Skatepunk60

Ok i might have a cracked head on my 2.8 MPFI could i swap on some good 3.4 heads w/ no problems ands maybe gain a few more ponies i heard these are good.

Thanks

KED85

Mind if I be honest
USUALLY when a head cracks, gasket blows etc...
Two choices....
How lucky do you feel?
Either you have success (I haven't) or you conceide & swap in the complete 3.4 from where you scored those heads!
The 3.4 heads are better for several reasons
UPFRONT
NO internal passage modification was performed.
The spring pocket area was given extra meat to allow a dual spring to be used and a larger one (than the 2.8/3.1) at that. Just like the old Z-28/LT-1 HiPo head days.
Valve size is identical for ALL RWD MPFI Heads.
Go get the GM Performance parts book for $6 at any GM dealer & check out all the 60* V-6 specs for the 3.4.
Honest, spend more time finding a better engine than patching that one up.
9 times outta 10, when that damage happens to these little engines, say bye....
Spoken from experience at 211,500 miles of 2.8 V-6 life.
See below the Blazer (Firebird 2.8 died at 105K), almost done with the 3.4 installation.
My 3.4 I got reads 150 PSI per cylinder, quite good for a 50K mile engine.
I paid $900 for my used 3.4 for my Blazer.
I spent $800 for the used one (with 175-200 PSI per cylinder) in my Firebird.
I just read of someone spending $3000 rebuilding a 2.8. Someone elase spent $1800 rebuilding their 2.8.
One can buy a BRAND NEW GM warrantied RWD 3.4 crate motor long block (165 HP & 200 Ft Lbs torque!) for $1600 or less CASH.
Some have reported obtaining a complete 3.4 for $210 (correction noted!), average seems to be about $500 (depending upon milage, too!).
Seriously, seek out better solutions.........
ONLY
IF
YOU
SERIOUSLY
LOVE
YOUR
F BODY
Cause this 2.8->3.4 Long Block Swap Boogie is a detailed easy mission.
Beyond ThaT grab those heads now!
Get the complete engine, too!!

Project: 85 2.8 bird

& remember, I started off being told that my car just had a blown head gasket, I look where it lead me

and Karl, it was $210 for the 3.4

Skatepunk60

Yeah the engine still runs but she leaks oil like a **** onto the exhaust manifold and its not like a normal valve cover gasket leak its like the gaskets not there and the valve cover is raised .. so im thinking i might have a crack in the head. I havent found a 3.4 block yet .. i havent even looked yet but my engine has 132,000 miles on it but im gonna sell her in favor of a 84 T/a in a couple of years so do ya think i should go with the 3.4 heads or just get some 3.1/2.8 heads. I doubt the block is damaged but it might be cause i dont run her long enough to really find out.

Project: 85 2.8 bird

2.8/3.1/3.4 heads are the same. diff will be how old/strong the valve springs are.