lt1 vs lt4 corvette engine parts differences & useful links

failing to read through the links and sub-links on this web site is always a bad idea

http://www.grandsportregistry.com/lt1vslt4.htm

http://www.enginebuildermag.com/1999/09/rebuilding-the-chevrolet-lt1-engine-2/

http://www.hotrod.com/articles/ccrp-0909-lt1-engine-build/

https://www.nookandtranny.com/Info_LT1.html

http://www.superchevy.com/how-to/0908gmhtp-lt1-cylinder-head-comparison/

http://www.airflowresearch.com/chevy/sbc-eliminator-23-lt1-cylinder-head/

http://www.superchevy.com/how-to/project-cars/sucp-0008-chevy-lt1-engine-build/

http://www.superchevy.com/how-to/4496-500-hp-na-chevrolet-lt1-engine/

http://www.superchevy.com/how-to/en...t-1-aiming-for-600-plus-hp-with-a-396-gen-ii/

http://www.hotrod.com/articles/ccrp-0801-gen-ii-chevy-small-block-engine/

http://www.superchevy.com/how-to/0506htp-lt1-high-mileage-reliable-build/

http://www.superchevy.com/how-to/en...o-testing-7-popular-lt1-engine-modifications/

http://www.enginelabs.com/news/video-383ci-stroker-lt1-makes-a-strong-case-for-gen-ii-engines/

http://garage.grumpysperformance.com/index.php?threads/opti-crap-ignition-rebuild.758/

http://garage.grumpysperformance.com/index.php?threads/optispark-ignition-info.628/#post-1086

https://play.google.com/store/books...O1&gclid=COCO3azk4tECFSi2gQodNikO4A&gclsrc=ds

https://play.google.com/store/books...d_LT1_LT4_Small_Block_Chevy_E?id=sfCQEB3bLqYC



one of the major reasons for the 2nd generation SBC or LT1/lt4 was the goal of reducing exhaust emissions by allowing leaner fuel/air mixtures and higher compression ratios to be used.
leaner F/A ratio's reduce emissions and higher compression theoretically boosts potential torque.
if you look at the LT1-LT4 engines the basic difference from the earlier first generation sbc engines is that the block was re-designed to use a reverse flow direction on coolant flow to feed cooler temperature coolant through the cylinder heads , and return the coolant through the block rather than the earlier SBC routing of coolant through the block and up into the cylinder heads and back out the intake manifold T-stat housing, this was done to reduce the cylinder head operating temps, as reducing the combustion chamber temps , this results in the engine being able to use higher compression before the engine enters the range where detonation in the cylinders can cause mechanical damage to the pistons and rings with any octane level of fuel.
the next change was in the ignition or spark control,
the OPTI-SPARK at least in theory has less likely to be subject to spark scatter.
the redesigned "VORTEC STYLE HEART SHAPED COMBUSTION CHAMBER " use in the LT1-4 series heads increased the engine fuel/air compressed gases,combustion speed, this allows less wasted energy because you don,t need to ignite the compressed fuel/air mix so far in advance of TDC.
remember that the first gen SBC was built when carburetors were common and emission testing was not required, the LT1/LT4 was designed with taller ports and faster air flow speeds , in mind ,as direct port fuel injection was the primary fuel supply system, being used.


http://garage.grumpysperformance.co...temps-detonation-resistance.12842/#post-66668

http://garage.grumpysperformance.co...flow-rates-and-heat-transfer.9880/#post-57638

http://garage.grumpysperformance.co...octane-for-compression-ratio.2718/#post-68131

http://garage.grumpysperformance.co...temps-detonation-resistance.12842/#post-66660

http://garage.grumpysperformance.co...cranking-pressure-calculator.4458/#post-61262

http://garage.grumpysperformance.co...compression-torque-dcr.1070/page-2#post-52809

http://garage.grumpysperformance.co...w-camaro-impala-part-numbers.9609/#post-35573

http://garage.grumpysperformance.co...t-to-get-1996-vette-running.12254/#post-59959

http://www.enginebuildermag.com/1999/09/rebuilding-the-chevrolet-lt1-engine-2/

http://garage.grumpysperformance.com/index.php?threads/optispark-ignition-info.628/#post-52417

http://garage.grumpysperformance.com/index.php?threads/optispark-rebuild-info.369/#post-451

http://garage.grumpysperformance.co...shaft-position-sensor-p0336.10378/#post-42861


http://garage.grumpysperformance.co...t1-fuel-system-trouble-shooting.595/#post-782

http://garage.grumpysperformance.com/index.php?threads/92lt1-runs-like-crap.10370/#post-42739

http://garage.grumpysperformance.co...elated-part-numbers-and-info.6224/#post-19467

http://garage.grumpysperformance.co...ap-and-rotor-or-compete-unit.7826/#post-26965

http://www.superchevy.com/how-to/0310htp-lt1-ignition-system-understanding-modifying/

http://www.dynaspark.net/

http://www.superchevy.com/how-to/16758/
if you have a REVERSE FLOW BLOCK
your very likely looking at an LT1/lt4 style engine

pictures difference between lt1 and gen1 chevy block
by Aron213 » Wed Apr 13, 2005 5:44 pm

Ok, maybe some of you will now understand what angles and spacing I am talking about when I say you can and can not do somethings. I didnt have a set of Vortec 350 heads laying around so I used a set of 305 heads which doesnt use the same intake design(actually they are still swirl port junkers) but does use the same bolt pattern.

