Big Block Monster Stroker

[1971ls1longbed]

Hey, i need to know if anyone has used a 4.750 stroke crank in a 427 tall deck block to make a 555. A board member told me it was possible and i wanted to know if anyone else has done this. I do know the block will require alot of clearancing. I also know this is quite an ambitious build and its for a later transplant. I also intend to use this for a daily driver. If this is totally imposible i will just go 496

[ripdog28]

Don't know about 4.75 but have seen plenty of 4.50 strokes. Making 525 or so.
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[1971ls1longbed]

I'm going to keep doing my research because if this is possible it will be awesome
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[pockets]

The biggest I've heard is a 4.5 and some blocks will need a lot of clearancing with possible partial filling.

I too did a lot of research and the tall deck itself does NOT give you any more room than a regular block as far as stroked cranks go. It isn't like the 572 blocks are which has wider bore spacing. Biggest cube I've heard is a 525 and that is with a big overbore on a sonic checked block.

Even with a conservative 496 stroker you can use longer rods which are fairly common and the benefit of a 4bolt block
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[raceman6135]

It's not impossible to fit a 4.75" stroke crankshaft in a factory GM tall deck big block Chevrolet. But, it's not the easiest or least expensive build to do.

The problem with the factory big block Chevrolet blocks is that the main oil passage runs from the back to the front of the block along the oil pan rail. When clearancing the block for the crankshaft, it's very possible that you will grind into the oil passage.

Also, the coolant passages are at risk of being compromised when grinding the block for clearance.

The oil passage can sometimes be repaired by pressing an appropriately sized thin-wall tube into the oil galley. If you strike water, however, the block will either need to be welded by someone experienced with welding cast iron, or it must be brazed, or it must be fixed using something like a 2-part engine epoxy.

A specially clearanced oil pan will also be required to clear that size of a stroke.

Understandably, steel connecting rods are preferred, and really, are the only option -- aluminum connecting rods simply require too much clearancing.

If you plan on going this direction, work closely with your crankshaft, connecting rod and piston manufacturer(s) as there are many dimensions that must be considered. Using a crankshaft with cam-shaped counterweights will help, as will a rod that is forged with as small of a 'big end' as is possible.

Your connecting rod length will be dictated in part by what compression height piston you want to run and the shape of the crankshaft eccentrics your crankshaft manufacturer can supply.

For example, if you want to run a 6.70" connecting rod with the 4.75" stroke, the compression height of the pistons will need to be 1.12" which is very short. With such short compression height pistons, you will need to deal with the piston pin bore intersecting with the oil ring groove.

It's good that you're planning far in advance because as you can see, there's more to it than just grinding on the block

[KQQL IT]

Get a dart block. Go 598
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[pockets]

yea that's only $2300 for the iron cap version...

[thirdstreettito]

Get a 572. Solved!

This should help: http://answers.yahoo.com/question/in...5173832AAG5PNe

http://www.popularhotrodding.com/tec...ous_plate.html

[1971ls1longbed]

I know the rod to use is a billet steel rod and I think its 6.5.. the guy I'm getting the crank from has six rods for sale and i will pick them up too . im going to keep looking into it.
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[thirdstreettito]

The Edelbrock/Musi 555 uses Scat 4340 steel rods, why would you want to use aluminum? It melts at a lower temperature.

[1971ls1longbed]

I talked to my engine builder and he said its very possible and has done a few of them but not as daily drivers and the ones he built did NOT have block hard in them. We r going to do some experiments to see what problem I may run into. I do know the block will have to be CNC'd to keep flaws down to a minimum.
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[djracer]

I agree buy a dart block. If you are gonna try to race this motor in a truck go short deck 540 or so with aluminum heads. The weight needs to be kept to a minimum on the nose if you want it to hook.

[ripdog28]

$2-400 for the block (unless already have it) then $12-1500 for the machining to clear the crank and to clear the rods for the cam and what not. You will be well over $1500 at a minimum for this block which, IMO is not worth putting the money into when you can find deals on Dart or other blocks for $1800-2000 all day. Then again, its your money and your decision.

[djracer]

I got a really good deal on a bowtie block and could have bought a dart for about what I have in this one now. The dart requires so much less machine work and its much stronger. Sunset Racecraft quoted me a little over something like 2200 ready to assemble.

[Marv D]

What are the t /s and outlaw guys using to build these 600" BBC's?
My machinist had a 60x" alcohol injected BBC someone put a $10k deposit on, lost his job and bolted. He needed another $8k to pay it off.
I was like hmmm maybe I should

If I ever go BBC,,,, it will be somethng like that.

900 pound feet of torque from 4000-6800!!! You don't even have to beat up on these things!!!

[1971ls1longbed]

i am starting to lean towards a dart or merlin block so maybe ill go bigger

[djracer]

Don't buy the merlin. It takes much more machine work to make it right. Buy the dart in a steel block or a brodix if you go aluminum. I studied these hard when I was working on my motor.

[1971ls1longbed]

Originally Posted by djracer

Don't buy the merlin. It takes much more machine work to make it right. Buy the dart in a steel block or a brodix if you go aluminum. I studied these hard when I was working on my motor.

Thanks for the heads up im definitly going to look into a dart

[ripdog28]

598 Woohoo.... Here we go.

[1971ls1longbed]

Im thinking more along the lines of 632

[ripdog28]

Originally Posted by 1971ls1longbed

Im thinking more along the lines of 632

Are you ready to spend $4k+ on heads then new intake/dist/possibly change your brake booster, Headers..... List goes on for a tall deck. You can do a short deck for a lot less. Complete 632 will be over $15k alone then engine bay changes. 598 can be under $10k depending on what you reuse and no engine bay changes. 34CI isn't worth that much to me. you can make that up with some compression or a more radical cam/head combo.

[raceman6135]

Originally Posted by djracer

Don't buy the merlin. It takes much more machine work to make it right. Buy the dart in a steel block or a brodix if you go aluminum. I studied these hard when I was working on my motor.

I'll second this.

Iron block → go with Dart
Aluminum block → go with Brodix

[djracer]

Originally Posted by raceman6135

I'll second this.

Iron block → go with Dart
Aluminum block → go with Brodix

Thanks.
I told you I did my Homework!!!!!!!!!!!!!!!!!!!!!!!!!!!!

[thirdstreettito]

I have a question, why do you want to go 555? Why not add a turbo or supercharger to make good power?

[pockets]

Originally Posted by thirdstreettito

I have a question, why do you want to go 555? Why not add a turbo or supercharger to make good power?

you can make the same argument for any big block, you can just turbo a small block and do the same thing. Or hell why have a small block? call up ken duttweiler and get one of his 800hp+ turbo V6's.

Sometimes the point is to have a big engine, just for the sake of having it