HEY GRUMPYVETTE?
"I have mentioned that I would like to build a 383 for my car in the next cpl of years, while browsing around the other day I found an article about using a 400 block, going 60 over and stroking it to get what is for me the magic number of 427! My question is this, before I explore this any further, can LT1 heads, etc be used on a SB 400? Are the water and oil ports in the correct place? Do 400 blocks have 1 and 2 piece rear main seals? Has anyone here looked at this option? This is a project that is at least a year off for me so I am not in a hurry but the idea of a 427 vette really turns my crank! "
For the unaware.....
LT1 heads have the same bolt pattern (block to heads) as GEN1 blocks have always had, they however were designed to go on a reverse cooled engine, and part of the cooling system entailed two new coolant passages per head. These passages are what are now blocked off on those heads if used on the standard sbc block,If these are left unblocked, coolant will dump right into your lifter valley.
remember on an lt1 the coolant does not flow thru the intake manifold it goes out thru the water pump
can it be done? yes a good machine shop COULD make the necessary changes,
but welding up heads and making the required intake manifold modifications, gets damn expensive and the stock lt1 heads are not all that impressive,the ONLY justification for doing the swap is that the LT4 heads out flow the standard SBC O.E.M. heads and the LT4 heads can be fairly cheap, but what you save on the heads fast becomes a non-issue if you need to pay even more for the block,intake and head modifications required to get them to run on the earlier style blocks
but after talking with several people that have gone that route, in the past , the overwhelming consensus is that its an expensive waste of time for the results you get, and I know of NO ONE that would repeat the process.
the LT1 heads may be better than most of the O.E.M. factory heads but theres a FAR cheaper and FAR more practical approach that produces FAR better results, the better aftermarket heads of the standard design config far out flow stock lt1 heads, if your building a killer 427 sbc the newer AFR or DART PLATINUM HEADS (both in the 232-235cc port size)will far out pace the miserably restrictive LT1-LT4 heads
http://www.dartheads.com/ftp/Online%20P ... 0Sheet.htm
http://www.airflowresearch.com/eliminator235.php
thats to use a dart 4.125" bore aftermarket blocks, with the far thicker main caps webs and cylinder walls that are easily 100% stronger and significantly thicker in the stressed areas than the original 400 blocks, if your 100% determined to use the vortec port design then install the LARGE PORT VORTEC HEADS designed for the STANDARD SBC block configuration but with MUCH improved LT1]lt4 style ports that are near 210cc, that will easily allow you to build a 427 sbc that can EASILY exceed 600hp after some mild port work when matched to a killer roller cam in the 260 duration. on a 106-108 LSA range and a 427 displacement short block with about 11:1 compression and matching headers, intake and ignition mods
read thru the linked info
just keep in mind that if your really after max performance theres some trade offs with drive-ability, and if your running the large port vortec heads with a killer solid roller high compression 427, with the matched rear gearing stall speed and compression required , that's designed to be making over 600 hp your not building a true street drive-able combo
http://www.chevyhiperformance.com/techa ... index.html
http://www.streetlethal.net/camdata/
viewtopic.php?f=52&t=1834
viewtopic.php?f=69&t=1040&p=1943&hilit=206cc+vortec#p1943
building a 396 displacement lt4 style engine , that can be expected to produce 450-to-500 hp from the stock lt1 350 block modified with a stroker crank is done all the time with those heads. WITHOUT the need of use of a 400 block and its required mods
http://www.grandsportregistry.com/dyno.htm
http://www.purplesagetradingpost.com/sumner/techinfo/heads1.html
before you start thinking about a hybrid combo look at these
http://www.golenengineservice.com/html/lt1_lt4.html
I was asked," whats the difference between 2,4, and a splayed bolt block"
on a normal Chevy engine with 4 bolt main caps the caps look like this, notice the front cap is a two bolt main cap which is normal even on four bolt block where all the other caps have four bolts
on a two bolt block all the caps look like the front cap like this block below
racing blocks have SPLAYED 4 bolt main caps like this
which are even stronger
"I have mentioned that I would like to build a 383 for my car in the next cpl of years, while browsing around the other day I found an article about using a 400 block, going 60 over and stroking it to get what is for me the magic number of 427! My question is this, before I explore this any further, can LT1 heads, etc be used on a SB 400? Are the water and oil ports in the correct place? Do 400 blocks have 1 and 2 piece rear main seals? Has anyone here looked at this option? This is a project that is at least a year off for me so I am not in a hurry but the idea of a 427 vette really turns my crank! "
For the unaware.....
