427 block that will respond best to boost?
427 block that will respond best to boost? I am looking for a 427 block that will respond very well to boost. Should I consider an iron block. I have a D1 procharger that I would like to use with the engine, but I am planning on getting a F1 procharger later. I am just doing some research right now, so give me all my options and all prices. I am planning to save up for a few years before I start this project, I don't want to buy parts from anyone right now.
How does the C5R block work with boost? I noticed someone has a f-1 with a C5R with cats, does anyone have any info on that setup?
Thanks for your help guys
How does the C5R block work with boost? I noticed someone has a f-1 with a C5R with cats, does anyone have any info on that setup?
Thanks for your help guys
price wise it would be (from cheapest to most expensive)
iron block
darton resleved ls1 alumin block
C5R aluminum block
if no cost was a concern id go with the C5r but the bare block is $5k
darton if your concerned about weight.
iron block if price is a concern.
for as what will hold up better dont really know, therotically the iron block will be stronger, not sure if anyone has gotten to the limit of the darton sleved block yet, the C5R's are pretty strong too.
iron block
darton resleved ls1 alumin block
C5R aluminum block
if no cost was a concern id go with the C5r but the bare block is $5k
darton if your concerned about weight.
iron block if price is a concern.
for as what will hold up better dont really know, therotically the iron block will be stronger, not sure if anyone has gotten to the limit of the darton sleved block yet, the C5R's are pretty strong too.
Bare C5R block is at least $6250 
I'd do a Darton MID (wet sleeve) it's sleeves are MUCH thicker than the C5R liners/sleeves. As long as the MID block is done correctly it is STRONGER than the C5R block for 1/2 the price.
I'd do a Darton MID (wet sleeve) it's sleeves are MUCH thicker than the C5R liners/sleeves. As long as the MID block is done correctly it is STRONGER than the C5R block for 1/2 the price.
Originally Posted by CANNIBAL
Bare C5R block is at least $6250
I'd do a Darton MID (wet sleeve) it's sleeves are MUCH thicker than the C5R liners/sleeves. As long as the MID block is done correctly it is STRONGER than the C5R block for 1/2 the price.
I'd do a Darton MID (wet sleeve) it's sleeves are MUCH thicker than the C5R liners/sleeves. As long as the MID block is done correctly it is STRONGER than the C5R block for 1/2 the price.
I guess the problem with the Alumi slevved block would be lifting the heads under alot of boost. Since the block is alumi, the head bolts holes will stretch and the heads will lift limiting u on how much boost u can run. So i would go with either C5R or LQ4-9 iron block. Good luck.
Originally Posted by 1dirtyZ
you will still lift the heads with an iron block. the problem is the head design.
I never heard of anyone lifting their heads on a iron block. Do u know any case? I would like to see how much boost it took to lift the heads on the iron block.
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TECH Apprentice
Joined: Jan 2004
Posts: 305
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HAha I luv these posts..
1.) You never really "lift the heads" per say. The cylinder head structure and head gasket design dictate how much and where the clamp load provided by the head bolts is distributed between the block and head. This "sealing pressure" provided by the system has to be greater than the applied forces its trying to contain. Once you start to boost an engine, you have significanty increased the combustion pressure its trying to contain in addition to adding a counter force onto the head surface itself (pushing againt it)to the allready deficient cylinder head.
2.) LS1/LS6 heads inhearantly have issues distributing ample load thru the coolant windows due to the lack of structure/material. Increasing the bolt load only adds local load at the base of each fastener (not at the combustion chamber). The head just continues to deflect (bend) with the increased load as the maximum load carrying capabilites have been met and exceeded.
3.) The worse heads are the 97/98 followed by early 99. Next would be revised mid year 99 and up ls1. LS6 are slight better than final revision LS1 heads. The best heads for structure are actually the 6.0 truck. With the hogged out bores which removed a lot of the head structure, GM significantly revised the struture inside the head to support the floating combusion chamber. You can actually feel the ribs/tie bars in the floor of the head if you probe inside the coolant passage.
