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Welcome to the forum. We need more information to help you with the value of your engine. The 5a heads were used in 1969 on the 350 and also in 1980 on the 307. Are you sure it is a 350? Look for the block casting number to the right of the oil fill tube if you are standing in front of the engine. Also look at the head casting numbers above the center two exhaust ports. Does it have a four barrel intake, headers, uprades or history of maintenance/ rebuild? Does it tick, knock, leak or overheat? If it is a solid main web 350 from 1969 that will be more desirable than any 307, even as a good rebuildable core. After you report back here with this information we can help you better.
If the engine is gold, you may have struck it rich, Dave - The Freak
from what the motor is very dirty. but the heads to have a 5a its a 83 buick
Originally Posted by 67 Cutlass Freak
Welcome to the forum. We need more information to help you with the value of your engine. The 5a heads were used in 1969 on the 350 and also in 1980 on the 307. Are you sure it is a 350? Look for the block casting number to the right of the oil fill tube if you are standing in front of the engine. Also look at the head casting numbers above the center two exhaust ports. Does it have a four barrel intake, headers, uprades or history of maintenance/ rebuild? Does it tick, knock, leak or overheat? If it is a solid main web 350 from 1969 that will be more desirable than any 307, even as a good rebuildable core. After you report back here with this information we can help you better.
If the engine is gold, you may have struck it rich, Dave - The Freak
That number does not come up on my chart. Most block casting numbers are 6 digits. From 1980 - 84 they were 4 digits on the 307's. What was the head casting number?
Look around here for engine ID threads with photos
you cited an intake manifold #
22503087
"MANIFOLD, Intake Manifold, 4-bbl, Iron, Casting ID = #17
Late smog era SB's, most common 403 unit
Lacks 2 mtg holes for Throttle Return Dashpot?
Near Frt LH corner of carb vs. #16
""OLDSMOBILE"" text absent. One boss aft/carb untapped, LH side, on runner to #7. Coolant temp boss LR corner, @ #7 cyl.
Heater Fitting Threads LARGE [3/4""]"
Sounds like an 80's era motor.
"5" [no "A"] heads were 68-9 issue, block ID 395558 - 2 [large "2"]
"5A" heads were used on the later 1977+ engines such as the pre-roller cam 307's
[cannot find block ID for the 307 at this time]
"557752 - 3B" was the block casting ID for the 1977+ 350, which I believe had 3A heads.
Look for this block casting number
aft of water pump/ timing cover, fwd of intake,
under the thermostat bypass hose,
between the oil fill tube on the engine's RH side and the oil pressure sender on the LH side.
Last edited by Octania; January 28th, 2016 at 07:44 PM.
The 69 has a goofy one year balancer if i remembere right but will look more bulkier like the one in this pic. This is a 72 350.
This pic is another one of the 307. I think they all had the air injection set up in the cylinder heads. its hard to make out in this pic but the are all blocked off. This one had 5A heads and the aluminum intake that went with it.
Last edited by coppercutlass; January 28th, 2016 at 06:40 PM.
If you look in the "Home Porting Techniques" thead on page 11 about 3/4 way down, I posted a SB cylinder head chart that was coppied from Joe Mondello's Technical Reference manual - https://classicoldsmobile.com/forums...echniques.html
It shows 5A heads were available in 1969/ 1980. I have never seen an early 5A head.
on this link it mentions there is evidence but does not list it. I thought maybe a replacement head but on the link to the other years it has the KA heads as replacements. Just wondering if there was possibly an optional head or something low production number.
Last edited by coppercutlass; January 28th, 2016 at 07:20 PM.
Chock full of errors too...
example:
#5 heads listed as correct for 1968 "ex. OAI"
but then no other item listed as "with OAI"
yet, 1968 350 with OAI was offered, so what did it use?
Well, it used the same #5 casting I am sure.
With larger valves no doubt, but the same casting.
on this link it mentions there is evidence but does not list it. I thought maybe a replacement head but on the link to the other years it has the KA heads as replacements. Just wondering if there was possibly an optional head or something low production number.
===================
Ka's are BB W30 replacement / marine / industrial uses.
Please note there is perhaps no such thing as a "5a" casting
In the olden days we did not have big n little fonts so a lower case "a" was used to denote a tiny subscript but upper case "A" actually seen on the casting.
Best example
1972 350 heads have a 7a casting 7A
Smog era 307 puny port heads use same size "7" & "A"
7A
In both cases, in real life, the "A" is upper case.
In ASCII text view, the only way to tell one from the other was to use a lower case "a" to -represent- the tiny "A" seen on the earlier head.
Anyhow, get your BLOCK CASTING ID as set forth above and we'll see if it's a 307 or what. I vaguely recall the 307's having a casting ID incorporating "5.0L" in the characters. I would go look at my '85 442, but it has the SMW 403 in it now.
Last edited by Octania; January 28th, 2016 at 08:01 PM.
5A heads were used on the 1981-85 non-roller 307 motors. They at least have "normal-sized" SBO ports. #17 intakes were also used on these 307s (the motor in my 84 Custom Cruiser has one). My money is that this "350" is really a 307.
To the OP: What's the block casting number, directly above the water pump, next to the oil fill tube?
I know ka heads where 455 service heads I used them as an example of being posted as service heads. I know the early A Is smaller and offset. The skinny was the 3A Being on 350's and not the 5A
January 28th, 2016, 05:24 PM
