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Olds 455 or pontiac 400/400

13K views 48 replies 6 participants last post by  handymann3 
#1 · (Edited)
Olds 455 or pontiac 400

Hey guys, you might have seen me in here before going on about a olds 403 but today I have a new question. I have a '81 trans am with a TH350 and a 3.73 posi. It is my first project/ car. This is going to be strictly a summer car since we have salty winters here in Canada. I am looking for a street and strip build. I plan on being at the track as often as I can. But I also need to get around town and very rarely on the highway. I have already picked up a olds 403 with the TH350 for pretty cheap ($150). Anyways I was chasing 450hp with the 403 and eveyone said to scrap it and go with the 455. As much as I protested I did go look at them. I came up with a Olds 455 from a 1970 olds toronado GT. That means it already puts me up there at 400hp and 500 ft lbs. So with some headers and mabey a intake and new cam I can get neer 500ish. The good part is it will only run me $500 bucks and after I sell the trans axle and all that comes with the from frame Mabye around $250. The bad part is that it got a little water down in one of the cylinders and now wont turn over. Another good thing is that the guy who owns it now put some diesel down the spark plug holes to mabye break it loose. It has been a while since he tried to turn it over again so who knows? Anyways what do you guys think? I have also seen mid 70's and very early 80's pontiac 400's. I am just wondering if I should risk the olds 455 (I think so) or just go with a pontiac 400? I am looking for the cheapest route to go so what do you guys say?
 
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#3 ·
Not to take anything away from the Olds 455, as it is a very powerful engine with a lot of torque, but if it has had water in a cylinder, it will need a complete rebuild. Boring, new pistons, and possibly one rod, if it hydro locked. The 400, on the other hand, unless it's been rebuilt, has cast pistons and rods, and if you're going to build it for performance, at the least, the pistons need to be changed. Performance isn't cheap, anyway you look at it!

Bill

 
#4 ·
DoubleVision said:
Olds 455`s are undersquare engines, meaning the stroke is greater in inches than the bore. With it`s good sized 4.125 inch bore and long 4.250 inch stroke, it`s a torque monster. Put the right pieces in it`ll shred the tires off that thunder chicken (firebird) with ease.
But if you put the right pieces in the "thunder chicken", we have a race!

 
#5 ·
WDCreech said:
Not to take anything away from the Olds 455, as it is a very powerful engine with a lot of torque, but if it has had water in a cylinder, it will need a complete rebuild. Boring, new pistons, and possibly one rod, if it hydro locked. The 400, on the other hand, unless it's been rebuilt, has cast pistons and rods, and if you're going to build it for performance, at the least, the pistons need to be changed. Performance isn't cheap, anyway you look at it!

Bill

Well, either way I was going to rebuild the engine no matter wich one I picked up so I am not to worried about that. I am not shure if water actualy got down there or just moisture from sitting so long. It has the air cleaner on and everything and even covered with a tarp. It has just sitting out behind a barn for a number of years. It ran when he cut the frame its just that it was to rusty to save. Also, it was rebuild before the guy got it so with the frame being rusty and all I am not shure how many km where put on it. I was thinking you could save the pistons if it wasnt to bad. just go with new rings, seals and bearings all around. Then just put a new cross hatch on.
 
#7 ·
WDCreech said:
If the cylinder is rusted at the ring, It will need to be bored, thus all cylinders need boring and new pistons.

Bill
So what do you say boss? Witch way should I go? Should I risk the olds 455? or go safe with the pontiac 400? If The 455 turns over I am def gunna pick that one up. Even if I need a re bore and new pistons, price wise is it worth doing the 400 insted? Both will cost me $500 just to pick up.
 
#8 ·
handymann3 said:
So what do you say boss? Witch way should I go? Should I risk the olds 455? or go safe with the pontiac 400? If The 455 turns over I am def gunna pick that one up. Even if I need a re bore and new pistons, price wise is it worth doing the 400 insted? Both will cost me $500 just to pick up.
It's your choice, but I'd be willing to bet that it will cost you substantially more to get the Olds running.

Bill
 
#9 ·
WDCreech said:
It's your choice, but I'd be willing to bet that it will cost you substantially more to get the Olds running.

Bill
So you say It will cost more just to get the olds running then to get the pontiac 400 to match the numbers that the 455 is putting out? I know more about olds then pontiac so could you point me in the direction I will need to go with the 400.
 
#10 ·
handymann3 said:
So you say It will cost more just to get the olds running then to get the pontiac 400 to match the numbers that the 455 is putting out? I know more about olds then pontiac so could you point me in the direction I will need to go with the 400.
I didn't say that. I said to get them running. The Olds, being stuck, worries me, but the Pontiac has the potential to be built to run with the Olds.

Bill
 
#11 ·
WDCreech said:
I didn't say that. I said to get them running. The Olds, being stuck, worries me, but the Pontiac has the potential to be built to run with the Olds.

