Your YG code gives me a 400-4bbl in one source and nothing in the other.

If your date code is somply mis-read or mis-typed, for model year 71 both codes indicate 455 and your info is correct.
So check the side of the block to confirm the displacement and re-check your date code.

As for your heads, I agree with tdvick, your numbers don`t work. Please re-check your info.

BTW, I think it`s still a good deal, any good running Pontiac motor for $350. is a decent price and if it`s truly a 455, i`m jealous and want one
deanlemans81

 

[87PontiacGP]

Hey guys, thanks for all the information! 8) I'm mostly a Buick/Chevy guy so Pontiac's are out of my jurisdiction so to speak. :? Sadly though, I wasn't able to get this engine. 🙁 Life's little unexpected curves always has to get in the way of current goals it seems. There is a big probability that I goofed on some of the numbers or miss understood his email to me. It wasn't very in-depth nor easily understood on which numbers belonged where. 😳

Maybe it's for the better that I didn't jump onto this engine right away, even though it is a 455, and a Pontiac engine at that. I need to realistically look over my plans for this car more, though I do plan to have a big block, maybe for now going with a 454 would be a better option to start with while I hunt for a Pontiac 455 to match? :| But since this is a budget project, albeit a long one, it seems wasteful to go that route. :x Or, maybe just saying "forget the 455 and go with a Pontiac 400" would be the ultimate better choice. Not like I've been flip-flopping around with my decisions several times before.
/rant

Anyway, thanks bunches for the help though guys. 😀 I'll probably need some help with information on a Pontiac 400 or 455 down the road. Depending on if I have the patients to wait for a Pontiac 455 again or don't and go out hunting for a 400.

 

[deanlemans81]

Glad to help if I can. If you do come across a Pontiac 400 in good shape it is still a excellent engine to get. don`t give up and keep us posted.
deanlemans81

 

[dogsht]

Since numbers matching has no value for your use I say who cares what heads are on it or carb came on it originally etc.

Many used heads or poorly/cheaply redone heads will dictate; Street strip port job, performance valve job, bronze guides, often at least surfaced, better ratio & or adjustable rockers, bigger valves, for the best cost effective route of power & longevity. (remember the power in in the heads) ie this is not full race heads with all the extra work. Using Butler Pontiac Performance on the net prices thats about $1500 with your cores and no issues turning up or problems. Butler as do others Pontiac vendor/builders offer ready to go heads theirs are 1,695 plus porting (700)& core. Or you can get (what I would do) new light aluminum Edelbrocks from them 87cc 300+cfm pump gas street strip setup ready to bolt on heads for 2,495 and no risks of being cracked or warped or in need of being milled etc. This is the route most of generally should go for real performance pump gas driver project car.

You can start with a more readily available less expensive Pontiac 400 a side benefit is you can use the 3.00 mains which generally live longer as they don't make the heat when turning some rpm. Buy the whole matching ready to go rotating assembly. All you really want from your core motor is a good block and all the accessories motor mounts & such. You would get strong light weight pistons & rods with strong fresh crank for 3.00 mains, a 4.250 stroke & a 4.155 or 4.181 bore for 461 or 467 cubes. If you can't finance it you can find your core, then later buy your rotating assembly. They list theirs at 1699. Then heads as you can afford them then you & motor builder buddy can assemble it. So you break it down into as your time and finances allow. Core, rotating assembly, machine work, heads, distributor carberator rebuilds etc as needed, assembly, then tune. 450 to 500 HP plus 500+ torque isn't that tough to do on pump gas & reliably going this route even without it being race shop matched, assembled, & tuned. Oh yea and just can't stop grinning crazy fun to drive.

 

[87PontiacGP]

Thanks bunches guys. I'll keep everyone updated once I find an engine. :wink:

I mostly had posted this to get some general information on what I was buying. Just general information on the head specifications and what year block and everything so I could start setting aside some modding plans beforehand. I don't need a matching engine at all like you mentioned Dogshit, just get a plan worked out. 🙂

On a side note, I'll be retiring my Grand Prix from daily driver status. Hopefully I'll pull the trigger on buying an every day car I'll be looking at Saturday. I just couldn't use my girl in the winters up here. These cars have issues with rust as it is, I don't want it to be worse with our salt and other crap on the roads during the winter time. So, this will let me be more "radical" with my plans for this car, in other words. Will take longer to get to the finished product, but will be worth it. 8)

 

[87PontiacGP]

It's been awhile since I've been able to start thinking of my engine plans, but after looking quickly on craigslist I've decided I'm going to go with a 400 Pontiac engine. Keeps with the Pontiac theme I'm planning with this car, plus there are several engines in my area. My question now is: what year engine should I be looking out for with a Pontiac 400? I ran across a 1968 400 that came out of a GTO, 1971 400, and a 1973 400. All complete engines. Does it make much of a difference? Would some years be more durable than others in a Pontiac 400? Thanks again for the help again here guys, appreciate it. You all are more adverse to these engines than I am, coming from a Chevy/Buick guy. Looks like I'll be doing some homework on these when I got the time.

 

[Bonnewagon]

All 400's are roughly the same except for compression ratio and that is dictated by the heads. A stock '67-'70 4 barrel would be like 10.5 to 1 ratio and anything after '71 would be 8 to 1 or less. '71 -'72 heads are missing the end exhaust manifold bolt holes and require a beveled surface to seal. A '73 would be the first year for EGR in the intake manifold. Pre '70 engines have 2 motor mount holes on the side of the block and post '70 have 5 holes. To use the '78-'81 A/G body 301 mounts to put a 400 in our cars the 5 hole blocks are easiest to work with, although adapters are available to use the 2 hole blocks. '67-'69 F and B body exhaust manifolds dump wrong for our cars and '70 up F-B-A-G manifolds are correct. I say that because headers are rare to non-existent for a 400 in our cars.