Sourcing iron head 3.4 parts

[geoffinbc]

Not really anymore. Like everywhere you just need to know where to shop. Some places sell parts and think they are selling gold. But others know the market well and price very competitively.

[nfswift]

Well now I need to form a list of exactly what valvetrain parts I'm gonna need if I go with 3400/3500 heads.

I'll need to go to a 3.4 style cam, IE the Crane 272, because I can't use a roller, but what about the rest of the heads. Do I need to worry about my valve train geometry at all? PR length? Max lift, rocker ratio, lifter style etc? Will I need to custom mount PR guides or the like?

[ForcedFirebird]

No, you can use all the parts associated with the 3500, and all of it's upgrades (from the deck-up). I'm using LS6 springs, 3x00 pushrods (now two 3.4's running around with them, no problems), rockers from the 3500 are a 1.6 ratio and don't require guides, use stock 3.4 lifters.

Basically you keep the 3.4 shortblock and strap everything from the top of the 3500 - with the exception of fuel rail (returnless on 3500) and the TB (drive-by-wire on 3500), both of which can come from a 3400.

[nfswift]

K so I'll be buying a 272, 3.4 style lifters, loaded 3x00 heads, using 3x00 PRs, any length will fit? Topped off with whichever 3x00 intake it takes.

Now for the tricky part, what ECM and harness changes/purchases will I be lookin at? I highly doubt my 86 ECM will play nice with a 3x00 so what is the ideal ECM for the swap/tuning? Is there a harness that is gonna make my life a lot easier too or should I just keep the Fiero one and chop and splice that to pieces?

I guess I gotta dive into this and learn as I go. However, I can't be misplacing my money on expensive door-stops, so I really need a specific list of what I need to pull or purchase.

Edit:
I'm also curious as to what kind of EFI/ignition I'll have to be looking for and adapting to this build. I guess I have a crank trigger (it IS a 95 block), so I may have dodged one bullet? Simply use the stock 3x00 DIS/SFI?