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Discussion Starter #1
Well in the past few days I have taken a renewed interest in my big blocks I bought a last fall.

The motor in question is a 454...Casting # 861959 and serial # 705257xh.


So today I took my crankshaft that I got to the machine shop.We found out it was for the 454.It's is a steel crank.I believe he said it had already been turned .030 on the mains and .020 on the rods.And it needed to be turned more.Not sure how much yet.Supposed to be done next week..

Also since it is for the 454 that means that the pistons that I have are domed.Part # 252-97.Which supposedly is a replacement for the ls-5,ls-7 engines.

The heads I have are 781's.I have found that they either have 118cc chambers or 113cc.

So my questions are will the crank being turned that far make it alot weaker.Say not worth using?

Does anyone know anything about these pistons?The only #'s I can find are inside the piston.

Are the 781's 118cc or 113cc?I know acctaully measuring them it wont be accurate but I am talking straight from the general.


Thanks for any help.I took the crank there thinking it was for my 396 and turns out it's for a 454.Which changes everything!:no:
 

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My 781 head cc'd in at 125cc's, so you need to check them. The crank will be fine as long as it's turned correctly and they leave a nice fillet radius on the journals.

The pistons you refer to have a 50cc dome and will give a 12.5 compression ratio with the 118cc heads. But, the number you list is a forging number for part number L2308F, which is a 427 piston with the LS7 style dome on it, which is a L88 piston. Looks like you're going to need new pistons.
 

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Discussion Starter #3 (Edited)
Man oh man.This is crazy.

I have learned a valuable lesson here.First and foremost don't buy anything when you don't know EXACTLY what you are buying.

Basicly I bought a bunch of good bbc parts.None of them are interchangible with each other and even the one's that work with each other are missing a big key part.

Such as the 396.I have a standard bore 4 bolt 396 block in very good shape.A fluiddamper 396 damper,a brand new scat sfi 396 flexplate,Nice set of forged flattops with rods for a 396.

For the 454 the parts listed above.Along harland sharp roller rockers and a whole bunch of other bbc parts.Including a polished 8-71 supercharger setup.

I can't believe this.I sold 90% of my small block stuff to make room for this stuff and it's all bunch of none interchanging stuff.AHH!!!!!!!!!


This just isn't my week!And thanks BTW....
 

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You're still in fine shape. The rods will work in the 454. Now, if you sell the balancer and flexplate, then buy the correct pistons for the engine and compression you want, you'll only probably be out the price of the new balancer. Now sell those 396 pistons, and you should be able to ALMOST break even on a good short block. Sell the 396 block and now you've gotten yourself a nice 454 shortblock and a little cash. Just be patient and you'll figure it out. If you need to get rid of that 396 block, I may be interested for the right price. See, now you're ahead already:D

Here's some ideas. First a good forged piston:
http://kb-silvolite.com/forged.php?action=details&P_id=367
http://store.summitracing.com/partdetail.asp?part=UEM-KB782-030&autoview=sku
A new balancer:
http://store.summitracing.com/partd...&N=700+4294908216+4294840133+115&autoview=sku
And flex plate:
http://store.summitracing.com/partdetail.asp?part=SUM-G102SFI&autoview=sku
It's not cheap, and you can probably find cheaper pistons, but this is just and idea for you.
 

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Discussion Starter #6
Well today turned out a little better.

First off I went to the machine shop again and explained to him I didn't have the correct balancer.He was going to put another key way in the crank and balancer for the supercharger setup.Since he can't do that at this time I told him to order the correct rod and main bearings.So that parts taken care of.

Second off I found out the guy doing the machine work has built race car engine's along time.(He's probably in his late 60's)So my engine should be in good hands.....

Included with my engine was a set of RPM machine 6.385 I beam rods.There brand new still in oilly wrapping in the box.The pistons I found that work with these rods and a stock stroke 454 cost 850 bucks.Around 8.50:1 compression.(Around 10 pounds of boost.)I am pretty sure there the one's I going with.This engine will be supercharged eventuallly.Whenever the trans and rearend along with a cage are all up to the task of 800+hp.

Not sure on selling the 396.I need to my taxes done and see how that sets me.If I just keep working at it steady I bet I could keep it and build the 454....
 

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Yep, I thought you'd find those rods in there. That was to make the tall deck block you had work. A 10.2 block with those long rods, a 454 crank and a set of 427 pistons puts you at a .030 deck height. Shave the deck .010 and use a .020 shim gasket and you're in business. Well, good luck on the build.
 

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Discussion Starter #8
The reason this guy had these rods is because he was wanting to build a 496 stroker.(I decided not to do this due to clearance issue's)I don't have a tall deck block.I am not sure what you are talking about?

The 427 pistons I noticed are on a set of factory style rods.Although they do have a 7/16 rod bolt.Which the machinist told that they are for an l-88 also...
 
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