4.) The block material has no impact on weather of not the head will seal for a givin condition on LSXs.
Hope this helps
Dave
1.) You never really "lift the heads" per say. The cylinder head structure and head gasket design dictate how much and where the clamp load provided by the head bolts is distributed between the block and head. This "sealing pressure" provided by the system has to be greater than the applied forces its trying to contain. Once you start to boost an engine, you have significanty increased the combustion pressure its trying to contain in addition to adding a counter force onto the head surface itself (pushing againt it)to the allready deficient cylinder head.
2.) LS1/LS6 heads inhearantly have issues distributing ample load thru the coolant windows due to the lack of structure/material. Increasing the bolt load only adds local load at the base of each fastener (not at the combustion chamber). The head just continues to deflect (bend) with the increased load as the maximum load carrying capabilites have been met and exceeded.
3.) The worse heads are the 97/98 followed by early 99. Next would be revised mid year 99 and up ls1. LS6 are slight better than final revision LS1 heads. The best heads for structure are actually the 6.0 truck. With the hogged out bores which removed a lot of the head structure, GM significantly revised the struture inside the head to support the floating combusion chamber. You can actually feel the ribs/tie bars in the floor of the head if you probe inside the coolant passage.
4.) The block material has no impact on weather of not the head will seal for a givin condition on LSXs.
Hope this helps
Dave
Originally Posted by 11 Bravo
The Darton block has stronger cylinder walls. It's fine under boost.
Here's some info from Steve (co-inventor of the Darton MID setup):
A block with MID sleeves and steel caps - studs, is more than equivalent in strength to the C5R block. Do not confuse the MID kit with a thin wall dry sleeve. The MID sleeves are almost a quarter inch thick at 4.125" bore.
The MID sleeves are considerably stronger than the sleeves in a C5R block. Same 130,000 psi tensile ductile iron as used by almost every top fuel and funny car team - Darton supplies most all the top runners. The only advantages the C5R block has over a standard block with MID sleeves are the steel main caps and studs. You can add these to any LS1 or LS6 block (not really necessary except for the highest out put engines). You will find that you can build two really strong MID blocks for the price of one C5R and have money left over.
lss1power. trust me iron blocks do lift the heads, i did on 2 different occasions.
99fbody, i totally agree with you: the heads kinda deform between the head bolts/studs, i guess a better head design would be the older small block chevy where you had 5 bolts per piston instead of the ls1's 4.
another thing you might look into that contributes to "lifting" the heads is the length of the bolts being used, the longer they are the "easier" they are to stretch because of different circumstances (i.e. load, thermal expansion etc.) thats why i think gm revised the 2004 blocks to only use "short" bolts/studs ( like the ones on either end of block) instead of the long ones, even though they where praising the benefits of using deeper bolt holes to reduce bore deformation.
99fbody, i totally agree with you: the heads kinda deform between the head bolts/studs, i guess a better head design would be the older small block chevy where you had 5 bolts per piston instead of the ls1's 4.
another thing you might look into that contributes to "lifting" the heads is the length of the bolts being used, the longer they are the "easier" they are to stretch because of different circumstances (i.e. load, thermal expansion etc.) thats why i think gm revised the 2004 blocks to only use "short" bolts/studs ( like the ones on either end of block) instead of the long ones, even though they where praising the benefits of using deeper bolt holes to reduce bore deformation.
Originally Posted by CANNIBAL
Exactly.
Here's some info from Steve (co-inventor of the Darton MID setup):
A block with MID sleeves and steel caps - studs, is more than equivalent in strength to the C5R block. Do not confuse the MID kit with a thin wall dry sleeve. The MID sleeves are almost a quarter inch thick at 4.125" bore.
The MID sleeves are considerably stronger than the sleeves in a C5R block. Same 130,000 psi tensile ductile iron as used by almost every top fuel and funny car team - Darton supplies most all the top runners. The only advantages the C5R block has over a standard block with MID sleeves are the steel main caps and studs. You can add these to any LS1 or LS6 block (not really necessary except for the highest out put engines). You will find that you can build two really strong MID blocks for the price of one C5R and have money left over.
