[Vid]

Just about ready to start assembling my 455, a brand new motor with parts from several different sources. It’s a ‘77 400 #557 block (yep) for a “medium mild” street motor. As I’m getting closer to start the build, don’t know why but I just noticed that there is only one main cap that has bolt holes for the windage tray. Don’t they normally have at least 4? Is there a certain tray that I need for this block? Or did the #557’s not even bother because they were like 180hp? Can’t remember for the life of me what I did for a tray on the 400 I built for my Tempest wagon back in ‘08.


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[johnta1]

They only used a main cap to hold the oil tube.
No tray. Pan had baffling though.

[mgarblik]

The pan for that block would have a little sheet metal shelf to try and keep oil near the pick-up. You mentioned a medium build and that may have different definitions for various people. A build with 350 or so HP and no crazy hard cornering that may keep oil away from the pick-up, should be OK. If your ready to build, doing anything with the caps is out. If medium means much more HP, or lots of hard cornering, I would consider a Canton pan or the like for better oil control without a tray.

[Vid]

Originally Posted by mgarblik

I would consider a Canton pan or the like for better oil control without a tray.

Actually I do have a brand new Canton pan for it. Guess I’d better take it out of the box and check! Bought it so long ago (two years or more?) can’t quite remember what I got.

As for“Medium mild”, I’m going by today’s standards. Nothing crazy here. Pump gas 455 street motor. 4.25 stroke Butler kit, 10:1, 231* HFT Cam, 850 FST Carb, Out of the box round port CNC Edelbrock 87cc heads, 1 5/8 headers, Muncie, 3:60 rear. A big yawn compared to what gets most of you guys excited, haha. No porting, no Sniper, no big roller cam, no 5 speed. It’s just a little something to make me happy. “Medium mild”.


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[mgarblik]

Your going to make some power with those parts. Should be fine with the Canton pan. Your car looks nice. Are those aftermarket wheels you were able to use the PMD centers on, or Rally II wheels you had chromed? They look good. Chin spoiler. Lots of neat little details.

[Dragncar]

Originally Posted by Vid

Actually I do have a brand new Canton pan for it. Guess I’d better take it out of the box and check! Bought it so long ago (two years or more?) can’t quite remember what I got.

As for“Medium mild”, I’m going by today’s standards. Nothing crazy here. Pump gas 455 street motor. 4.25 stroke Butler kit, 10:1, 231* HFT Cam, 850 FST Carb, Out of the box round port CNC Edelbrock 87cc heads, 1 5/8 headers, Muncie, 3:60 rear. A big yawn compared to what gets most of you guys excited, haha. No porting, no Sniper, no big roller cam, no 5 speed. It’s just a little something to make me happy. “Medium mild”.


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Just my opinion but I would not put that crank in a 557 block. My buddy cracked every main with a 3.75 crank, RAIV cam can 62s. You are going to stress the block more than he did.

[tom s]

4.25 stroke crank would have me really question the build.Tom

[Steve C.]

4.250 stroke crank, un-ported KRE heads, Crower 60919 HFT cam, Performer RPM intake w/Q-jet carb and headers.....

502 HP at 5200 rpm

https://pontiacstreetperformance.com...455MikeG2.html

“Medium mild” build ?


.

[ekancler]

What do folks consider to be the safe limits of a 557 block? I’m sure opinions will vary.

[25stevem]

The first rule to adhere to 100% so that you do not fail any Block of a given strength level is to have the tune right and not detonate.

Grinding and polishing out and sharp casting or machined edges and in the main web area is a big plus also, especially all the sharp edges left from the drilling process in the Bearing oil feed holes in 4 out of 5 of the main webs.

[mgarblik]

The first rule to adhere to 100% so that you do not fail any Block of a given strength level is to have the tune right and not detonate.

The above statement by 25Stevem is so important and very true. Of even more importance when dealing with low quality, thin iron castings. At the designed production HP level of around 200 HP, the block is just fine. My personal opinion is a build above 400 HP is asking for trouble. I am sure hundreds of them have been built and survived at 500-600 HP maybe even higher. I should note that I am one of the nuts that ran a stock cast PMD crankshaft at over 1000 HP in a drag race application. So i am not easily scared. Just go into this knowing you are pushing the limit of the weakest Pontiac V-8 casting of them all. The long stroke crankshaft isn't going to help the situation. With the much stronger castings still being out there and pretty easy to come by, I personally wouldn't mess with a 557 block unless required by some type of rule requiring a certain year block. A good 400 core block can still be had for $500.00. Then all those "potential problems go away".

I should add that having a light weight rotating assembly will help the build as well as careful balance. If you bought a rotating assembly from Butler, verify that it is "final" balanced. Some rotating assemblies are "rough balanced" with the intention of the end user doing the final balance themselves. These "rough balance" assemblies generally take 30-50 grams on each end to dial in perfect. The idea with a rough balance is they are shipped heavy enough so that all you have to do is remove a little weight to be perfect, not have to add Mallory metal, which is expensive and time consuming.

[ekancler]

That's all great advice. I recall reading somewhere that using studs to secure the main caps might be helpful here. Any truth to that?

[Cliff R]

No, no real advantages using stud if you have factory bolts in good shape, just spending money in places you don't need to.....IMHO.....

[ekancler]

One other question about these 557 blocks. (I've got one in a numbers matching W72 T/A why I'm asking). What elements of creating more power are hardest on these engines? For example, increasing power by increasing compression and making other associated changes, i.e. more aggressive cam, as opposed to something like going to true dual exhaust.

Hopefully these questions are useful in the context of this thread...

[Vid]

Originally Posted by mgarblik

Are those aftermarket wheels you were able to use the PMD centers on, or Rally II wheels you had chromed? They look good.

