Using a 93 GT as a 5speed swap Donor for my 95Z, and then...

[3X00-Modified]

They are the same ECM physically... The only difference will be if you buy HPTuners or have a DHP unit. If you have a DHP you can get either and then flash whatever file you want to use, Venture or Monte to it. If you get/have HPTuners you NEED to get a ECU from a Monte because they don't support the Venture file and their program does not allow you to take a bin file and do a full flash to change it's application.

[LOLVTEC]

Ok, so I assume your vote would go to going with DHP?

I'm trying to find tech specs on the 3500... I'm guessing that variations in hp and tq are due to the ECM/tuning car to car? I'd also like to know what the max over vote is and if anyone's beefed up the bottom end (rods and pistons, higher compression etc) of one (not that I'm going to mess with that, I'm just curious).

[3X00-Modified]

Rods and pistons would all be custom work, no known options out there yet... the 3400 the narrow journal SBC rods fit and Diamond already has piston specs to make forged components.

Not saying neither can be done on the 3500, but just no one has done it yet so components that work are just unknown or never been made before by an aftermarket company.

If you can get a DHP it's better yes, but I think HPTuners does have a slightly better interface to work with, never mind the fact that they are still in business so you will get program updates and enhancements to scanning programs and such. Having a DHP your somewhat stuck in a rut with what is currently out there since no one is developing any new software to work with the hardware.

[Rettax3]

I'm with you on not wanting to scrap a good Beretta just because it donated a 5-speed to your even better Beretta... Someone out there wants that auto! Personally, I would not suggest shooting for the 3500 at this time, just because of some of the questions you are asking, the fact that the 3500 comes with a fly-by-wire throttle body that then has to be replaced, and doesn't have a 7x ICM ignition trigger -yes I know the parts are out there, but it is extra expense and extra headache, and for what? About 10% more HP, most of which is contributed by the top-end which can be retrofitted later onto the 3400 block if that 10% is ever REALLY needed. Just my opinion on that. On the other hand, if you do go with a 3400, be sure to update the LIMGs with the steel and rubber ones, NOT GM's crappy plastic. Heck, I would take an old 3.1 MPFI engine over the more powerful 3400 if I wasn't allowed to swap that plastic junk out, just for the reliability issue... I've seen way too many stock 3X00s toasted by the LIMG failure... Thanks GM.

From what you just said about getting the tune 'good enough to drive around with', even doing a 5-speed swap from the GT, and a 3400 swap along with it, your car will run okay with the standard tune in your '95 Z -you might have some odd idle at times, maybe an occasional stall if engine-braking for a long time (like coming down an off-ramp), and probably a check-engine light because the PCM can't find the 4T60E it is looking for. It will still run a lot better than a hack-job tune, so unless you can get help from someone like Eric or Jon, or are willing to lay the car up for a while until you can learn on it, tuning may not be the best way to start off on it... Again, just my opinion. I still have to figiure out the DHP to get the tune right on my 3400/3.1 LG5 Turbo hybrid in my '90 'Retta, but the stock Venture tune is running it fine for now (with very, very low boost ).

Overall, the swap is easy, you have Geoff's write-up now, and Jon has more than enough info on doing an OBD2 swap if you want to go that route. If you find your donor(s), then I say you are ready to go, you should be able to get this done with no problem. Have confidence, have fun, get it done! Make that Z what it should have been from the first day...

[heavywoody]

Rods and pistons would all be custom work, no known options out there yet... the 3400 the narrow journal SBC rods fit and Diamond already has piston specs to make forged components.

Not saying neither can be done on the 3500, but just no one has done it yet so components that work are just unknown or never been made before by an aftermarket company.

If you can get a DHP it's better yes, but I think HPTuners does have a slightly better interface to work with, never mind the fact that they are still in business so you will get program updates and enhancements to scanning programs and such. Having a DHP your somewhat stuck in a rut with what is currently out there since no one is developing any new software to work with the hardware.

Almost two years ago; custom forged rods and custom forged pistons.

Not the cheapest option by far...

http://www.v6z24.com/jbodyforum/drag-bu ... rt,75.html

[3X00-Modified]

I honestly wonder how much that all costs... but that's good info to have.

[heavywoody]

I'm afraid to dig in lol... I met up with a couple 60 degree V6 guys this weekend (came down for the race, WOO! - and to pick up parts off the GT). My plan has been to go fully forged on a 3400 block with 3500 heads and possibly intake manifolds - but one of the guys was convinced a 3500 would be a better starting point.

[3X00-Modified]

I only went to a 3500 for the compression jump without having to buy pistons... Otherwise I probably would have stuck with the 3400 bottom end. Not sure what the advantages are otherwise. Maybe the crank but no one has proven one is definitely stronger than the other.

[Rettax3]

Aren't the stock cams a particular weak point in the 3400s? Hollow, I believe. I worry a little about that on mine since the valvetrain has been modified so much -but it is still running the stock springs from the LG5 turbo 3.1, so I don't think it is taking too much extra stress even with the 3400 roller-rockers machined in on the heads and the shorter pushrods...

I would say that one of the other main things on the bottom-end is to get away from the stock solid aluminum bearings -I have seen some failures on them too that probably would have been okay if they had been a tri-metal design bearing instead.

LOLVTEC, since you asked about CR, according to the calculator on 60degreeV6, my LA1/LG5 3.4 litre hybrid is running 9.94:1 ("Ideal" quench, yay!) on a stock 3400 block, pistons, and rods, with Clevite 77 tri-metal bearings and a 3.1 or 3100 crank (same thing as the 3400, I just mention it because my 68k-mile engine's original crank was eaten up by a LIMG failure, which is why I was able to buy the engine for $60). No issues with the engine's bottom-end thusfar. BTW Jon, what CR are you running now?

[3X00-Modified]

10.5:1 with everything I measured. The cam in the 3500 is exactly the same as the 3400 and the bearings are the same for the mains. I've actually had better luck using oem bearings vs the clevite ones, the mains were oem on my 3400 bottom end and the rods were clevite. I swapped the mains back to the originals because the thrust bearing started to flake apart. This new engine is all OEM bearings, mostly because no one sells any good aftermarket names for bearings. .