I'm looking to price out how much it would cost to build a 427 like the LS7. I was wondering if it would be better to drop the extra cash for an LS7 block or just get the LSX block and have it bored out? Also where would you recommend to pick up one of these blocks at? Thanks for any help and advice

 

What are your plans for it? Honestly, I would build a 402 and use the savings elsewhere. If money is no object, the LSX block is stronger than the LS7 block...

 

LSX should be much better over all unless i am mistaken. It's what i would build, put it that way.

 

if you're weight conscious, the ls7. If you want a block that will take pretty much everything you'll throw at it. the LSX. ls7 block is aluminum, lsx is iron.

 

Personally, id go LSX.

We have 3 or 4 LS7 blocks in stock.

 

And on a related note, if your plans include any serious forced induction, an iron block will give you a much better foundation.

 

LS7 is a bit of an orphan in which only LS7 related parts work with it. Not sure of all the differences but theres a hella lot more options for building an LSX than an LS7 so LSX gets my vote too.

How much power do you need though? Boosted 6.0L gets 600 rwhp pretty easy

 

Generally, if someone is running enough power that an LS7 block's strength is a consideration, then their going to be using a custom rotating assembly, oil system etc.

My boss's '03 Z06, has a LS7 block, it makes 954rwhp with a TTIX Turbo kit, AFR Heads etc. Block is taking the power without even breaking a sweat.

For an idea of what the GM aluminum blocks can take, our tuner's 02 Z06 has a Vortech V-7 YSi on his 402 (LS2 block) making 929hp @ the wheels. Same deal, motor is taking the power without breakin a sweat.

Can guarentee a 6.0 iron block will take the same power levels and more.

IMO, LS7 block is a chunck of money, thats un nessicary unless you really need to knock off the 100lbs. Same with the warhawk blocks, not worth it IMO.

If your aiming for around 1000hp @ the crank, id go for a 6.0L iron block and poke/stroke it to a 408. A Procharger F-1A will take that over 800rwhp, and if you get really ambigious, a F-1R will haul over 1000rwhp.