427 block with GPI Max Performance heads?

[Chris49066SS]

Originally Posted by l.o.d_yankee

$1450+shipping and tax. The website is being revamped right now. I found it hard to find the price myself.

#Fab5 ftw lol

[PumpinIron]

Originally Posted by lazerlemonta

The LS7 version is just around the corner. He will not find it yet........ Title of this thread is very misleading as well. You have an LS3 block and would be stroking it to 427 instead of 416. If you decided to purchase a LS7 block and build it you could then turn it 7800-8000. A stroker LS3 427 most are going to say 7200 to be safe.

I'll talk to GPI once I have the money, but it sounds like maybe a built LS7 block might be the ticket. I just want to reuse these GPI Max Performance LS7 heads if I can, as I'm sure you all know they didn't come cheap.

[PumpinIron]

Originally Posted by l.o.d_yankee

$1450+shipping and tax. The website is being revamped right now. I found it hard to find the price myself.

No kidding, I looked all over the website and wasn't able to find it!

Thanks!

[Katech_Zach]

They will fit fine. LS7 heads are interchangeable with LS3 heads from a bolt pattern perspective.

[christianchevell]

The deal is they are ls7 style small bore heads which means they will down size to fit a ls3 that's been stroked. A ls7 has a different bore than a stroked ls3 to get to its 427 cubes....also a ls7 block can only be overhoned .005 and therefore IMO and lots of others a real POS for future build perspective as just a overhone for new pistons and your there... brand new...you can if you researched find the ls7 engine for sale fairly cheap used because its just the parts and the life of the engine is very limited unfortunately....

That's the dirty little secret why the corvette guys are not all oh the ls7 zo6 is the greatest since sliced bread they ditch them....and go aftermarket block or ls3 even, and why the Corvette let the Camaro adopt the vaunted ls7 for the z-28 because its not like it was that great..... so it could rev higher with 1.8 rockers and a had more torque down low....

Me I thought it also insulting the ZL1 was not a 427 but then again......better off with out the ls7 to make one...because at least a ls3 can overhone .020, compare that to good old SBC/BBC iron blocks that you could overbore .060 for multiple rebuilds and yup its a total trash it block, I bought my new ls3 bare block for like $1400.... compare it to the ls7 block there is none in price and also BTW the ls7 heads at first were crap also until they got them right. The max heads will fit a stock ls3 block also its just not going to be as powerful of course as a stroked engine with larger cylinders to fill being that engines are basically a air pump.. and why a good FI small bore ls7 headed ls3 stroker is about as good as it gets as far as power output and longevity unless you want to get into aftermarket blocks and more $$$$$$

[lazerlemonta]

Originally Posted by christianchevell

The deal is they are ls7 style small bore heads which means they will down size to fit a ls3 that's been stroked. A ls7 has a different bore than a stroked ls3 to get to its 427 cubes....also a ls7 block can only be overhoned .005 and therefore IMO and lots of others a real POS for future build perspective as just a overhone for new pistons and your there... brand new...you can if you researched find the ls7 engine for sale fairly cheap used because its just the parts and the life of the engine is very limited unfortunately....

That's the dirty little secret why the corvette guys are not all oh the ls7 zo6 is the greatest since sliced bread they ditch them....and go aftermarket block or ls3 even, and why the Corvette let the Camaro adopt the vaunted ls7 for the z-28 because its not like it was that great..... so it could rev higher with 1.8 rockers and a had more torque down low....