Here's some info from Steve (co-inventor of the Darton MID setup):
A block with MID sleeves and steel caps - studs, is more than equivalent in strength to the C5R block. Do not confuse the MID kit with a thin wall dry sleeve. The MID sleeves are almost a quarter inch thick at 4.125" bore.
The MID sleeves are considerably stronger than the sleeves in a C5R block. Same 130,000 psi tensile ductile iron as used by almost every top fuel and funny car team - Darton supplies most all the top runners. The only advantages the C5R block has over a standard block with MID sleeves are the steel main caps and studs. You can add these to any LS1 or LS6 block (not really necessary except for the highest out put engines). You will find that you can build two really strong MID blocks for the price of one C5R and have money left over.
Originally Posted by BigD
Is the factory GM block made out of the same material as an C5R block? I don't believe so. Are the liners as long as a C5R blocks? I don't think so, you need as long as possibe liner for the piston skirts, epecially with a longer stroke. Also where is all the clamping load of the heads getting transfered to? It defiinetly isn't the block deck, has to be transfered somewhere. Just don't see a purpose built race block being less strong than a retro fit linered block.
Staging Lane
Joined: Jan 2004
Posts: 51
Likes: 0
From: Sterling Heights, MI
Originally Posted by 11 Bravo
Not trying to slam you, but you are totally wrong. First, Steve at Race Engine Development (a sponsor) probably knows 1000x more than you do about engine blocks. Second, I do not think he would lie, as you more or less have said. If you would look at a Darton block with your own eyes you would see where the clamping force of the head is transfered to. It's a non-issue. Darton wet sleeves have a problem with piston skirts? Where did you get that information? C5R blocks are made out of a different material? Where did you get that information? If you are going to state something you ought to give proof because this is a good site and people are easily misinformed.
The same would hold true of the C5R heads. Does someone want to say the street heads are just as good? I don't think so. Now the problem with the race heads are that the "cheap" intakes available for the production LS family of production engines will not fit these heads.
Originally Posted by Swifster
The C5R block is a no-holds-barred racing block. These were built with anticipated horsepower and torque loads of purpose-built race cars. You can modify an LS1 or LS6 block all you want and it's still a modified production street car block. Production pieces are made with compromises based on cost, production levels and profit margins. The C5R blocks were designed with no such constrants. This is why there is a $5000+ difference in the cost of a bare block between the two (not counting cost of installing new liners on a production block). If cost was no issue, I'd be using a C5R block. For me cost IS a factor so I'm using an LQ4 iron block with the truck heads.
The same would hold true of the C5R heads. Does someone want to say the street heads are just as good? I don't think so. Now the problem with the race heads are that the "cheap" intakes available for the production LS family of production engines will not fit these heads.
The same would hold true of the C5R heads. Does someone want to say the street heads are just as good? I don't think so. Now the problem with the race heads are that the "cheap" intakes available for the production LS family of production engines will not fit these heads.
C5R is a race block that is 2.5 times the hardness of a production block. The C5R blocks are in a class by themselves. Perhaps I should call the manufacturer of them and get him to give me a breakdown again (BigD knows him better than me).
Originally Posted by 11 Bravo
Not trying to slam you, but you are totally wrong. First, Steve at Race Engine Development (a sponsor) probably knows 1000x more than you do about engine blocks. Second, I do not think he would lie, as you more or less have said. If you would look at a Darton block with your own eyes you would see where the clamping force of the head is transfered to. It's a non-issue. Darton wet sleeves have a problem with piston skirts? Where did you get that information? C5R blocks are made out of a different material? Where did you get that information? If you are going to state something you ought to give proof because this is a good site and people are easily misinformed.
Also the blocks aren't expensive from GM because it isn't mass produced (they make about 150-200 a year FWIW). It is because the block is entirely outsourced. Every one has to get his cut including GM which is passed onto the consumer.
Answer me this, If the MID design is better why isn't the GM factory C5R Corvettes using them?
Last edited by BigD; Sep 2, 2004 at 06:47 AM.