Been referencing this thread since ordering up a set of used heads:
http://www.bonnevilleclub.com/forum/...t=head+casting

They come in, and lo and behold they are neither 2261 nor 4781, but are casting # 8134

Anyone know anything about that casting number?

EDIT: I can say that they DO have the injector bosses in the tops like the 4781 heads, but probiing inside the intake port, I find they do NOT have the injector "pocket" of the 4781 heads.

Here'* pics of the 8134 heads:

are these for porting and to match youre LIM

How sure are you thats a 34 at the end and not an 84?
It sure looks like an 84 on my screen.

I am 99% certain it says 8134. That is backed up by looking at the online product catalog at Rock Auto, which says their OEM replacement head for a 1998 Buick LeSabre Limited is a replacement for casting numbers 2261, 4781, or 8134.

I guess I'm mostly just wondering whether these castings are newer, older, have any known issues, whatever...anyway, they are supposed to be off a 2000 Grand Prix.

Yes. My head/valvetrain plan:

-Use these heads as a guide to port another LIM more perfectly
-Polish all the runners inside the heads
-Smooth and blend the bowls
-Smooth the chambers (using some spare valves to shield valve seats)
-EVER SO SLIGHTLY port the exhaust ports (but NOT the intake ports)
-Three angle valve job (at a shop)
-Undercut valves 25 degrees (at a shop; if machinist says it'* OK)
-Mill 0.020 inches off deck (at a shop; if funds allow)
-Put on LS6 (or CompCams 105#, if funds allow) springs and CompCams retainers
-Put on 1.85 intake / 1.80 (or 1.60, depending on test results) exhaust modded stock rockers

I've removed the valves and inspected these heads for: warpage in the mating surfaces, play in the valveguides, scoring on the valvestems and inside the guides, condition and runout in valve seats, and for cracking between valves, and they've both passed all the tests. Time to buy some more stuff

Anyone?

Perhaps I've made an L36 discovery here, if the 8134 casting number--like the earlier style 2261 head but unlike the '98-'99 4781 casting--does not have the injector hole "pocket" in the intake.

Thats pretty neat. So now there are two good casting numbers to start with.

Here are the same heads, cleaned and purtied up:






I'm still curious though; does anyone know whether this 8134 casting number corresponds with a certain year range?

Here'* some shots of those 8134 L36 heads, with the intake and exhaust runners and bowls polished up a bit (though not ported):