Me I thought it also insulting the ZL1 was not a 427 but then again......better off with out the ls7 to make one...because at least a ls3 can overhone .020, compare that to good old SBC/BBC iron blocks that you could overbore .060 for multiple rebuilds and yup its a total trash it block, I bought my new ls3 bare block for like $1400.... compare it to the ls7 block there is none in price and also BTW the ls7 heads at first were crap also until they got them right. The max heads will fit a stock ls3 block also its just not going to be as powerful of course as a stroked engine with larger cylinders to fill being that engines are basically a air pump.. and why a good FI small bore ls7 headed ls3 stroker is about as good as it gets as far as power output and longevity unless you want to get into aftermarket blocks and more $$$$$$

My friends LS7 based 388 makes over 600 at the wheels using mast small bore LS3 heads and turns 8200RPM. LS7 block is not a bad piece. Think of it this way........... Unless a catastrophic failure how long would it take you to "wear" out the stock bore? I see a lot of people cringe from the LS7 block but for a basic build with out stressful parts it is a solid choice IMO. You can take a bolt on LS7 into the mid 550RWHP range along with similar torque. I have a pretty decent build to get to 560+ with my SBE LS3 and down almost 100 foot pounds to the LS7 bolt ons Just food for thought.

[sixty9fordkiller]

Originally Posted by PumpinIron

I recently ordered the GPI Max Performance package and MSD intake manifold.

In the near future I plan to do the bottom end. I'm well aware I can do a 416 block and keep the heads, but I'm curious as to whether I can do a 427 and retain my GPI Max Performance heads, or if that would require a different block and heads?

You'll have to forgive me since I'm new to Camaros (coming from BMW M cars) and LS engines in general.

Thanks!

If you're using an LS3 block, you can stroke and bore whatever you want on it and the GPI MAX package will work. Nothing changes for the top end


If you are stroking an LS3 to get 427 cubes out of it, the piston skirts are gonna come way down into the crankcase are. piston speed is gonna be through the roof. not sure if its a good combo if you wanna spin it too high

[KW Baraka]

Originally Posted by PumpinIron

Yes, I have the GPI Max Performance heads (modified LS7 heads as I understand it) on my LS3. I'm wanting to stroke the LS3 block and turn it into a 427ci......

The LS3 427ci.....IS NOT......the same as the GM LS7 427ci.

That said, your LS7 heads might fit the LS3 but you'll want to have the cylinders bored to at least 4.07". And even then, the tightness of the bores will not allow you to take full advantage of the LS7 heads flow capabilities.

Bottom line, you will not get the full benefits of the LS7 Max Performance kit with the LS3 block. Plain and simple.

KW

[PumpinIron]

Originally Posted by sixty9fordkiller

If you're using an LS3 block, you can stroke and bore whatever you want on it and the GPI MAX package will work. Nothing changes for the top end


If you are stroking an LS3 to get 427 cubes out of it, the piston skirts are gonna come way down into the crankcase are. piston speed is gonna be through the roof. not sure if its a good combo if you wanna spin it too high

Do you know what the LS3 bottom end can safely be bored / stroked to?

I suppose I could just ask GPI when the time comes to place the order, but I'm just curious in the meantime.

[PumpinIron]

Originally Posted by KW Baraka

The LS3 427ci.....IS NOT......the same as the GM LS7 427ci.

That said, your LS7 heads might fit the LS3 but you'll want to have the cylinders bored to at least 4.07". And even then, the tightness of the bores will not allow you to take full advantage of the LS7 heads flow capabilities.

Bottom line, you will not get the full benefits of the LS7 Max Performance kit with the LS3 block. Plain and simple.

KW

Got it. I'll have to pick GPIs brain when the time comes.

Since I have these GPI Max Performance heads, the next step would be to build the bottom end. I'm just not sure what that entails (i.e. boring and stroking the stock LS3 block, getting an entirely new block, etc.).

It would be a shame to have to just ditch the heads when it comes time for a new bottom end, you know?

[christianchevell]

You wont have to ditch the heads..... And if you price out a ls7 versus a stroked ls3 you will see the large disparity in price is big time, I would say a 418 some day will be fine as most do that /416 what ever and yes they make custom pistons just for stroking now adays……. Used ls7 like a said can be had for cheap....the blocks a boat anchor used.....usually.