Vortec heads on '71 400" SBC - any problems?

[PackardV8]

A guy on another forum has an engine swap he's decoding - a '71 400" with '86 Vortec heads. He bought it in the car and it's been running fine for some years now. However, some guys have him worried it's going to explode any minute because "only the 400" heads and gaskets have the steam holes."

I just realized I've never done exactly that OEM combination of parts. Anything he should know?

jack vines

[binderman]

As long as they drilled the steam holes in the heads and used the right head gasket he will be fine.....

[CNC BLOCKS]

I have run that combo with out steam holes and no problems.

[bigjoe1]

I have built hundreds of 400 engines, WITHOUT the steam holes, and never had a problem.. Guys used to send me their heads for me to drilol the holes, becaused I only charged 80 dollars to do the job, but I never did it for my own stuff---


JOE SHERMAN RACING

[ProPower engines]

The steam holes are only required if there is going to be extended idling time according to GMP
And I have done lots of engines and again never drilled steam holes. From memory the SHP 4.125" dart block does not have then either.
Jack
Are you sure they are 86? Typo maybe? They had what guys call a vortec head with center bolt covers that started in 87 but the real vortec heads did not come out till 1996

[PackardV8]

Thanks for all the reassurances. That will let him relax now.

I haven't actually seen the engine. What he probably has are the post-'87 heads, because they are definitely center bolt.

jack vines

[af2]

The real Vortec head is from 1995 to 2000. A lot of people call the 1986 and on Vortec when they are not. The intake bolt pattern will tell you with 4 per side.