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Planning future 427 build

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Old Nov 29, 2012 | 09:09 PM
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Originally Posted by Blackpanther99
I am about to start a project with a 427 also, but off of a 6.0 Iron block... forged crank, forged low compression pistons, forged bottom end, bored over .60 etc etc... Its going to be a boosted engine with a PT 88mm .96 AR Housing on Meth (Snow's) havent started on it yet, I want to get everything together first before starting. My Trans Am at the wheels should push anywhere from 850-950RWHP but I dont want to push over 20PSI because walls are too thin. In a 7.0 block you can easily push 20psi, its a strong iron block. I think Aluminum blocks are more safe for Nitrous than for any other boost set up in my opinion
It's not the walls you need to be worried about, it's the pistons. To fit in a standard deck block, they typically have a compression height of about 1.0x" which is relatively thin and flimsy. Not to mention, the rings are exposed to even more heat since they will be moved further up closer to the point of combustion in the cylinder. You would be much better off just honing to 4.005" and using a 4" stroke for 403ci. It will last longer and can handle more boost.

Originally Posted by bayer-z28
Going in my 4th gen Z28.

I've been wanting an LS7 lately, but I think that may be a bit more of a hassle. We'll see what the GenIV group thinks.

My reasoning lately is that I'm pretty much wanting something that drives like stock. Granted My PatG Cam is pretty "tame" but with the 102/102 intake and ~500flywheel it makes it kinda punchy. And it's getting to the point in the game where I have to start keeping track of mileage and uses on everything in the car, and will have to look into replacing the valve springs soon, new push rods, replace the rocker trunions. Uuugh..It's a lot of babysitting for a street car. Not to mention the return fuel system I have. But I'd like to pick up where I left off HP wise.

No High maintenance TT setups please ($$$$$ also.) No real budget idea yet. But maybe under $10k for the engine after all is said and done. My trans and fuel system is built fine, so I don't have much else to worry about.


Here's what I was kicking around the noggin: Either an LS7 crate engine with a pimp set of West Coast heads (or equivalent,) slightly milled.....That's it. Looking for about 550flywheel or 480rw. Can I do a wet sump LS7??

Or else I could try and find a built shortblock 427 from an LS3 or L99, with a very good set of heads, milled slightly to bring the compression up a bit. If I were to do a cam, I would want something VERY mild, with maybe a 115 or 116 lobe separation and so I can either run stock springs or a very long lasting set of equivalents. Was thinking a good set of beehive single springs.


Just looking to spit-ball some ideas here... Just future planning....Maybe I just need a C6Z..

Thanks for the advice.
Bolt-on LS7's are making about 500whp naturally aspirated, so "pimp" heads would be way overkill for a 480whp goal. Something as simple as a 416ci LS3 would suffice and still be well within your $10k budget.
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Old Dec 4, 2012 | 10:24 AM
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Soo you suggest changing my pistons?
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Old Dec 6, 2012 | 12:30 PM
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Originally Posted by Blackpanther99
Soo you suggest changing my pistons?
Yes, crankshaft too.
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Old Dec 6, 2012 | 04:42 PM
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Originally Posted by KCS
Yes, crankshaft too.
why the crankshaft too?
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Old Dec 7, 2012 | 06:52 AM
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Originally Posted by djfury05
why the crankshaft too?
To get 427ci from a 4.06" bore block, you need to use a 4.125" stroke crank. That stroke will require a 1.0x" CH piston, which is relatively thin and consequently weak for a boosted application.
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Old Dec 8, 2012 | 11:46 AM
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What crankshaft you suggest I change to? Thanks for the great advises!
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Old Dec 8, 2012 | 03:45 PM
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This guy built a really nice and very mild Darton sleeved 427. WCCH L92/LS3 heads and FAST. I think it made 577/530. Lots of good info in this thread.

https://ls1tech.com/forums/generatio...b-c-d-e-f.html
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Old Dec 9, 2012 | 09:01 AM
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Originally Posted by Blackpanther99
What crankshaft you suggest I change to? Thanks for the great advises!
Callies' Compstar cranks are great for anything under 1000whp, after that you may need a Magnum or DragonSlayer.
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Old Dec 9, 2012 | 03:14 PM
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Originally Posted by KCS
Callies' Compstar cranks are great for anything under 1000whp, after that you may need a Magnum or DragonSlayer.
Thanks bud, ill be looking towards on upgrading to that.
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