1969 350 300hp
03-08-2006, 04:23 PM
#21
Le Mans Master
Originally Posted by gonzo14
I have a 68 300 hp numbers matching and I can attest, that the heads and block are identical to the 350 hp version. I read on this and found it to be only the cam, carb and manifold that are different, both have identical torque values (360 ft lbs)
03-08-2006, 04:26 PM
#22
Originally Posted by Oldguard 7
The LT-1 engine was a monster in it's day!!!!
03-08-2006, 05:01 PM
#23
Instructor
Originally Posted by edheinrich
73 and 74 specs, the others are also on the site: http://www.nastyz28.com/camaro/z28l82.html
Audie
03-08-2006, 06:42 PM
#24
Le Mans Master
Originally Posted by audiec
I have been trying to pull together the informaiton on the L46 350\350.
I have never read about the high tin block before, can this be verified?
Also have not been able to verify that the L46 186 heads had pressed in studs vs screwed in w\guide plates? And the machined combustion chamber relief, can this be verified?
I have never found the specs on the rods other than the forged "pink rods" were used. Part number?
I am also still looking for the piston part number and dome spec?
If we can verify this I will post what I have compiled...
Audie
I have never read about the high tin block before, can this be verified?
Also have not been able to verify that the L46 186 heads had pressed in studs vs screwed in w\guide plates? And the machined combustion chamber relief, can this be verified?
I have never found the specs on the rods other than the forged "pink rods" were used. Part number?
I am also still looking for the piston part number and dome spec?
If we can verify this I will post what I have compiled...
Audie
There were no screw-in studs on anything before 1970 so they were not a requirement for the 69 L-46 in the original configuration. Might have been used in '70 and up though as they are included with L-82 for sure. it just makes sense that they would be included during L-46 production for '70 and up. Not a big deal as they are easy to add.
The factory 64cc heads such as the "186" that have the big valves (from the factory) will definately have the chamber unshrouding where the small valve versions of the same head casting will not. The later smog open chamber heads do not have unshrouded chambers.
I ain't gonna BS you about the rest cuz I dun-no.
-Mark.
03-09-2006, 04:09 PM
#25
Instructor
L46-350cid\350hp Specifications (still in draft)
RPO L46 = 350cid\350hp (Hi Per V8)
Brake horsepower: * 350 hp (261 kW) @ 5600 RPM (See note 1)
Torque: * 380 lb-ft @ 3800 RPM
Bottom end: + Good for 6500K RPM
Block: ** 4-bolt main, +++ #3970010 (+ possibly high Nickel/Tin content
Iron 010/020 numbers under timing cover and other locations)
Camshaft: * Hydraulic Flat Tappet (See note 2)
Valve lifters: * Flat Tappet - Hydraulic
Compression ratio: * 11.0:1
Heads: ** 2.02\1.6 Valves (See note 3)
Crankshaft: ** Forged steel (See note 4)
Rods: ** Hardened "pink" rods (See note 5)
Pistons: ** TRW domed, forged, and pressed pins (See note 6)
Oil pan: + Windage tray
Harmonic Balancer: +++ 8” non-finned, 6 ¼” Hub, 8” diameter, 1 ¾” thick
Intake Manifold: * Cast Iron Spread bore (See note 7)
Carburetor: * Quadrajet, 4-bbl (See note 8)
Exhaust: ** 2" Exhaust pipe with Walker mufflers
Exhaust Manifolds: ** RH - #3932465
++ ** LH - #3846559
Tachometer: * 6000-RPM Redline
Air Filter: ** Open element air filter (Early), Dual Snorkel (Late)
Water Pump: ** #3782608
Ignition: + Distributor w\points & HP curve
** #1111491
** #1111493
** #1112021
Alternator: ** #1100900
Transmission: ** Main case #3925661, Extension Housing #3857584, Side
#3952648 (Right side of maincase, just in front of extension
housing)
Rear End: **** CAM=3.36:1
**** CAT=3.08:1
Radiator: **+ Copper with plastic fan shroud and no overflow tank.
Console Data Plate: * 350cid, 350hp, 380 lb-ft Torque (L46)
Valve Covers: ** Aluminum, 7-finned, with twist on cap and each side vents
Notes:
1. + A 1966 L79 (327/350hp) with a fresh stock rebuild run on a chassis dyno, and his best was 238 hp at the rear wheels.
2. * Part Number 3896962, Hydraulic, 69-81 L-46 and L-82 Corvette cam, moderate torque, excellent power, casting #3896964. The casting symbol is a vertical diamond.
