L69 83-86 "HO" FACTORY Intake Manifold
#1
L69 83-86 "HO" FACTORY Intake Manifold
Can anyone tell me ( FOR SURE ) which one of these Intake Manifold styles was FACTORY install on thier all original 83-86 L69 "HO" motor ??
These are all 82-86 Aluminum intakes with the same part number. The intake with raised "ribs' on ports 2-3-5-8 is about 1 pound heavier than the other 2. ( I removed ALL the fittings before wieghig each. ) The second style has a "checkboard" stamped into the front and back and the third design is plain.
Thanx in advance !
These are all 82-86 Aluminum intakes with the same part number. The intake with raised "ribs' on ports 2-3-5-8 is about 1 pound heavier than the other 2. ( I removed ALL the fittings before wieghig each. ) The second style has a "checkboard" stamped into the front and back and the third design is plain.
Thanx in advance !
#2
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Re: L69 83-86 "HO" FACTORY Intake Manifold
Well, from what I'm seeing...all three have the same cast number, so if one is an L69 manifold (which I doubt the intake is different between it and a standard 305) all three are.
Doing some google searches on the casting number, looks like that intake was used on alot of 305 and 350 engines all the way up to '86 so I again doubt they used a different intake. Mostly I believe the L69 had different heads, and cam.
Doing some google searches on the casting number, looks like that intake was used on alot of 305 and 350 engines all the way up to '86 so I again doubt they used a different intake. Mostly I believe the L69 had different heads, and cam.
Last edited by Klortho; 01-14-2009 at 04:55 PM.
#6
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Re: L69 83-86 "HO" FACTORY Intake Manifold
'82-86 LG4, LU5, and L69 all use the same "416" heads. The reason for different compression ratios is that '82-84 LG4s used dished pistons to yield 8.6:1 compression ratio instead of 9.5:1 with the flat tops the LU5, L69, and later LG4s had.
#7
Re: L69 83-86 "HO" FACTORY Intake Manifold
While the heads were (arguably) the same, the HO motor did receive the larger 1.84 / 1.50 valves compared to the LG4's smaller 1.76 / 1.46 valves (this fact is probably what causes people to argue that the heads were 'different'. It is not that the heads were different, it is the valve sizes that were different!).
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#8
Re: L69 83-86 "HO" FACTORY Intake Manifold
The 1984 L69 engines received bigger valves in the common iron heads, the cam from the 1982 Cross Fire 350 Corvette, flat top pistons, larger H.O. exhaust manifold castings, and the larger exhaust system all the way back. That was what accounted for the 30 HP increase over the regular 305.
The intakes on the L69 was just the same as the ones used on ALL 305 engines. I would say that your intakes were cast during different runs or years, which would account for the difference in appearance. As far as performance goes, the Stock aluminum intake on those cars wasn't too bad and it actually flowed as well or better than some of the lower end 'performance' replacement intakes.
My 1984 15th anniversary T/As have the intake that looks like the lower one in the last picture, from what I remember. I know they don't have all those ribs on there. I will have to go see if they have those 'checkerboards' near the rear.
The intakes on the L69 was just the same as the ones used on ALL 305 engines. I would say that your intakes were cast during different runs or years, which would account for the difference in appearance. As far as performance goes, the Stock aluminum intake on those cars wasn't too bad and it actually flowed as well or better than some of the lower end 'performance' replacement intakes.
My 1984 15th anniversary T/As have the intake that looks like the lower one in the last picture, from what I remember. I know they don't have all those ribs on there. I will have to go see if they have those 'checkerboards' near the rear.
#9
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Re: L69 83-86 "HO" FACTORY Intake Manifold
I can pull the intake from my 85' L69 out of storage and get a pic if your still wanting to know
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Re: L69 83-86 "HO" FACTORY Intake Manifold
My car has the second intake manifold (checkerboard pattern). It was built in mid-'84 (July, I think).
#12
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Car: 1985 IROC-Z
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Re: L69 83-86 "HO" FACTORY Intake Manifold
None of the above
This is off my 85' L69 Iroc
This is off my 85' L69 Iroc
Last edited by iroc_zz; 06-19-2009 at 09:07 AM.
#14
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Car: 1985 IROC-Z
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Re: L69 83-86 "HO" FACTORY Intake Manifold
It would be intresting to find out how many other variations their are.
I wonder if the numbers cast below the "GM CFM" (15, 19, 38, and 45) mean anything?
I wonder if the numbers cast below the "GM CFM" (15, 19, 38, and 45) mean anything?
#15
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Re: L69 83-86 "HO" FACTORY Intake Manifold
I've had 2 '84 l69 cars and both had the middle checkerboard style intake. My current '83 LG4 also has that same intake.
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