Author Topic: 455 block castings  (Read 293 times)

DarcyL

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455 block castings
« on: January 09, 2019, 05:32:24 PM »
Hey everyone- I'm building a 1975 T/A, 400 auto car, and it has the 500557 400 block. I'm in Canada, and it is getting really hard to find core engines/blocks around here. A friend of mine gave me a 1975 455 core that I would like to build, but I was wondering if the 1975 455 blocks have the same light duty casting problems as the 500557 400 blocks do? Thanks for any info-
  Darcy

DarcyL

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Re: 455 block castings
« Reply #1 on: January 09, 2019, 06:16:56 PM »
Oops forgot to mention, the 455 is a 500813 casting block-

oldskool

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Re: 455 block castings
« Reply #2 on: January 09, 2019, 11:39:19 PM »
The 500813 is a good block. It's actually stronger than the 455 blocks which are drilled for 4-bolt mains, but have 2-bolt caps. instead of drilled & tapped holes, for the outside bolts, the 813 blocks have solid webs.

They do NOT have the thin webs like the "557" 400 blocks & the 500810 350 blocks have. I suppose Pontiac knew that the thin webs would not hold up in the long stroke, big journal 455, even with the reduced CR & power. 

My current 455 bracket engine has an 813 block.
« Last Edit: January 09, 2019, 11:47:18 PM by oldskool »

DarcyL

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Re: 455 block castings
« Reply #3 on: January 10, 2019, 02:24:49 PM »
Great! thats the info I wanted to hear- I picked it up as a core, but unfortunately, someone had already disassembled it, and let the crank and bores start to go orange with surface rust. It was a good motor at some point- .030 forged pistons, balanced rotating assembly, and 6x-4 heads with 1.77 SS exhaust valves, 7/16 rocker studs etc. The shame is after I passed a hone through the bores to clean them up, they're mic ing .0065/.007 piston to cyl. clearance. I guess it's .060 bore time. Too bad- the .030 pistons are in really nice shape-
  Darcy

oldskool

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Re: 455 block castings
« Reply #4 on: January 11, 2019, 10:28:29 AM »
"...they're mic ing .0065/.007 piston to cyl. clearance. I guess it's .060 bore time. Too bad- the .030 pistons are in really nice shape-..."


.040 over SP forged pistons are available.

https://www.ebay.com/itm/Speed-Pro-TRW-Pontiac-455-Forged-Flat-Top-Coated-Skirt-Pistons-Set-8-040/151059570877?hash=item232bda20bd:g:RFoAAOSwWTRWxMzD:rk:3:pf:0

Other forged pistons are available in a 4.185 & 4.190 bore size.

So, you won't have to go .060 over, from lack of piston availability. In fact, many cyl walls are not thick enuff to safely bore .060 over.

These Auto Tec pistons can be ordered with any pin height you want. The correct higher pin height can result in a zero or near zero deck height, without extra machining of the block decks.

https://shanonsengineering.com/collections/ebay-motors-parts-accessories-car-truck-parts-engines-components-pistons-rings-rods-parts/products/auto-tec-small-block-pontiac-400-428-455-flat-top-pistons

Although I recommend the Auto Tec pistons, here are some SRP 4.185 bore forged flat tops, which should be good.

https://pitstopusa.com/i-23906599-srp-pontiac-v8-f-t-piston-set-4-185-bore-5cc.html

https://www.summitracing.com/parts/srp-149721-8/overview/

Here are some forged flat tops, in a 4.190 bore size.

https://www.summitracing.com/parts/dms-6120bx-4190

https://www.cnc-motorsports.com/icon-ic888-040-forged-flat-top-pistons-4190-bore-pontiac-455.html

« Last Edit: January 11, 2019, 11:24:34 AM by oldskool »

Re: 455 block castings
« Reply #4 on: January 11, 2019, 10:28:29 AM »

DarcyL

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Re: 455 block castings
« Reply #5 on: January 11, 2019, 11:50:05 AM »
Thanks for the good piston info- I'll have to weigh my options- I'll definitely sonic the block before I bore any further-

  Darcy

Re: 455 block castings
« Reply #5 on: January 11, 2019, 11:50:05 AM »
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