* Duration at lash point: (I:312\E:312)
* Duration at .050” Tappet Lift: (I:222\E:222)
* Maximum Lift with 1.5:1 Rocker Ratio: (I:.450”\E:460”)
* Valve Lash: Zero\Zero
* Lobe Centerlines: 114
3. Heads – ** 300hp engines did not get screw in studs or guide plates, 350 hp did.
** Casting #3927186, 63.305cc combustion chamber. 2.02 Heads got screw in studs, and guide plates. Casting #3991492 may appear on this part after 4/5/71. Casting #3947041 head was possibly used interchangeable with this head through 1969 and 1970 production. Small camel humps casting symbol.
** Casting #3927187, 63.305cc combustion chamber. Casting #3927186 may appear on this part until 10/9/70. After this date #3991492 may appear. Casting #3947041 head was possibly used interchangeable with this head through 1969 and 1970 production. All #3927187 heads have 2.02\1.60 valves. Casting symbol is small camel humps.
** Casting #3947041, 63.995 or 63.305 combustion chamber. 1970 had 2.02/1.60 valves, used as interchange on some models with #3927186 and 3927187 heads. Casting symbol is a slanted triangle.
+ The 69 L46's had pressed in rocker studs while the 1970 and later L46's and LT1's got the better screw in variety. 1970 did not get push rod guide plates. Uses steel shim head gasket.
+ Heads have machined combustion chamber relief (un-shrouded) for flow and 2.02/1.6 valves, pressed in rocker studs.
+ There were no screw-in studs on anything before 1970 so they were not a requirement for the 69 L-46 in the original configuration. Might have been used in '70 and up though as they are included with L-82 for sure. It just makes sense that they would be included during L-46 production for '70 and up. Not a big deal as they are easy to add.
+ The factory 64cc heads such as the "186" that have the big valves (from the factory) will definitely have the chamber un-shrouding where the small valve versions of the same head casting will not. The later smog open chamber heads do not have un-shrouded chambers.
4. ***** Large journal (2.10"\2.450"), stroke 3.484, casting number 3941182 or **3941188.
5. ** Rods are forged, shot-peened, magnafluxed, and heat treated to 500 degrees for ten or more hours Introduced in 1970 as a pressed-pin design with large rod diameter journal and high-rpm rod bolts used in the 302cid.
6. + Part numbers are stamped into the top. Standard piston is 3942541, the +.001 was GM #3942542, and the +.030 was GM #3942543.
7. ** Large raised letter S on underside, and oil splash shield, casting #3965577
8. ** 1969, Model 4MV, 7029207, ST
** 1970, Model 4MV, 7040207, ST non-CA
** 1970, Model 4MV, 7040507, ST-CA
* Source = GMC
** Source = Corvettes by the numbers
*** Source = Corvette Black Book
**** Source = 1970 Corvette Registry
***** Source = Mortec.com
+ Quote from Corvette Forum member
++ Source = NastyZ28.com
+++ Source = Chevrolet Small-block V8 Guide
++++ Unverified
Brake horsepower: * 350 hp (261 kW) @ 5600 RPM (See note 1)
Torque: * 380 lb-ft @ 3800 RPM
Bottom end: + Good for 6500K RPM
Block: ** 4-bolt main, +++ #3970010 (+ possibly high Nickel/Tin content
Iron 010/020 numbers under timing cover and other locations)
Camshaft: * Hydraulic Flat Tappet (See note 2)
Valve lifters: * Flat Tappet - Hydraulic
Compression ratio: * 11.0:1
Heads: ** 2.02\1.6 Valves (See note 3)
Crankshaft: ** Forged steel (See note 4)
Rods: ** Hardened "pink" rods (See note 5)
Pistons: ** TRW domed, forged, and pressed pins (See note 6)
Oil pan: + Windage tray
Harmonic Balancer: +++ 8” non-finned, 6 ¼” Hub, 8” diameter, 1 ¾” thick
Intake Manifold: * Cast Iron Spread bore (See note 7)
Carburetor: * Quadrajet, 4-bbl (See note 8)
Exhaust: ** 2" Exhaust pipe with Walker mufflers
Exhaust Manifolds: ** RH - #3932465
++ ** LH - #3846559
Tachometer: * 6000-RPM Redline
Air Filter: ** Open element air filter (Early), Dual Snorkel (Late)
Water Pump: ** #3782608
Ignition: + Distributor w\points & HP curve
** #1111491
** #1111493
** #1112021
Alternator: ** #1100900
Transmission: ** Main case #3925661, Extension Housing #3857584, Side
#3952648 (Right side of maincase, just in front of extension
housing)
Rear End: **** CAM=3.36:1
**** CAT=3.08:1
Radiator: **+ Copper with plastic fan shroud and no overflow tank.
