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 Mild 461 out of a #557 Block?
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ledhed76
Cochise

USA
304 Posts

Posted - 18 Aug 2013 :  6:08:49 PM  Show Profile  Reply with Quote
Is this even an option as long as it is a street motor under 425hp?

Latech
Cochise

USA
397 Posts

Posted - 18 Aug 2013 :  7:04:38 PM  Show Profile  Reply with Quote
I am thinking it would be a waste of a stroker kit, not to mention the 557 block may not be up to the task of all the added torque.
You can get real close to 425 without stroking it.
Save the stroker kit for a stronger 400 block.
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ledhed76
Cochise

USA
304 Posts

Posted - 18 Aug 2013 :  7:59:35 PM  Show Profile  Reply with Quote
Well with a set of 6x-8 heads and a 557 block sitting around that is kind of hard to swallow
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cortcomp
Coyote

USA
5438 Posts

Posted - 18 Aug 2013 :  8:24:02 PM  Show Profile  Visit cortcomp's Homepage  Reply with Quote
I would guess it would be definitely doable and be ok. I mean we all want the top top greatest of everything, but for 425HP why not? If you're worried, maybe do blockfill and promise yourself you're not going to try for 500 later?

That being said, i see blocks around all the time, if i'm paying for machining, i'm looking for a better block. What's a couple hundred dollars when you're buying a $1500 stroker kit?
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bigD
Indian Spirit

USA
643 Posts

Posted - 21 Oct 2013 :  5:55:57 PM  Show Profile  Reply with Quote
I'm just curious. What is the most ya'll know of, that anyone has gotten out of a 557 block, and had it survive for a substantial length of time ?

Also, I've heard that the last few years of the 350 ('75-'77), the blocks were weak, just like the 557 400 blocks were. If so, does anybody have the exact casting numbers on these blocks? It seems that you never hear much about these.
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Blued and Painted
Chief PONTIAC

USA
3505 Posts

Posted - 22 Oct 2013 :  10:45:51 AM  Show Profile  Reply with Quote
Find some 72cc heads. Valve job, and contour to 76cc, mild clean up on the bowls, and build the hot 400. IMO



Bull Nose Formula/ 461/ Q-Jet/
TH400/ 3.08 8.5 / R44TS.
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Billy Martin
Two Feathers

25 Posts

Posted - 22 Oct 2013 :  10:49:35 AM  Show Profile  Reply with Quote
Not to trying to say it is the best option to do But I have a 461 eagle kit in a 557 block now. 6x-4 heads. 274 xe comp cam. Heads have been ported and polished 230cfm. Dynod 5800 RPMS. 378 horsepower on the ground. 3.73 gears The engine has been run basically between 4100 to 5200 rpms most of its life and it has been in the car since 2008 has approx 30000 miles on it. Really to think about yet. I do plan to find a good 988 block 1 day but so for it has not give me any issues.
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beertracker
Cochise

375 Posts

Posted - 22 Oct 2013 :  4:26:08 PM  Show Profile  Reply with Quote
[quote]Originally posted by cortcomp

I would guess it would be definitely doable and be ok. I mean we all want the top top greatest of everything, but for 425HP why not? If you're worried, maybe do blockfill and promise yourself you're not going to try for 500 later?

When adding blockfill this is going to displace coolant. Won't this negatively affect cooling efficiency?

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cortcomp
Coyote

USA
5438 Posts

Posted - 22 Oct 2013 :  4:28:53 PM  Show Profile  Visit cortcomp's Homepage  Reply with Quote
I would normally think so, but many have done tests (filling to the bottom of the softplugs) and had no adverse cooling issues. I think someone even reported a cooler running engine. I don't know how much heat is really concentrated at the bottom of the skirts anyway. Not sure that it'd add a ton of strength but would add some. I'd think that would be worth the benefit, to me anyways, as the stuff isn't as pricey as finding another block.
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Mr. P-Body
Running Bear

USA
2258 Posts

Posted - 22 Oct 2013 :  7:30:22 PM  Show Profile  Visit Mr. P-Body's Homepage  Reply with Quote


Ive seen several in the "old days" that were pumped up and ran for a long time. We didn't have chassis dynos on every corner in those days, so "who knows" how much power. But I recall at least two '77 T/As that ran 12s with the original short blocks still in them. That was all before we (at the "street racer" level) knew about things like "different" blocks... For the most part, a 400 was a 400 was a 400...

