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1993 3.4L iron head to aluminum head questions

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  • 1993 3.4L iron head to aluminum head questions

    Three years ago I posted something about swapping these heads, but I never got around to it. Now the motor is making a BAD sound and I may need to redo the bottom end so I'm thinking now may be the time to tackle this. BTW, the compression is still great.
    I rebuilt a 1993 Camaro 3.4l several years ago and it had been working great until recently. It developed a knock which seems to be a rod bearing or maybe a main. I need to take it out to see. When I rebuilt the motor it was bored out 0.020 on the rod and main bearings and the cylinders were bored to 0.010. I replaced the cam with a 252h from Com Cam for better torque, but I was never really happy with the performance.
    So, now I have a few directions I can go assuming it is a rod bearing that's is causing the knock: 1. I could just ash-can the motor. 2. Rebuild just the lower end and put it back together. If the crank has to be machined then so be it. 3. Rebuild the lower end and upgrade the heads to 3400 aluminum heads.
    If I upgrade, I will have to replace the pistons with the dished ones or the CR will be too high for daily driving. Fortunately, I have access to a Pontiac with the 3400 motor (I forget the year but it's about 1999) so I can use those heads, intake and probably the pistons but I will need headers and probably some other parts. I am hoping that I will only have to hone out the cylinders. This will mean going from throttle body injection and distributor to multiport injection and fully electronic ignition. I'm not sure but I think I can use the Pontiac ecm. I also don't know if I can use the 3.4L connecting rods with the 3400 pistons or if I have to use the 3400 connecting rods.
    Has anyone here done a 3.4L iron head swap to 3400 aluminum heads before? Could you walk me through the process so I have a better idea what I might be facing or point me to a comprehensive post covering the swap? I'm particularly interested in any tricks or mods that would make this swap better or go more smoothly.
    Thanks for any help you can give. Jim
    Last edited by jimjimmyjimjim; 12-23-2018, 05:33 PM.
    1990 Trooper, 3.4L TBI, Comp Cam 252H, Rodeo clutch and front brakes, Superwinch, and funky luggage carrier.