Cobbled Car

Well I'm back for more info / guidance. I am now sure my project car is a 1971 Impala Custom, supposedly a 400 small block.

The reason I say supposedly is that I was told I might want to check the motor mounts and in doing so noticed that the lower front Tab or bolt hole on either side of the cross member actually has no bolt and hangs out past the cross member, essentially holding the motor in place with 3 bolts on either side.

The Motor does not raise or lift up when the throttle is applied but this also raises a question in my mind if this is indeed a 400 small block? I was told the motor was replaced at 20,000 miles by the Dealership under warranty but I suspect they may have put in something other than what the car originally came with otherwise everything would line up as it did from the factory.
I can't think of any other reason for the motor to be to far forward so that the motor mounts would not line up?

I have not yet located any numbers on the block as I need to degrease the engine from an oil leak and 30 plus years of road grim and lack of engine compartment cleaning.

Other things I have noticed is the Heater and Air Conditioning does not work and no air blows threw the vents? I probably will check fusses first but I also noticed the Air Conditioning belt to the compressor is missing. I don't think this would have anything to do with air not blowing inside the car?

I wanted to put a chrome dress up kit on the air filter and valve covers but there are a lot of vacuum hoses and also a pipe running from the header to the air intake? The air intake reads something about turbo 400 something or other and I suspect this is what they are referring to?

Ideas, info or suggestions welcome please.

There's no reason to change the mounts when replacing the 400 even if they used a different engine. All the small block Chevy engines use the same mounts except 55 to 57 that mount on the front.
Maybe you should check the engine numbers to see what you have. You can check them at mortec.com or maybe if you post the numbers someone here would know what it is.

Check the harmonic balancer. The balancer on a 350 is smooth all the way around, while on a 400 it is machined part of the way around. 400sbc's and 454bbc's are externally balanced and to my knowledge all other chevy engines are internally balanced, hence the difference in the balancers. From what I've been told all 400 sbc's came with automatic trans. In order to run a 4 or 5 speed you will need a flywheel from a 454. I ran a 400 sb in a 62 pickup with a 4 speed and that's what I ended up having to do.

Thanks guys, I was looking at it a little closer last night and the motor mounts are welded in place. I don't think the motor is going anywhere but I would like to know what they did. Are the numbers located on the back of the block? I could not see any numbers but again the motor is really grimmy. It appears the oil may be leaking from the valve covers?

The numbers that you need to check are on the flat spot on the block, right below the head, behind the alternator.

JCT440SB,

There is a distonction between frame mounts (which would likely be welded or riveted) and motor mounts. The motor mounts would have 3 bolts holding them to the actual engine block, then there would be a hard ruber insulator with a U shaped pience of metal that would fit over the frame mount. There would be a long bolt going through the tabs of the "U" and the frame mount. Because of mass assembly line production some parts don't use all the holes drilled in them for every application. I suspect the holes you see in your frame mount are just such a case. "the lower front Tab or bolt hole on either side of the cross member actually has no bolt and hangs out past the cross member, essentially holding the motor in place with 3 bolts on either side." I would not worry about how the motor is mounted.

The motor number should be right in front of the passenger side head, stamped into the block. It is not unusual for valve cover gaskets to leak. It is a good idea to de-gunk your motor before you start serious work on it. It will make things much more pleasant and you will be able to see things better. You can visit a detail shop or car wash to do this, or you can purchase a can of engine degreaser and go to the coin car wash and do it yourself. Bring some thing to cover the carburator and avoid directing water around the distrubutor.

Good luck with it

Pat