my 76 ray

Here is a picture of the engine in my new '74



An Edelbrock Performer 600 CFM carb sits on an Edelbrock Victor Jr manifold



It has 1.5 Crane roller rockers





There is a big aluminum block that sits on top of the rockers. I think its purpose
is to lock the adjustment on the rockers. Does anyone know what it is called?



Now to the confusing parts.
The head casting number is 3927186



When I look up that number it says it is 63cc 2.02/1.94 Intake 1.60/1.50 Exhaust
It says it is from 68-72 302/350. I think the first numbers might all correspond, so

2.02 Intake 1.60 Exhaust for the 302 engine which would probably mean that's what
was on the Z28 Camaros.

1.94 Intake 1.50 Exhaust for the 350 engines.

So now I don't know if someone put a Z28 engine in the Vette or is it a 350 so I
look at the stamp pad and the engine has been decked at some time. So I look at
the casting number on the block and it is 3970010 and when I look that up
it can be:
3970010 350 69 Corvette Late 69, 4 Bolt Main
3970010 302 69 Camaro Z/28, Late 69, 4 Bolt Main
3970010 350 69-79 Truck 2 & 4 Bolt Main
3970010 350 69-79 Pass, Chevelle, Camaro, Nova, Monte Carlo 2 & 4 Bolt Main
3970010 350 70 Corvette 300, 350, 370 HP Bolt Main
3970010 350 71 Corvette 270, 330 HP, 4 Bolt Main
3970010 350 72 Corvette 200, 225 HP, 4 Bolt Main

So I still don't know what it is. I read that all the 397010's are 4.00 bores.
I should be able to get the cubic inches by measuring the connecting rods.
But, is there any way to determine the valve sizes without pulling the head.
I hate to tear apart a good running engine just to find out what valve size
I have.

Tomorrow I'm going to try to set up a dial indicator on top of the push rod
ends of the rockers to see if I can get a close reading on the lift of the cam
by turning the engine over by hand. Do you think that will work?

Thanks for any advice you can give me.

MotorHead

How does it run ?

my 76 ray

Runs great. I would just like to know what's in it, but, not enough to do a tear down that isn't necessary.

SpeedyGjr

There is a big aluminum block that sits on top of the rockers. I think its purpose
is to lock the adjustment on the rockers. Does anyone know what it is called?



Thats a stud girdle. The rocker studs tend to bend/distort at high rpm's causing the rocker itself to move a bit. The stud girdle ties all the studs together,

my 76 ray

Wow! Now I really wonder what the build of the engine is if the person who built it felt it was necessary.

Thanks.