2001 GP swap in a 3400

[carsan57]

Is it a direct swap to drop in a 3400 in place of the 3100. I just purchased a motor out of an 2002 GA. I just wanted to make sure, It looks like the wiring harness is a little diffrent but i was just going to use the one of the 3100.

Also would going with a set of forged pistons end the piston slap these suffer from in later miles?

[IsaacHayes]

2001 3100 to 2002 3400 will be a direct swap yes. Only thing you will gain is .3L more displacement in the form of a larger bore other wise the motors are the same for those years top end and bottom end. Just a block that allows for the bigger bore.

Don't worry about the piston slap, not worth 600 bucks for custom pistons. Unless you want to bump up the compression or something. Mine has a little piston slap but runs strong at 200k+ miles on my 94 3100. Once it warms up it's quiet.

Worry more about the intake gaskets (which probably took out your 3100 if that's why you are replacing it). Put on the metal felpro or dorman intake gasekts on the 3400 before you slap it in. Use a torque wrench and torque in the proper order the instructions that come wiht it say. Then you won't have to worry about the motor.

[carsan57]

No I'm just getting a motor ready to put in, I have 226,000 on the gp and it runs fine but i know it wont last forever, since we've already got a replacement vehical, I just wanted to play with this alittle, the 3400 was going to get a diffrent cam and a 3500 upper, I have no plans on turbo or charger so I didn't know if forged would really be needed, but i also dont want the piston slap. Its getting a set of S&S headers, and i need to find someone to tune the computer, the trans has already been rebuilt, I figured that combination would wake it up a little bit and still be very drivable, since im going with the 3500 heads would i be better off a 9:1 piston someone set that those heads with the factory 9.5:1 woul give it 11:1, i just think thats a little much. Whats your opinion on this combo?
thanks
Carl

[SappySE107]

3500 heads on a 3400 is about 9.1:1 compression. Camaro pistons would be around 11:1 compression if you want to go that route.

[carsan57]

That's a relief i was worried about that kind of compression, so would forged pistons be need if its a non turbo or charged, but with other upgrades.

[SappySE107]

If you can tune it properly, then a good hyper eutectic piston will work just fine for a non boosted application.