NeonHomer Posted February 3, 2003 Report Share Posted February 3, 2003 Okay, I just happen to have access to a set of like new 3.1 heads. I was wondering if there is any performance gain to be had by swapping them in place of my 2.8 heads? (i.e. bigger valves, bigger ports, etc etc) Quote Link to comment Share on other sites More sharing options...
Brian P Posted February 3, 2003 Report Share Posted February 3, 2003 As far as I've heard, they should be identical. What year 3.1 are they from? Quote Link to comment Share on other sites More sharing options...
NeonHomer Posted February 3, 2003 Author Report Share Posted February 3, 2003 They are from a Cavilier convertible. I think it is a 92 model. I wanna say it is a z34 or something like that. The guy just had the motor rebuilt here about 6 months ago, but he got rear-ended, and the insurance company totaled the car. So I want to see if it is worth pulling them or not.. Also, what about the throttle body? Is it the same diameter? Quote Link to comment Share on other sites More sharing options...
Robby1870 Posted February 3, 2003 Report Share Posted February 3, 2003 well, the heads and TB are the exact same. The only differenece in the motors is the stroke. The 2.8 was stroked out to make the 3.1L. However, you could take the heads off the cavalier, get them ported and polished then throw them on your 2.8L. That way, you dont have as much down time on your car, and you got a spare set if you need it. Thats what I would do. And you could port and polish the other TB while you were at it. -Robby Quote Link to comment Share on other sites More sharing options...
Guest Anonymous Posted February 3, 2003 Report Share Posted February 3, 2003 Actually the bore and stroke are different. Other than that they are pretty much the same. Quote Link to comment Share on other sites More sharing options...
Robby1870 Posted February 3, 2003 Report Share Posted February 3, 2003 the bore is different?? I didnt know that........I just though they were the same Quote Link to comment Share on other sites More sharing options...
Redfox340 Posted February 3, 2003 Report Share Posted February 3, 2003 Same here... I thought to get from the 2.8L to the 3.1L was only the stroke... so I heard. :? - RedFox340 Quote Link to comment Share on other sites More sharing options...
Robby1870 Posted February 3, 2003 Report Share Posted February 3, 2003 -RedFox340 Nice looking Monte on your Avatar Quote Link to comment Share on other sites More sharing options...
Brian P Posted February 3, 2003 Report Share Posted February 3, 2003 The block of the 2.8/3.1 is the same, no boring of it was done. However the 3.4 is bigger than the 3.1 because of boring only. Quote Link to comment Share on other sites More sharing options...
Robby1870 Posted February 3, 2003 Report Share Posted February 3, 2003 that is what I thought Brian and I just looked on this site and both the 2.8 and 3.1 have 89mm bores the stroke on the 2.8 is 76mm and the stroke on the 3.1L is 84mm, althought Im sure no really cares -Robby Quote Link to comment Share on other sites More sharing options...
Guest Anonymous Posted February 3, 2003 Report Share Posted February 3, 2003 Then WTF am I thinking of? I really need to sleep more or some at all for that matter! Quote Link to comment Share on other sites More sharing options...
ismellrealbad Posted February 3, 2003 Report Share Posted February 3, 2003 displacement and stroke Displacement 2.8L (2800cc, 173ci) Displacement 3.1L (3100cc, 192ci) I have too much time to sleep.....ill trade u Quote Link to comment Share on other sites More sharing options...
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