I'm sure, if you wanted a low-speed torquey "big car" engine, the 557 block would be excellent with a 4.25 stroke in it. Keeping the revs down is the key, IMO. Like the lighter Olds and Buick blocks, it "moves around" too much at higher speeds and power levels, binding (breaking) the crank. MANY a 403 died a horrible death that way...

Jim
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Quad
Tribal Scout

2 Posts

Posted - 24 Aug 2018 :  06:30:29 AM  Show Profile  Reply with Quote
What would be the safe rev limit with a 461 cube 557 block? There is a Firebird in the racers section of psp running 10.37 owned by Greg Miller. A 461 in a 1976 block built by CVMS. He shifts at 6000rpm.
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tjs44
Crazy Horse

USA
527 Posts

Posted - 24 Aug 2018 :  11:13:07 AM  Show Profile  Reply with Quote
I would not push past 400 HP if your building it for the long run.If me I would maybe limit it to a 4in stroke.Make sure the block gets line honed and has solid dowels and hope for the best.Tom
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Douglas Willinger
Sitting Bull

USA
139 Posts

Posted - 24 Aug 2018 :  1:43:46 PM  Show Profile  Reply with Quote
What about having the block cryoed?
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tjs44
Crazy Horse

USA
527 Posts

Posted - 24 Aug 2018 :  10:10:19 PM  Show Profile  Reply with Quote
Its not going to add any meat to those skinny mains.They took a lot of iron out of them.I built a 455 dyno mule with one that made right at 600 HP that is now in a 70 GTO that never sees much over 3500.Still running great.Would not do it for a car that was going to see many RPMs.Tom
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Corncob2061
Cochise

USA
249 Posts

Posted - 25 Aug 2018 :  09:55:58 AM  Show Profile  Reply with Quote
I should have a girdle available this winter for helping the 557 support more performance. It uses the stock caps, the only machine work required is line honing due to the main studs distorting the line bore. It should support 500hp. I PLAN to make it expandable into a cage girdle for more power yet. Can always email me if it is something someone wants to explore.

I am an Engineer, the Pontiac girdle has been a fun project. We also have a diesel pulling tractor with a full blown cage girdle and dry sump. Actually an I am a AgEngineer, basically the same as Mechanical engineer but I design combines instead of cars. Took a small detour to design something for a car, then back to combines. :) JAY

Edited by - Corncob2061 on 25 Aug 2018 8:02:47 PM
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Corncob2061
Cochise

USA
249 Posts

Posted - 25 Aug 2018 :  7:20:29 PM  Show Profile  Reply with Quote
I have noticed Miller had a 76 block too. Skip Fix was running one with ra4 heads at 12 flat. I have seen several people make big power like what Tom did. I read someone was down into the low elevens for several years then broke the block and crank. Many are running this block and have no clue it is different. Jim Butler told me the 4 inch crank works good in the 557 blocks. But he said limit the RPMs to 5000. He also mentioned he had someone build a 4.25 with that block and broke main saddles out of it.

I have noticed a couple guys using main studs and running the big crank on mild 500557 block street engines. That may help some, but stock it has plenty of clamping power, the whole main saddle is what is flexing. For this block only I like the roll pins better than the solid dowels. Most engine builders replace the pins with dowels though. I think they let the saddle flex without cracking at the dowel hole, and they expand to fill the hole better under stress. The dowel is where the block starts to crack at. It also seems to be more of a cyclic fatigue stress failure rather than a stress/strain failure. I think that is why the degree of success vary with this block. On a mild stoker build it could last a long time. Jay

Edited by - Corncob2061 on 25 Aug 2018 8:00:08 PM
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Steve C.
Chief PONTIAC

1866 Posts

Posted - 25 Aug 2018 :  8:21:27 PM  Show Profile  Reply with Quote
"Jim Butler told me the 4 inch crank works good in the 557 blocks. But he said limit the RPMs to 5000."

A truck motor :)

.