Bill
Oh, sorry then. Well since I am shure you know alot about pontiac engine's just by looking at your dp. What should I do with the 400 if I want to get 450hp or more out of it and 550 or more ft lbs? I think it would be interesting to learn what goes into building a pontiac as well as making the Trans am a full blooded Pontiac.
 
#12 ·
handymann3 said:
Oh, sorry then. Well since I am shure you know alot about pontiac engine's just by looking at your dp. What should I do with the 400 if I want to get 450hp or more out of it and 550 or more ft lbs? I think it would be interesting to learn what goes into building a pontiac as well as making the Trans am a full blooded Pontiac.
I would go with one of the stroker kits available. There are a bunch of suppliers. http://www.jbp-pontiac.com/ , http://www.krepower.com/ , http://www.pacificperformanceracing.com/about-us.html , http://www.angelfire.com/fl4/pontiacdude428/kensspeedandmachineshop.html
They can be purchased balanced and in just about any configuration that you want.
 
#13 ·
I'm an Olds guy, but even I think there should be a Pontiac motor in a Firebird. If the 81 was originally a 301 motor, you should have all the parts needed to bolt in a Pontiac 400 or 455. The Olds motors in Firebirds use the Chevy-style frame mounts with an Olds-unique bracket that bolts to each side of the block and adapts to the Chevy frame mounts.
 
#14 ·
It's a SHAME the 455 got wet! Otherwise, that engine w/nothing but a set of pipes and maybe an intake (not that it really needs it, any more than the Pontiac would, as long as they're 4-bbl intakes) would run great in the T/A- even (especially, I should say) w/those highway gears that are likely in it now.

I put a basically stock Olds 455 from a wagon, into a 1976 Cutlass (buckets, console, nice ride- but HEAVY) when the Buick 231 went south. That car was an animal.

But if the Olds was wet long enough to lock it up, like everybody says, it'll take a bore and pistons/rings to put it right.

But before you do anything, you might want to go ahead and pull it apart to see exactly what you have. You just never know... But be prepared for the worst.
 
#15 ·
cobalt327 said:
It's a SHAME the 455 got wet! Otherwise, that engine w/nothing but a set of pipes and maybe an intake (not that it really needs it, any more than the Pontiac would, as long as they're 4-bbl intakes) would run great in the T/A- even (especially, I should say) w/those highway gears that are likely in it now.

I put a basically stock Olds 455 from a wagon, into a 1976 Cutlass (buckets, console, nice ride- but HEAVY) when the Buick 231 went south. That car was an animal.

But if the Olds was wet long enough to lock it up, like everybody says, it'll take a bore and pistons/rings to put it right.

But before you do anything, you might want to go ahead and pull it apart to see exactly what you have. You just never know... But be prepared for the worst.

Well I would really love to get te 455 but with the whole wet thing I am really worried. I dont wanna get screwed with the 455. The last thing I need is another boat anchor. IF the 455 came un stuck after soaking with the diesel I will pick its up. I was thinking a couple of things though. If the diesel fuel didnt work what are the chances of engine oil, alot of wd 40, break fluid or as much as I am afraid mabey some light heat? I dont mean mix them all togeather I just mean witch is most likely to work? Another thing I was wondering is what it would cost to bring the 400 up to the 500hp mark like I was going to do with the 455 compaired to the cost to just rebuild the 455? Finaly though, If The 455 is stuck why not just take the E heads on it, get some flat tops and put them on the 403 with a new cam and headers? It would save me some money not having to pay another $500 bucks for a 400 and it would put me around 450hp or more. I was thinking that if I go this way and do the 403 I would just use it untill it blows up and then get a 455?
 
#16 ·
handymann3 said:
If the diesel fuel didnt work what are the chances of engine oil, alot of wd 40, break fluid or as much as I am afraid mabey some light heat? I dont mean mix them all togeather I just mean witch is most likely to work?
First, empty it of water. Skip the brake fluid- it collects water from the air. No real way to effectively get heat to it...

I like PB Blaster as a penetrant, hands down. I'd try to level one side at a time (if the whole engine got wet but usually only a couple cylinders get it bad) and spray enough PB to cover the top of the affected piston(s). Let sit overnight, repeat for the other side/affected cylinders. Then 'rock' the crank back and forth, loosening it (hopefully) as you go.

If The 455 is stuck why not just take the E heads on it, get some flat tops and put them on the 403 with a new cam and headers?
I'm no expert on Olds heads, but most of the time guys use 350 heads w/larger valves for the 403.

Depending on the variables, you could get about 9:1 CR w/the 455 heads (80 cc chambers?), w/o milling, and w/a 'zero' deck.

No matter, if it were me, I'd grab the 455, locked or not- as long as you have room for it.

Was this a Toronado engine? I might have it mixed up w/another thread...
 
