3100 Head Swap

[jweir22]

Will 2000 3.1 heads bolt on to my 95 3100 engine.Thanks guys.Just want the roller rockers.

[ikessky]

Yes they will. If you're going with the heads anyway, you should just switch over to the new style intakes as well.

[jweir22]

I would like to do the new style intakes but hard to come buy 2000 intakes used?

[bszopi]

You can also use 3400 intakes from the minivans (Venture, Silhouette, etc) starting in 97.

[ikessky]

If you're patient, they pop up on eBay every now and then. Otherwise, make some calls to your local salvage yards. I bet some places would even be willing to ship to you.

[95Achieva]

Do 2000+ 3100 heads flow better than the 99 and below versions? Or is the manifold design alone responsible for the flow differences between the years?


If swapping the 2000 manifold along with the 2000 heads, can the original 95 3100 air intake, TB, fuel rail, injectors, etc be reused? Or are pieces from a 2000+ needed?

[bszopi]

All 3400 heads and 00+ 3100 heads have slightly larger intake valves (1.76" vs 1.72"), so in reality, they will allow more into the combustion chamber. But as far as actually flowing better, no they don't.

As far as using all of your oold pieces, yes you can. Everything will bolt right up, with the exception of the EGR.

[Pinoy]

everything will work except for roller rockers (stamped on the 3100s) currect brad? how bout replacing injectors, would that be a good time to replace them as well? maybe upgrade them to 3400s as well?

[bszopi]

3100s only had stamped rockers for the first 2 years. They began getting roller rockers in 96. As far as injectors, stick with what you have. If you attempt to put in a different set, the PCM won't know and it'll just end up screwing with things. This has been discussed several times... people always seem to have issues when trying to swap in the Multec-IIs.