Console Data Plate: * 350cid, 350hp, 380 lb-ft Torque (L46)
Valve Covers: ** Aluminum, 7-finned, with twist on cap and each side vents
Notes:
1. + A 1966 L79 (327/350hp) with a fresh stock rebuild run on a chassis dyno, and his best was 238 hp at the rear wheels.
2. * Part Number 3896962, Hydraulic, 69-81 L-46 and L-82 Corvette cam, moderate torque, excellent power, casting #3896964. The casting symbol is a vertical diamond.
* Duration at lash point: (I:312\E:312)
* Duration at .050” Tappet Lift: (I:222\E:222)
* Maximum Lift with 1.5:1 Rocker Ratio: (I:.450”\E:460”)
* Valve Lash: Zero\Zero
* Lobe Centerlines: 114
3. Heads – ** 300hp engines did not get screw in studs or guide plates, 350 hp did.
** Casting #3927186, 63.305cc combustion chamber. 2.02 Heads got screw in studs, and guide plates. Casting #3991492 may appear on this part after 4/5/71. Casting #3947041 head was possibly used interchangeable with this head through 1969 and 1970 production. Small camel humps casting symbol.
** Casting #3927187, 63.305cc combustion chamber. Casting #3927186 may appear on this part until 10/9/70. After this date #3991492 may appear. Casting #3947041 head was possibly used interchangeable with this head through 1969 and 1970 production. All #3927187 heads have 2.02\1.60 valves. Casting symbol is small camel humps.
** Casting #3947041, 63.995 or 63.305 combustion chamber. 1970 had 2.02/1.60 valves, used as interchange on some models with #3927186 and 3927187 heads. Casting symbol is a slanted triangle.
+ The 69 L46's had pressed in rocker studs while the 1970 and later L46's and LT1's got the better screw in variety. 1970 did not get push rod guide plates. Uses steel shim head gasket.
+ Heads have machined combustion chamber relief (un-shrouded) for flow and 2.02/1.6 valves, pressed in rocker studs.
+ There were no screw-in studs on anything before 1970 so they were not a requirement for the 69 L-46 in the original configuration. Might have been used in '70 and up though as they are included with L-82 for sure. It just makes sense that they would be included during L-46 production for '70 and up. Not a big deal as they are easy to add.
+ The factory 64cc heads such as the "186" that have the big valves (from the factory) will definitely have the chamber un-shrouding where the small valve versions of the same head casting will not. The later smog open chamber heads do not have un-shrouded chambers.
4. ***** Large journal (2.10"\2.450"), stroke 3.484, casting number 3941182 or **3941188.
5. ** Rods are forged, shot-peened, magnafluxed, and heat treated to 500 degrees for ten or more hours Introduced in 1970 as a pressed-pin design with large rod diameter journal and high-rpm rod bolts used in the 302cid.
6. + Part numbers are stamped into the top. Standard piston is 3942541, the +.001 was GM #3942542, and the +.030 was GM #3942543.
7. ** Large raised letter S on underside, and oil splash shield, casting #3965577
8. ** 1969, Model 4MV, 7029207, ST
** 1970, Model 4MV, 7040207, ST non-CA
** 1970, Model 4MV, 7040507, ST-CA
* Source = GMC
** Source = Corvettes by the numbers
*** Source = Corvette Black Book
**** Source = 1970 Corvette Registry
***** Source = Mortec.com
+ Quote from Corvette Forum member
++ Source = NastyZ28.com
+++ Source = Chevrolet Small-block V8 Guide
++++ Unverified
(no offence) 
03-17-2006, 03:39 PM
#29
Drifting
Member Since: Mar 2003
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St. Jude Donor '05-'06
Well I have a 1970 300HP car. I tried to find all this out two years ago. Without spending big bucks I modded it as close to the L46 350HP motor as I could. I changed the following:
1. 2.02/1.92 valves in head, deshrouded valves/port and polish, screw in studs.
2. L46/L82 cam
3. Bigger exhasut. Stock exhaust is 2*1/4, the L46s came with 2&1/2 but it left the engine at 2&1/4 and then about 3 inches later goes to 2&1/2 with a welded flange.
4. Carb jetting.
5. LARS modded distributor for HP curve
6. Finned valve covers
To my knowledge my only shortcoming is the crank/rods/pistons in my engine. Hence my redline is 5300ish. My engine tops out in the 4000s. I probably need to look at flows to examine if my exhaust/intake is choking my engine.
I managed 228RWHP / 290 RWTQ after my rebuild. This is pretty close to the 327 below. I should be closer to 250-260RWHP and 320RWTQ with my engine being a 366 now.