#17 ·
cobalt327 said:
First, empty it of water. Skip the brake fluid- it collects water from the air. No real way to effectively get heat to it...

I like PB Blaster as a penetrant, hands down. I'd try to level one side at a time (if the whole engine got wet but usually only a couple cylinders get it bad) and spray enough PB to cover the top of the affected piston(s). Let sit overnight, repeat for the other side/affected cylinders. Then 'rock' the crank back and forth, loosening it (hopefully) as you go.

I'm no expert on Olds heads, but most of the time guys use 350 heads w/larger valves for the 403.

Depending on the variables, you could get about 9:1 CR w/the 455 heads (80 cc chambers?), w/o milling, and w/a 'zero' deck.

No matter, if it were me, I'd grab the 455, locked or not- as long as you have room for it.

Was this a Toronado engine? I might have it mixed up w/another thread...

Yea, its out of a olds Toronado GT. Only one cyl got wet. I am not even shure if its wet, it has a air cleaner cover and a tarp on it. I have a feeling its moisture from sitting so long. It has just been sitting behind a barn for years. It was out of a running toronado that was rebuilt but the frame was no good to he cut it just behind the trans when he bought it. I think the engine was the only reason he bought it because he has had ALOT of these cars over the years. So when he went to go take a look at this engine when he wanted to put it in one of his cars he hooked the starter but no luck. so he took the fan off and tryed to turn it over with a breaker bar or somthing, still no luck. so he took the plugs out and looked down the cylenders and said he saw somthing ( I dont really know what). He said he only saw somthing in one of the cylenders so he put diesel down all of them and left them to sit. It has been sitting since the summer now. He said he didnt bring it into the shop or do anything to it really. so with the tranny attatched still I am wonderig if mabey its stuck and thats why It wont spin? or mabey its the alt or ac or any other belt drivin things? It has been sitting a long time and alothough its covered it still got moisture and started to rust. I will post again with pics..
 
#20 ·
Yea, It does. I still think its from sitting so long. And with this being canada with all the snow, Once it melts... you know where I am going. All the moisture and with the weeds and grass and such growing under the tarp. If you look at he picture the bottom of the engine is more rusty them the top. This makes me think that the rust on the bottom is from the snow and growth as I said and the top rust is from moisture age and just sitting for a number of years. After seeing the pictures what do you say?
 
#21 ·
handymann3 said:
Yea, It does. I still think its from sitting so long. And with this being canada with all the snow, Once it melts... you know where I am going. All the moisture and with the weeds and grass and such growing under the tarp. If you look at he picture the bottom of the engine is more rusty them the top. This makes me think that the rust on the bottom is from the snow and growth as I said and the top rust is from moisture age and just sitting for a number of years. After seeing the pictures what do you say?
I'm game for any big displacement engine. If you got room and the price is right, why not?
 
#23 ·
cobalt327 said:
I'm game for any big displacement engine. If you got room and the price is right, why not?
Well the price is right. Its just that I only have one shot picking up another engine! I would LOVE to get this 455 but is it worth running the risk of paying $500 for cyl heads a intake and carb? Plus being stuck with the trans axle? and eveything else? I know I can sell them but I rather not go through the pain of having people asking me stupid questions about it and wasiting my time. I also sorda had a few idea's with the trans axle. I think I will put a new post up on how to build up a ponch 400. Unless The 455 comes loose I am probobly going for the 400. Or last resort is the 403.
 
#24 ·
WDCreech said:
Being that you're in Ontario, That engine has been exposed to freezing temperatures and if there was enough water in a cylinder to crack a cylinder wall, it's toast. I personally wouldn't waste my time.

Bill
I never actualy thought about that. I am glad you brought that up. I think thats what just sold me on the poncho 400. I just posted another thred on a pontiac 400 build up if you wanted to see what others have to say...
 
#25 ·
You'd pay he!! getting 450+ hp out of the 403. Especially with the whimpy main webbing. On the other hand, with the kits available for the 400 Pontiac, from the shops that I gave in post #12, you can make a, safe, 455, which would be stronger than a Pontiac 455 block, with about 550 hp. By "safe", I mean with just a .030 bore, and not have to worry about cylinder wall thickness. With a sonic check, you may find that it can be bored as much as .060, but that would be iffy for street use.
 
#26 ·
WDCreech said:
You'd pay he!! getting 450+ hp out of the 403. Especially with the whimpy main webbing. On the other hand, with the kits available for the 400 Pontiac, from the shops that I gave in post #12, you can make a, safe, 455, which would be stronger than a Pontiac 455 block, with about 550 hp. By "safe", I mean with just a .030 bore, and not have to worry about cylinder wall thickness. With a sonic check, you may find that it can be bored as much as .060, but that would be iffy for street use.
I love the idea of these kits but holy f@&%. I took a quick look because it was way early in the morning over here when you sent them. I was prices from $500- $2000. I think I am going to take another look now.
 
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