71chevy 350 engine

[MickG]

I just purchased a 71 K20 pickup truck and I was told by the previous owner that the engine is a 350 small block that was rebuilt. My factory label on the inside of the glovebox door listed a LS9 350 engine.I picked the numbers off of the block and it is a GM 3970010. When I checked these numbers the first site I found said this matches a 69 Z28 Camaro 302 small block. I also found a site that said GM used this same number to ID their 327 and 350 that same year since the 350 was first introduced in 69. Since my truck was ordered with a 350 engine can it be possible that this is my original block?? Does anyone have any info the 350 small block engine??

[tim71]

My 71 GMC K1500 has the 3970010 block. The number on the pad in front of the passenger side head will give you better info on what the engine originally came in.

[Coley]

As Tim said...the 397 is simply the casting number and was used for a variety of applications including, trucks, cars, vans, etc.
You have to take a long look at the revealed casting area on the front, passenger side of the engine block...just ahead of the head.
There will be a surface there around 3"-4" long and it will have some alpha numerics stamped into it.
This is the information that will determine what your engine came in.

Welcome to the forum!!

Coley