From above:
Notes:
1. + A 1966 L79 (327/350hp) with a fresh stock rebuild run on a chassis dyno, and his best was 238 hp at the rear wheels.
1. 2.02/1.92 valves in head, deshrouded valves/port and polish, screw in studs.
2. L46/L82 cam
3. Bigger exhasut. Stock exhaust is 2*1/4, the L46s came with 2&1/2 but it left the engine at 2&1/4 and then about 3 inches later goes to 2&1/2 with a welded flange.
4. Carb jetting.
5. LARS modded distributor for HP curve
6. Finned valve covers
To my knowledge my only shortcoming is the crank/rods/pistons in my engine. Hence my redline is 5300ish. My engine tops out in the 4000s. I probably need to look at flows to examine if my exhaust/intake is choking my engine.
I managed 228RWHP / 290 RWTQ after my rebuild. This is pretty close to the 327 below. I should be closer to 250-260RWHP and 320RWTQ with my engine being a 366 now.
From above:
Notes:
1. + A 1966 L79 (327/350hp) with a fresh stock rebuild run on a chassis dyno, and his best was 238 hp at the rear wheels.
Last edited by stingry; 03-17-2006 at 03:42 PM.
03-19-2006, 08:41 PM
#30
Pro
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Originally Posted by lobo2001
I have the 350/350 11:01 ratio and the solid lifters stock and it is not the LT1. 
Hate to disappoint you, but my '70 L46 definitely has hydraulic lifters, as I've seen them. Also, all of my reference material for my car clearly says they're supposed to be hydraulic. Like the other poster said, only the LT-1 motor had solid lifters.
03-31-2006, 11:06 PM
#31
300 hp stock crappy cam cast intake and 10.5 cr with a q jet 194 valves
350 hp 450/460 lift with 11 to 1 cr same cast intake and q- jet with fuelie heads and 194 valves.
the 202s were on the lt1 a bit later
both hydrailic
amazing the power even the base engine had back then but that is pre emmission and the drop in compression cost 40 hp then the heads even the heads were bounty full
anyone knows you could have just put a cam, intake , holley and headers in and you had 400 horses a little work on the heads and the bigger valves and you were over 450 with stock flat pistons
350 hp 450/460 lift with 11 to 1 cr same cast intake and q- jet with fuelie heads and 194 valves.
the 202s were on the lt1 a bit later
both hydrailic
amazing the power even the base engine had back then but that is pre emmission and the drop in compression cost 40 hp then the heads even the heads were bounty full
anyone knows you could have just put a cam, intake , holley and headers in and you had 400 horses a little work on the heads and the bigger valves and you were over 450 with stock flat pistons
05-09-2006, 10:08 AM
#33
Pro
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Originally Posted by mpett1
That sucks that they never made the 460hp LS6 in the vette.
LS-6s were in Chevelles rated at 450hp & in vettes rated slightly more conservative.
What IS a shame is that they never actually got the LS-7 in a production vehicle, rated at 465hp, real world # indictaed they ran about 550 & more with the simple addition of headers! I know, my bud had a 69 with a installed stock LS-7 with headers
Little hard of drivetrain parts thou!Sorry for the hyjack
05-10-2006, 04:08 PM
#35
Melting Slicks
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6 engines were offered on the 1969.
350/300hp...
L46 - 350/350...
L36 - 427/390.....
L68 - 427/400....
L71/L89 - 427/435...
and........the final motor option.........
L88/ZL1 - 427/560hp.........
ZL1 was an aluminum engine, and only two were sold.
350/300hp...
L46 - 350/350...
L36 - 427/390.....
L68 - 427/400....
L71/L89 - 427/435...
and........the final motor option.........
L88/ZL1 - 427/560hp.........
ZL1 was an aluminum engine, and only two were sold.
09-13-2016, 01:55 PM
#36
Instructor
the NCRS spec book says the 350/300 uses a 6" x 1 1/4" harmonic balancer. cant find that info anywhere else. comes up 8" in every parts book i search. would anyone know the oem number? i have a 69L 12-02-69 build on motor, 3970010 block
Last edited by bucharli; 09-13-2016 at 02:37 PM.
09-13-2016, 04:59 PM
#37
Instructor
and i believe that option cost more then the car did
08-07-2020, 10:34 PM
#38
3rd Gear
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Cylinderheads, cam sh, intake manifold, headers, carburetors, exhaust. Car flies now
08-08-2020, 10:46 AM
#39
Tech Contributor
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This thread is 14 years old. Let it die.
08-08-2020, 02:12 PM
#40
Le Mans Master
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Actually, Lars does have a badge and has a citation book. He just doesn't have a pen right now.