Edited by - Steve C. on 25 Aug 2018 8:23:41 PM
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tjs44
Crazy Horse

USA
527 Posts

Posted - 25 Aug 2018 :  8:35:32 PM  Show Profile  Reply with Quote
The real problem is IF you do brake one it usually puts stuff thru the pan and requires you to run over your oil.If your going 30 MPH its one thing but if in the middle of the track it could result in a very bad day.Tom
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Corncob2061
Cochise

USA
249 Posts

Posted - 25 Aug 2018 :  9:07:18 PM  Show Profile  Reply with Quote
Very good point Tom! Test vehicle = pontiac powered pulling tractor LOL
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Steve C.
Chief PONTIAC

1866 Posts

Posted - 25 Aug 2018 :  9:13:03 PM  Show Profile  Reply with Quote
Just a hunch but I suspect Skip didn't limit his to 5000 rpm.

http://www.pontiacstreetperformance.com/psp/rebuild400SF.html


.
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Quad
Tribal Scout

2 Posts

Posted - 25 Aug 2018 :  11:23:32 PM  Show Profile  Reply with Quote
See Butler performance website. They sell budget friendly short blocks using 557 blocks. These 557 short blocks are quote ... rated for up to 500hp only.

Jim Lehart is credited in Jim Hands book for block prep/ machining. In discussing 557 blocks the book says for high performance, higher rpm applications earlier production blocks are preferred. Jim Lehart built The 557 block in the Miller firebird. It would be at least 500hp to do 10.37 sec. with Trap rpm 6300.



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Steve C.
Chief PONTIAC

1866 Posts

Posted - 26 Aug 2018 :  11:28:24 PM  Show Profile  Reply with Quote
I contacted Skip....

At about what RPM did you shift this engine at ?


6500 with the HFTs the SFT pulled to 7000. HP peak with the 288/296 UD HFT was 6200.

http://www.pontiacstreetperformance.com/psp/rebuild400SF.html

.

Edited by - Steve C. on 26 Aug 2018 11:30:30 PM
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Corncob2061
Cochise

USA
249 Posts

Posted - 27 Aug 2018 :  12:04:48 AM  Show Profile  Reply with Quote
When I talk to Jim Butler the conversation went ...we sell the 557 with arp mains studs and rate for up to 500hp, but...recommend 350 hp builds...under 5k rpm...up to 4 inch crank...

A tech at butler said below 400hp and 5k. ..

I have read Rodney Butler has told people 450-500 is ok, but I bet if you talked to him he would qualify his answer just like his dad did...

I would rather do 425hp with arp main studs and a good 4 inch crank than 350 hp and the factory crank and std bolts. My 557 build is a 3.75 arma steel crank, with arp main studs, line honed with a halo girdle. 450 hp give or take. Mainly just a fun cruiser, with some drag strip time occasionally.

10.37 at 128 in a 3200lbs car my guess would be closer to 660hp...

I asked Skip about running the 557 is his car a couple months ago, he said he beat the crap out of it...I think he was running about 500hp

Tom had that engine that was just under 600hp for some dyno pulls..Those blocks can take some abuse, but you can only flex the main saddles so many times.. they are flexing on a 400hp engine too, just depends how your going to use and abuse it....Jay

Edited by - Corncob2061 on 21 Sep 2018 6:33:57 PM
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Corncob2061
Cochise

USA
249 Posts

Posted - 21 Sep 2018 :  5:59:58 PM  Show Profile  Reply with Quote
Someone told me 557s had week factory cranks, after studying them side by side with the older cranks there does not appear to be anything weak about them. They just have slightly lighter counterbalances. I saw on PY someone had one of the late cranks in a 600hp jet boat. Jay

Edited by - Corncob2061 on 21 Sep 2018 6:32:50 PM
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Douglas Willinger
Sitting Bull

USA
139 Posts

Posted - 21 Sep 2018 :  11:51:44 PM  Show Profile  Reply with Quote
Interesting numerical coincidence that the "557" Pontiac 400 block appeared in early 1975, when then U.S. Gerald Ford signed the bill making 55 mph the permanent U.S. National Maximum Speed Limit.

It was all part of a trend to down-spec our automobiles, such as the single core radiator in cars as the early 1980s intermediates. and as reflected by the scene I personally witnessed at a Yonkers, N.Y. Pontiac dealer service ares around 1985, of a service writer loudly berating a customer for admitting that he had driven his new Trans Am at 70 mph.

We all know what happened to the U.S. automakers' market share subsequently...
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