Pic one, is a Lt1 head, notice that the bolt angle is not flush with the intake face.



Now here is the same head next to a standard SBC head, notice the bolt angle as compared to the SBC gen 1 head, also notice the spacing is different between the two heads. LT1 head is on the left, SBC GEN1 head is on the right. Also notice there is no water jacket on the intake face of the LT1



Here is a SBC GEN1 head next to the LT1 head..This is the deck surface, notice all the water jacket openings are different..SBC Gen1 head is on the left, LT1 on the right




http://h-body.org/people/projects/building_lt1/lt1 info.html


Now there two are for the vortec head, notice that the bolts are even more of an angle than the LT1, when you bolt this intake on, the bolts are facing straight down, also notice there are only 4 bolts per head on the intake, there isnt any bolt holes in the middle





http://www.corvetteactioncenter.com/specs/c4/1996/lt1lt4.html

the later GEN2 LT!/LT4 reverse coolant flow block (ABOVE) differs from the first gen SBC
the LT1/LT4 second gen SBC engine was standard in the 1992-1996 corvette


look carefully at the first gen SBC block below









http://garage.grumpysperformance.co...ts-differences-useful-links.13141/#post-68540
http://garage.grumpysperformance.co...ts-differences-useful-links.13141/#post-68540
1995-96 corvette cooling hoses

BTW heres some common LT1 part numbers


Ignition:
1993-1994 optispark (non-vented style, spline driven) 10457702
1995-1997 optispark (vented style, cam dowel driven) 1104032
1995-1997 vented optispark vacuum hoses 12555323
1993-1994 optispark electrical harness 12106559
1995-1997 optispark electrical harness 12130319
1993 ignition coil 1115315
1994-1995 ignition coil 10477208
1996-1997 ignition coil 10489421
1993 ignition control module 10483131
1994-1995 ignition control module 10483139
1996-1997 ignition control module 10482803

Camshaft/Valvetrain LT4 valve springs (set of 16) 12495494
LT4 Valve spring (1) 12551483
LT4 extreme duty timing set 12370835
LT4 Hotcam
(CRANE CAMS USED TO SUPPLY MANY G.M.PERFORMANCE CAMS,
this is no longer true and QUALITY has dropped off noticeably by who ever is currently supplying the cams)
LT4 1.6 roller rocker arm (1) 12557779
1993-1994 front cover (includes round seals) 12551636
1995 front cover (includes round seals) 12552426
1996-1997 front cover (includes round seals) 12552427
1993-1994 front cover opti seal 10128317
1995-1997 front cover opti seal 12552428
1993-1997 front cover crank seal 10128316
1993-1997 front cover water pump seal 10217886
1993-1997 front cover gasket 10128293

General Engine:
LT4 heads 12555332
LT4 Intake Manifold 12550630

Misc
F-body a/c delete pulley 10115875
1993-1997 water pump 12527741
1993-1997 water pump coupling 10128334
1993-1994 1LE intake elbow (no vent hole for opti) 25147210
1995-1997 1LE intake elbow (for vented opti) 25147187
1994-1997 front flexible fuel supply lines 10258441

PCM Related
1993-1995 knock sensor 10456126
1996-1997 knock sensor 10456287
LT1 Knock Module 94-95 OBD1 16217700
LT1 Knock Module 96-97 OBD2 16214661
LT4 Knock Module 96-97 OBD2 16214681

Head Gasket Thickness
Stock gasket = 0.040
Fel Pro 1074 = 0.039
Impala = 0.029
Mr Gasket 5716 = 0.026

