Luther99

Morning all , just picked up a spare 394 engine that was part of the deal with my 59 98 project . Just wandering if any body can tell me if I have the high compression motor , numbers are: block 577476 4 1/8
intake 580677 , 23 drivers side rear of head, head # N209718 , small traces of red paint on generator bracket and oil breather fill , thanks any info is appreciated .

Kahuna

Chances are you do have a high compression motor. One way to be sure is to use a borescope and take a peek through one of the spark plug holes. If the piston head (combustion surface) is virtually flat it's an ultra-high compression engine. If it has a small 'quarter-sized' indent in the centre it's a high compression engine. If it has a larger indent (greater than the rest of the surface area) it's a low-compression engine.

Keep in mind that the engine block, intake and heads would be common on all three of these compression configurations. Therefore, the numbers you provided may not tell you the whole story.

Luther99

Thanks for the reply Paulie , I'm pretty sure I have one of the high compression engines and I will have a look this weekend with a borescope , I'm trying to determine if I have the Sky Rocket version or the higher horse Starfire version. I see some red paint on the engine and it has chrome factory valve covers , the air cleaner decals shows the ultra high compression decal , but only the s is there from either starfire or skyrocket and the lid is NOT chrome like the valve covers , this engine has never been taken apart , came with everything intact including trans .

Kahuna

Yes, both had the factory chrome covers and the air cleaner lid may or may not be the original. In addition to the cylinder head differences, the Starfire engine has a higher performance cam resulting in the slightly higher compression ratio over the SkyRocket. Your best bet is the borescope.

Here is some data on the 394 that you may find helpful:

Charlie Jones

The block number indicates a 61 or 62 engine . Does it have a cast iron timing cover and water pump ?
#23 heads were used on 61 Starfires and all 62 thru 64 394 engines .
There should be an engine unit number stamped on the driver's side head above the center exhaust port , please post that ;

Charlie Jones

The head number N209718 ? Are you sure it wasn't H209718 ?
If so , the heads are 1963 two barrel , high compression .
So much for the claim that it's never been taken apart .
The intake looks to be a 63 or 64 4 barrel .
This pic is from the '63 manual . It shows the difference in the pistons ;

Luther99

Hey Charlie , thanks for the response but now you got me all messed up , dont know what l have , letter N is very clear before the number on the passenger side head , no numbers at all on the drivers side centre pad , just the 23 at the end , raised casting , water pump and timing cover are cast iron , sounds like l have a junk yard dog ?? l am certain the engine came out of a 61 0lds 4dr 88

Oldskeeper

The heads on these engines fit either side and back in the day the heads were swapped out for rebuilt ones.
I would check the piston top markings for correct compression ratio.
The timing chain/ water pump housing on the front is either cast iron (61 and 62) or aluminium (63 and 64), to my knowledge
they do not interchange between the two types.
Post a picture of the front of the engine.
Steve

Kahuna

^^^That is correct, Steve. The water pump is a completely different design.
Also, the piston top designs were different as well. Earlier engines did not have the indents for the valves. Not sure of the years though.

Luther99

Afternoon all , borescoped the engine today , flat top pistons , no indents for valves , found bottom pullely balancer in a bunch of boxes , red paint on that also confused about the heads being 2bbl high compression , cast iron water pump and timing cover ,

Oldskeeper

There were 2 engines with a 2 bbl carb, low was painted a greenish colour and the higher compression was red. With 23 heads I would think the engine is out of a super 88 from 1962. How many grooves in the harmonic balancer pulley will determine weather it had power steering and A/C. One groove would mean just a generator, two for power steering and three for A/C. All 62 394 engines without A/C have a generator and some A/C engines do as well. This was a change over year to alternators and depending on production build date and options you either got a gen or an alt.

Charlie Jones

I made that statement based on the assumption that that Nxxxxxx nmber was actually an Hxxxxxx ,
Since it was not , I will retract that statement . There should be a number stamped on one of the heads . On the pad above the center exhaust port .
If you have no number on either head , then you have two right side heads . The heads will interchange right to left .
As Oldskeeper suggested , probably a '62 Super 88 or 98 engine . Definitely high compression . I would certainly recommend 91 octane or better premium gas .

Kahuna

I concur. '62 Super 88 is my vote. The 4-bbl carb and dual exhaust were available as options on that car.

These engines are quite versatile. I actually have the low-compression 260 hp, 394 with a 2-bbl carb in my car and it's painted a turquoise-green colour. I've already upgraded the exhaust to true dual and next year I will upgrade to a 4-bbl carb with an Offenhauser manifold (if I can find one). When the time comes to rebuild the engine, I'm going to do a full upgrade to Starfire specs - pistons, cam...the works! These rebuild kits are readily available.

Luther99

Morning all , the engine definitely came out of a 61 olds 88 , l seen the car get cut up , the casting no 577476 4 1/8 tells me its a early motor and the flat top pistons with no valve relieve tell me the same , the heads number is confusing , N209718 passenger side centre pad , #23 raised drivers side rear , nothing on centre pad drivers side , were these heads (#23) available in a 2bbl and 4bbl set up ? were the valves different sizes ? There was a thread in 2007 l found on this forum that a gentlemen had the same engine casting # and same 4bbl intake number he pulled out of a old speed boat , I know l have a high compression motor from the red paint l found and flat top pistons . l would just like to know if the heads and intake were changed at one point . l have a cast iron water pump and timing cover , bottom pulley 2 grooves , has a generator , if l was to guess l have a 61 Sky Rocket engine , which would also match the air cleaner decals .

Oldskeeper

The #23 heads were starfire only in 61 and used on all 62 to 64 394's. My guess is that they were swapped out at some point. The heads are to fit on either side so if the number is stamped on the right side and missing on the drivers side they have been replaced.
These heads are one size fits all from 62 to 64 and power is generated by piston design and cam grind, carb size.

These heads were used on all 394's so both 2 and 4 bbl carbs from 62 to 64.

Luther99

Correction everyone , little more scrapin , l found the #23 on the other side head under the generator bracket , both heads are #23 .