Ok correct me if I'm wrong but is this right.

2.8L............ 140HP........... 8.5 to 1 compression stock
3.1L.............150HP........... 8.5 to 1 compression stock
3.4...............160HP........... 9.3 to 1 compression stock

2.8L............ bore 3.5"
3.1L............ bore 3.5"
3.4L..............bore 3.675"

3.4 and 3.1 share rods and crank
3.4 has better heads
2.8 and 3.1 share heads and intake

Please feel free to add details.....

 

Ryan,
THE CHEAPEST & MOST SECURE ANSWERS TO YOUR QUESTIONS
reside in the pages of the GM Performance Parts Book for a measly $6. ANY GM dealer.
BUT, I believe you are correct in many statements. Finding a used running low milage 3.4 is the wisest solution, too.
Planning & waiting is the key.
When mine went (I blew the the 2.8) I was under pressure to get it running.
Out in LA we have lots of wrecking yard options. My 3.4 came from out of the LA area (like upper CA state).

 

those numbers seem pretty close. the mpfi (85-89 lb8) and carb (82-84 lc1) 2.8 had diff heads and cam and the cam on the 3.4 (93-95 l36, i think) is more aggressive.

mike (loomdog)

 

I read in 4X4 off road Ford Races a 2.8 @ 275HP in the Soda Series... They used a 2.8 because it can REV.. Ever see a 2.8 with 4.10's.. It like them a lot...

 

some jeep cherokees had the lb8

 

2.8l vin code "S" (85-89 LB8) has compression of 8.9:1. The 82-84 LC1 (carb'd) motors might have 8.5:1 compression.

I think the 2.8's stroke is 3.3 inches... can anyone confirm this?