fast68 Posted September 15, 2003 Report Share Posted September 15, 2003 will this work: pair of early 87-up MPFI aluminum 2.8L cylinder heads(with the common older common flat top style upper plenum) onto a 3.1L with same style flat top upper plenum that also has aluminum heads, 1987-up 2.8L heads casting number 10048651 1992-?? 3.1L heads casting number 10048696 i have not seen anything that looks to be different so far that would prevent using the 2.8L heads on the 3.1L, the 3.1L is a 1992 and the 2.8L appears to be the same year or right next to it, maybe would i need to get head gasket set(topend gasket set) for the 2.8L or the 3.1L for this heads pair swap ? the 3.1L heads have bent over valves due to timing chain breakage. i appreciate anything at all. thanks update: i found out today that the head gaskets are same betweent he engines but the uper plenum intake gaskets differ, i got printout of the gasket sets for both, i have not yet put the plenums upside down and side by side, but the lower intake gaskets show to be same between these two engines so i dont see why i can use the 3.1L lower intake onthe 2.8L heads anyone? thanks! Quote Link to comment Share on other sites More sharing options...
Robby1870 Posted September 15, 2003 Report Share Posted September 15, 2003 So, you want to put 88+ Aluminum heads from a 2.8 on your 92 3.1L? That should be fine, they are the same head. However, if the heads are from an 87, then they are iron on wont line up with your intakes on your 3.1L. And the gasket differences you are talking about, do you mean the plenum gaskets? If so, I can explain why Robby Quote Link to comment Share on other sites More sharing options...
fast68 Posted September 16, 2003 Author Report Share Posted September 16, 2003 So, you want to put 88+ Aluminum heads from a 2.8 on your 92 3.1L? That should be fine, they are the same head. However, if the heads are from an 87, then they are iron on wont line up with your intakes on your 3.1L. And the gasket differences you are talking about, do you mean the plenum gaskets? If so, I can explain why Robby thanks Robby, yeah the 2.8L heads are 89 if the stamping code on the outside corner of them is the date code, ends with a 9 and they are aluminum also, yep i have not found any casting date codes so i assume in a certain year or only on aluminum parts GM never cast the dates for some reason, the code on the outside of one of the 2.8L heads is A079 and other head looks like A078, htese reallylook like GM date codes to me that sound good ? and yeah the upper plenum-to-lower intake gaskets differ from 2.8 to 3.1 for some reason evne thoguh it appears all restof gaskets are identical between the two engines, holes are in different locations especially on one of the two plenum gaskets why is this ? im up for learning tech info, thats what i live for, soo.. thanks! R Quote Link to comment Share on other sites More sharing options...
Robby1870 Posted September 16, 2003 Report Share Posted September 16, 2003 As long as they are aluminum then you are fine. It doesnt matter what head gasket set you get, its the same block and same heads. Only difference in the 2.8/3.1 is the crank and pistons. Robby Quote Link to comment Share on other sites More sharing options...
fast68 Posted September 16, 2003 Author Report Share Posted September 16, 2003 As long as they are aluminum then you are fine. It doesnt matter what head gasket set you get, its the same block and same heads. Only difference in the 2.8/3.1 is the crank and pistons. Robby awesome, i appreciate, yeah i believe 2.8 was just over bored to make the 3.1 and then 3.1 was either bored or stroked or both out to make it the 3.4 something like that thanks! R Quote Link to comment Share on other sites More sharing options...
Robby1870 Posted September 16, 2003 Report Share Posted September 16, 2003 2.8L was stroked 8mm to get 3.1L. 3.1L was bored 3mm to get 3.4L displacement. However, the 3.4 is a completely different motor than the 2.8/3.1 Robby Quote Link to comment Share on other sites More sharing options...
fast68 Posted September 16, 2003 Author Report Share Posted September 16, 2003 oh, hmm,,, interesting. thanks! Quote Link to comment Share on other sites More sharing options...
turbostewhite Posted September 20, 2003 Report Share Posted September 20, 2003 2.8 and 3.1 heads are the same 88 to 93. Quote Link to comment Share on other sites More sharing options...
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