is it me or does it seem the 855 Vortec heads OUTFLOW the other castings of the Vortec head?

My real question is....are the 062, etc etc etc 855 all the same (L-31) 64 cc head??? I always see a little more flow on the 855's on someones website or something like that. Maybee its coincidence.

 

I don't know but I would like to. If you find out, let me know. PLEASE.

 

I have never actually seen a Vortec with a "855" casting number.
Just 062 an 906. I have never ran across any one who has ever seen them either.
Do they really exist? I have seen different, conflicting flow numbers for "stock" vortec heads too.

All I really know is what mine flowed when tested and
what we've accomplished with other sets.

They do work good though.

 

I've *heard* that some of the Vortec heads have actual exhaust seats, others have castings that are just hardened in the seat area, INSTEAD of actual pressed in valve seats.

I have no idea if this is true in reality, if it is, I can't find anything online (easily) that proves or disproves this. Not sure how long they used these heads (if still) but I did see an article on 2001 GM trucks that mentioned better exhaust seats, but of course no specifics.

 

Yes some of the heads had pressed in ex seats.

Some heavy duty trucks, propane and industrial/ marine applications.

No big deal though. They work all the same.

 

So is there any rhyme, reason, or casting number that did or did not get pressed in seats that you know of? Started using pressed in (hardened) seats in the early 70's, (I know, no lead, and there still isn't any) removing them can't help longevity IMO.

Not that I'm going to be really hard on it for 50,000 miles straight, but valve recession shouldn't be an issue on heads this new, and I don't want them to be scrap or have to have pockets cut and seats installed in 100,000 miles, when an older head would just need a valve job.

They work the same, obviously, but GM wouldn't have spent the money if they didn't think or know it would be a problem in some cases. How do *I* know my application isn't one of the problems? Obviously thats exagerrated a bit, but if anything fails on my vehicles, valve seats shouldn't be even in the top 100 list.

 

The ones without pressed in ex seats have flame hardened
exhaust seats from the factory. If you get a chance to see
a brand new bare casting, the exhaust seat looks scorched. cause it is. (flame hardening)

They are used in trucks and marine motors
they will last.

 

I'm gonna take your word for it!