[mike_1971]

Just purchased a 1971 Chevelle needs lots of work but I think it is amazing. Was checking engine to see if it could be original. It has a engine number of T0909CMJ I looked up CMJ says it could be a 1974 350 police, or a 1980 305 this seems like to very different engines and probably not a matching numbers. Casting number is a 3070010 can anyone help?

 

[bracketchev1221]

Most likely casting number 3970010 which is a common 350 block.

 

[mike_1971]

Adding two pics of engine numbers

 

[mike_1971]

And the casting was done upside down ?

 

[mike_1971]

The Chevelle has been sit up for 22 years I remember it back in high school it was a really nice car, interesting color combo Sandalwood outside and inside.

 

[mike_1971]

It also had a dark brown vinyl top and stripes, it may not be the most popular colors but it really looked good back in the day.

 

[Ericnova72]

The #3970010 block casting is a 4.00" bore block....so it can't be the 1980 305 engine application, since the 305 has a tiny 3.736" bore size.

That's why both casting number and application code are often both need to nail down the identification.....if Chevrolet hadn't reused codes in different years and different applications, then we wouldn't need both sets of numbers to ID a block.

Good news is that it is a 350, probably 4 bolt main but you'll need to pull the pan to know for sure.

Bad news is it isn't original to the car, if that matters to you.

 

[mike_1971]

Great info thanks for the help. Original or not that's fine just glad it is the 350. Its a two barrel carb will work on changing the intake to a four barrel. The engine runs good but it needs everything restored.

 

[DUTCH MAX HEADWORK]

The casting date off of that block will help you pin down the date of that code and block.

 

[mike_1971]

I will look for that next thanks.