If so how much more power would that be?

 

NOT MUCH.
You already have the 3.4 heads on your 3.1 now. EXCPET FOR THE FOLLOWING DETAILS.
3.4 have stronger valve springs and different retainers to compliment the valve springs. AND different valve retainer locks, too.
IF ya got them, port & polish them. AND install new valve guides, NOW. Don't mess with the valve seats, they're already in good shape. Unless ya want to put grinding compound on them and re-seat them by hand or drill.
OR LET YOUR MACHINST BE YOUR GUIDE.

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Chat Soon,
KED85
Karl
1985 Firebird 2.8 to 3.4 swap project for Smog Happy LA, CA

 

yes.

 

Thanks KED for clearing it up.

 

Hey Monkie, IF ya get the GM Perf. Parts book, you can check them out in the 60* V-6 section.
They go for about $400-ish each new.
Where ya get the better power is with the bore & stroke & the cam selection of the 3.4.
The 3.4 cam is linear, not flat & peaky like the 2.8/3.1 cam.

I think many will agree that the 2.8/3.1 cam starts power about 3000RPM then picks up.
It was that way with my original 2.8 in the Firebird & the same cam feeling even in my 1985 S-10 Blazer.

------------------
Chat Soon,
KED85
Karl
1985 Firebird 2.8 to 3.4 swap project for Smog Happy LA, CA