ricwatson

All I pulled the valve covers off to adjust my valves and pulled the casting number off of them. They came back 3973487. I read these were LT1 heads....Any truth to this? That doesnt mean I have an LT1 motor does it? Or is this a typical cast number for a 71?

AF_Vette

Don't know about LT-1s but here ya go

1968-72, 350, 1.94, 1.5
1968-73, 350, 2.02, 1.6

Mike Ward

All '71 SBCs had that casting number as did early '72.

kenpofan

I have a cast # on my 270 hp 350 .
1971..

LT-1 kid

same casting # , the Lt-1s got big valves, screw ins, base got small valves, only dif

David Mc

What LT1 said. With the valve covers off, you should see the screw in studes and guide plates.

You were adjusting the valves because of a mechanical cam? Sounds LT1 - ish to me.