The rallys were on the car when I bought it, but it had some pretty beat late 70’s aluminum center caps on them. I bought a set of correct year caps from OPGI and I’m very pleased with the look. Thanks for the compliment!


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[PunchT37]

I agree with Mike above. Light rotating assy. But, it seems like you`re ready to go with all your parts and the decision to go this route.


Either, start over or run what you brung. Might last on the street.

[25stevem]

The answer to that is to build it with added CID by means of bore and stroke to keep the motors intended rpm range not that much more higher then what it is now.

The fact is that the loads on the block go up with the square of the rpm!

So for example they are twice as high at 6000 rpm then they are at 4000 rpm.

A 400 557 block ( 3.750” stroke ) stroked to 4.210” ( that of a 455) is only adding 13% more load at any given rpm the motor was used in before, not 100% more load for every 2000 rpm increase.

If you increase your air flow by 13% ( easy to do) and then increase your intake port area by 13% ( once again easy to do ) and then turn your 400 into a 455 and then Cam it 6% larger ( like from 218 to 230 ) you can then have your cake and eat it too!

You will have more torque and hp then the 400 did and yet have the same drivability at low speeds that you had before, and all with just 13% more peak loading on the block casting.

It can hold up to that easily, but as the post above stated you want the reciprocating assembly to be balanced perfect!

By balanced perfect I mean the shop you pick for this should be able to balance within 1/4 once inch at 1” from the crank centerline.

The common what I call poor man’s balance job is done to + or - 1/4 once inch at 3” from the crank centerline.

Which is not what you want in a high speed engine, or one like a situation as with your block that has been strength compromised .

Look at it this and crank that is 20 grams out of balance at 3” from the crank centerline is 40 grams out of balance at 1” from the crank centerline .

PS.

A carefully fitted crank scraper brings much more Hp to the party then a windage tray does especially since your missing the needed 2 holes on the cap.

[Vid]

As far as the 557 block goes, I bought the block knowing it wasn’t the strongest thing out there but did so because of reading opinions on these very pages that usually they’re good for street use up to 450-500hp. Now the comments are like a complete about face. I’m not a guy who is going to drive like Dukes if Hazzard, I’m actually pretty easy on my cars. Of course there’s going to be the occasional stomp to 5500 or 6000. If I use this block (because now I’m full of doubt about it) I would definitely plan on chamfering all of the sharp edges within the block. It’s a shame because besides purchasing the block I sunk over $600 in machine work at the shop and they did very clean and precise work. I’m torn over what to do. I could dumb it down with a smaller cam and carb but that probably wouldn’t help much. I’d be more inclined to find a stronger 400 block .030 over and not have to worry. If anybody has one they’re willing to part with, feel free to reach out. If it’s reasonable I would consider it.


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[PunchT37]

Originally Posted by Vid

As far as the 557 block goes, I bought the block knowing it wasn’t the strongest thing out there but did so because of reading opinions on these very pages that usually they’re good for street use up to 450-500hp. Now the comments are like a complete about face. I’m not a guy who is going to drive like Dukes if Hazzard, I’m actually pretty easy on my cars. Of course there’s going to be the occasional stomp to 5500 or 6000. If I use this block (because now I’m full of doubt about it) I would definitely plan on chamfering all of the sharp edges within the block. It’s a shame because besides purchasing the block I sunk over $600 in machine work at the shop and they did very clean and precise work. I’m torn over what to do. I could dumb it down with a smaller cam and carb but that probably wouldn’t help much. I’d be more inclined to find a stronger 400 block .030 over and not have to worry. If anybody has one they’re willing to part with, feel free to reach out. If it’s reasonable I would consider it.


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Rpm`s and heavy rods/pistons are gonna stress the block more than hp alone. So, a smaller cam and or choked heads will help little.


If you have a heavy bottom end, street use with a 4500 to 5000 limit should be ok. 6000? Hmmm. Might do it a few times. Would NOT make that a habit.

[Vid]

Originally Posted by 25stevem

The answer to that is to build it with added CID by means of bore and stroke to keep the motors intended rpm range not that much more higher then what it is now.

The fact is that the loads on the block go up with the square of the rpm!

So for example they are twice as high at 6000 rpm then they are at 4000 rpm.

A 400 557 block ( 3.750” stroke ) stroked to 4.210” ( that of a 455) is only adding 13% more load at any given rpm the motor was used in before, not 100% more load for every 2000 rpm increase.

If you increase your air flow by 13% ( easy to do) and then increase your intake port area by 13% ( once again easy to do ) and then turn your 400 into a 455 and then Cam it 6% larger ( like from 218 to 230 ) you can then have your cake and eat it too!

You will have more torque and hp then the 400 did and yet have the same drivability at low speeds that you had before, and all with just 13% more peak loading on the block casting.

It can hold up to that easily, but as the post above stated you want the reciprocating assembly to be balanced perfect!

By balanced perfect I mean the shop you pick for this should be able to balance within 1/4 once inch at 1” from the crank centerline.

The common what I call poor man’s balance job is done to + or - 1/4 once inch at 3” from the crank centerline.

Which is not what you want in a high speed engine, or one like a situation as with your block that has been strength compromised .

Look at it this and crank that is 20 grams out of balance at 3” from the crank centerline is 40 grams out of balance at 1” from the crank centerline .

PS.

A carefully fitted crank scraper brings much more Hp to the party then a windage tray does especially since your missing the needed 2 holes on the cap.

Great explanation thanks Steve. You’re right, it is in fact a 4.210 stroke not 4.25. Been a couple of years since I ordered it and waited so long for all the other parts to arrive I had forgot. So there’s that.


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