LT1 heads have the same bolt pattern (block to heads) as GEN1 blocks have always had, they however were designed to go on a reverse cooled engine, and part of the cooling system entailed two new coolant passages per head. These passages are what are now blocked off on those heads if used on the standard sbc block,If these are left unblocked, coolant will dump right into your lifter valley.
remember on an lt1 the coolant does not flow thru the intake manifold it goes out thru the water pump
can it be done? yes a good machine shop COULD make the necessary changes,
but welding up heads and making the required intake manifold modifications, gets damn expensive and the stock lt1 heads are not all that impressive,the ONLY justification for doing the swap is that the LT4 heads out flow the standard SBC O.E.M. heads and the LT4 heads can be fairly cheap, but what you save on the heads fast becomes a non-issue if you need to pay even more for the block,intake and head modifications required to get them to run on the earlier style blocks
but after talking with several people that have gone that route, in the past , the overwhelming consensus is that its an expensive waste of time for the results you get, and I know of NO ONE that would repeat the process.
the LT1 heads may be better than most of the O.E.M. factory heads but theres a FAR cheaper and FAR more practical approach that produces FAR better results, the better aftermarket heads of the standard design config far out flow stock lt1 heads, if your building a killer 427 sbc the newer AFR or DART PLATINUM HEADS (both in the 232-235cc port size)will far out pace the miserably restrictive LT1-LT4 heads
http://www.dartheads.com/ftp/Online%20P ... 0Sheet.htm
http://www.airflowresearch.com/eliminator235.php
thats to use a dart 4.125" bore aftermarket blocks, with the far thicker main caps webs and cylinder walls that are easily 100% stronger and significantly thicker in the stressed areas than the original 400 blocks, if your 100% determined to use the vortec port design then install the LARGE PORT VORTEC HEADS designed for the STANDARD SBC block configuration but with MUCH improved LT1]lt4 style ports that are near 210cc, that will easily allow you to build a 427 sbc that can EASILY exceed 600hp after some mild port work when matched to a killer roller cam in the 260 duration. on a 106-108 LSA range and a 427 displacement short block with about 11:1 compression and matching headers, intake and ignition mods
read thru the linked info
just keep in mind that if your really after max performance theres some trade offs with drive-ability, and if your running the large port vortec heads with a killer solid roller high compression 427, with the matched rear gearing stall speed and compression required , that's designed to be making over 600 hp your not building a true street drive-able combo
http://www.chevyhiperformance.com/techa ... index.html
http://www.streetlethal.net/camdata/
viewtopic.php?f=52&t=1834
viewtopic.php?f=69&t=1040&p=1943&hilit=206cc+vortec#p1943
building a 396 displacement lt4 style engine , that can be expected to produce 450-to-500 hp from the stock lt1 350 block modified with a stroker crank is done all the time with those heads. WITHOUT the need of use of a 400 block and its required mods
http://www.grandsportregistry.com/dyno.htm
http://www.purplesagetradingpost.com/sumner/techinfo/heads1.html
before you start thinking about a hybrid combo look at these
http://www.golenengineservice.com/html/lt1_lt4.html
I was asked," whats the difference between 2,4, and a splayed bolt block"
on a normal Chevy engine with 4 bolt main caps the caps look like this, notice the front cap is a two bolt main cap which is normal even on four bolt block where all the other caps have four bolts
on a two bolt block all the caps look like the front cap like this block below
racing blocks have SPLAYED 4 bolt main caps like this
which are even stronger