12561388 Main Bearing Cap Bolt Outer 10
3877669 Main Bearing Cap Bolt Inner 6
12561389 Main Bearing Cap Stud Inner 3
9442946 Main Bearing Cap Nut For Windage Tray 1
12453170 Camshaft Bearing—Camshaft #1 1
12453171 Camshaft Bearing—Camshaft #2 1
12453172 Camshaft Bearing—Camshaft #3, 4 2
10241154 Camshaft Plug—Rear 1
88891749 Freeze Plug, Cup—Brass 41.1mm 8
10120990 Main Bearing (Std) #1, 2, 3, 4 (All Small Blocks Except 383) 4
10120993 Main Bearing (Std) Rear (All Small Blocks Except 383) 1
1453658 Transmission Dowel Pin 5/8″ X 1 3/16″ 2
12554553 Front Dowelpin 1/4″ X 5/8″ 2
585927 Dowel Pin 5/16″ X 9/16″ 4
14081701 1/4″ Pipe Plug (Thread Socket Head) 4
14091563 Oil Galley, Steel Cup Plug (.476″) 4
9441003 Rear Seal Housing Locator Pin 7/16″ X 9/16″ 1
14084945 Block Drain Plug (1/4-18 X .56) Threaded 2
14088556 Rear Seal Retainer 1
10088158 Rear Crank Seal 1-Pc Style 1
14080362 Oil Pan Stud—Outboard 1
12555771 Rear Adapter Gasket to Block 1
14101058 Adapter Stud 2
14088561 Adapter Bolt—Torx Upper 1
9439915 Hex Nut, Adapter To Stud 1/4-20 X .234 1
14088562 Adapter Bolt, Torx Thru Loc Pin 1/4-20 X .75
10121044 Rear Seal (2-Piece Seal Design) 1
12513961 Front Cover, Sheet Metal With Welded Pointer 1
10108435 Front Cover Gasket—Sheet Metal Cover 1
10243247 Front Crank Seal—Sheet Metal Cover 1
12562818 Cover, Engine Front w/o Pointer ZZ4 Design Engines 1
10228655 Front Crank Seal 1
9439930 Front Cover Bolt 10
10213293 Front Cover Bolt 6
12551135 Front Cover Bolt 2
10213294 Eng Frt Cover Bolt Grommet 8
14090911 Plug (3/8-18 Threaded) ar
10168527 Head Bolt—Short 4
10168526 Head Head—Medium 20
10168525 Head Head—Long 4
10089648 Rocker Arm—w/Nut & Ball (Use With All Steel Rockers) ar
10088128 Camamsft Retainer 1st Des 3.620 Bolt Pattern 1
10168501 Camshaft Retainer 2nd Des 3.294 Bolt Pattern 1
14093637 Camshaft Bolt Retainer (Torx) 2
12554553 Camshaft Sprocket Locator Pin To Cam 1/4 X 5/8 1
9424877 Camshaft Bolt Sprocket 5/16-18 X 3/4 300m 3
10108688 Connecting Rod—All Except 383 Engines ar
461372 Connecting Rod Bolt—All Except 383 Engines ar
225854 Connecting Rod Nut—All Except 383 Engines ar
12523924 Connecting Rod Bearing (Std) Except 383 Engine ar
10046031 Flywheel Locator Pin 7/16 X 7/8 1
14061685 Clutch Pilot Bearing All With Manual Trans. 1
106751 Damper Key—Front Of Crankshaft (Woodruff) 1
3754587 Water Pump Gasket 2
9442012 Water Pump Bolts 3/8-16/ 2 1/4 4
14088753 Water Outlet 1
10198997 Water Outlet Bolts 2
10105135 Water Outlet Gasket 1
10207373 Thermostat, 195 Deg 1
10202456 Thermostat, 180 Deg 1
10108676 Oil Pan Gasket (1-Pc Des) 1
11518377 Oil Pan Drain Plug 12mm 1
3536966 Oil Pan Drain Plug O-ring Seal 1
3921988 Oil Pan Drain Plug, 1/2 1
14090908 Oil Pan Drain Plug Gasket 1
12553058 Oil Pan Reinforcement LH 1
12553059 Oil Pan Reinforcement RH 1
9440033 Oil Pan Bolt 1/4-20 X 5/8 14
12338130 Oil Pan Nut 5/16-18 2
9424877 Oil Pan Bolt 5/16-18 X 3/4 2
12551154 Oil Tube Indicator 1
12551144 Oil Tube Indicator 1
3952301 Oil Filter Adapter w/Bypass Valve
3951644 Oil Filter Adapter Bolt 5/16-18 X 1 1/8 2
3764554 Oil Pump Shaft Retainer (Nylon) 1
12525810 Intake Manifold Gaskert Set (For ZZ4 Engines) 1
89017465 Intake Manifold Gasket (For Vortec Design Heads) 1
12550027 Bolt, Intake Manifold (All With Vortec Design Heads) 8
88891769 Bolt, Intake (3/8-16 X 1 1/2 ) ZZ4 Design Engines 4
14091544 Bolt, Intake (3/8-16 X 1 1/8 ) ZZ4 Design Engines 4
9439918 Bolt, Intake (3/8-16 X 1 3/8 ) ZZ4 Design Engines 4
6269414 Manifold, Egr Cover, ZZ4 Engine 1
12554530 EGR Gasket ZZ4 Engine 1
9442184 EGR Cover Bolt T/w 9439571 Washer 2
14094792 Manifold, Choke Cover ZZ4 Engine 1
14096848 Manifold Choke Cover Gasket ZZ4 Engine 1
14094069 Fuel Pump Block Off Plate 1
12560223 Fuel Pump Cover Gasket 1
3719599 Fuel Pump Adapter Plate 1
9440033 Bolts, Fuel Pump 1/4-20 X 5/8 2
9442963 Bolts, Fuel Pump 3/8-16 X .3/4 2
3704817 Fuel Pump Push Rod 1

http://www.superchevy.com/how-to/engines-drivetrain/1705-gen-ii-lt1-engine-build/

http://www.superchevy.com/how-to/engines-drivetrain/closer-look-chevy-lt-engine/

http://garage.grumpysperformance.com/index.php?threads/l98-lt1-head-swap.13960/#post-71183


CROSSFIRE



LT1/LT4


LT5



L98