3500 swap questions

[3400-95-Modified]

As Ben noted your ECM thinks it has 21lb/hr injectors attached to it. The stock flow rate of the motor vs what your running will only prove that you have an injector with enough flow to support the engine in the end, it doesnt mean your tune is anywhere near close.

Ben are those tested flow numbers? Because that would really explain why I've seen some notes of the Trailblazer injectors not flowing at 28lb's unless your at 62-63PSI

[RedBird]

everything from your 3100 is a direct swap over to the 3500, at least the accessories. i find it hard to believe they'd take the water pump off a genIII motor, but even if they do it's only 25 bucks, and, you'd want to get a 3500 style one anyway, same bolt pattern and fit but it's a better design.

anything that came stock with a genIII motor i'd say is totally worth getting a 3500 to swap. it's an amazing gain, especially over a small port 3100, and almost a direct swap. the work required vs trying to get those same power levels from the 3100 makes it totally worthwhile

[Jonpro03]

FWIW, I never changed the waterpump on my 3500. The powersteering pump bolted right up.

[elementdrummer]

There is a TON of information on a bunch of different cars for this swap. Its hard to find the right pages or my 1999 grand am 3400 to 3500 swap i have started.

Basically heres where I stand, hopefully someone will correct me if I am wrong.

Using 3400 plenum with 3400 gaskets will be port and polished for better flow. This will retain the grand am TB which will be upgraded to 62 or 65mm throttle body.

Using 2000+ 22lb injectors as well as 2000+ FPR and my origional 1999 3400 fuel rails along with new plugs and wires for my 3400.

Using all of 3400 accessories including ignition control module and coil packs. No major issues mounting up besides a/c not having 1 bolt hole it seems.

Will be missing 1 bolt for tranny to engine mount unless I customize. i will use 3500 mounts but use the 3400 oil pan to retain my sensor the 3500 lacks.

Get a WOT tech external crank trigger to solve the 24x sensor. Swap over the arched 7x sensor from my 3400.

I believe most of the other sensors will work so i will leave them in he 3500, may have to do some wiring, but its all the same signals.

Since i am a 99 grand am i will swap my cam sensor over to the 3500.

Which is best to use for rebuild 3400 metal gaskets? or factory 3500 gaskets or is there a felpro that will work? I may do a cam and port and polish the heads as well.
Use 3400 exhaust manifold. hopeully try to score some S&S headers but that is unlikely... may just have to use stock thats my only other option it seems.

Will flatbed car to shop to get a custome tune.

Need some expirience to reply back, will be getting new motor this month, I want to be part of this awesome 3500 swap group haha

[bszopi]

i will use 3500 mounts but use the 3400 oil pan to retain my sensor the 3500 lacks.

Get a WOT tech external crank trigger to solve the 24x sensor. Swap over the arched 7x sensor from my 3400.

You can not use a 3400 oil pan on a 3500 for multiple reasons, the main one being that the holes don't match up. The other being that the 3500 oil pan is clearances in several places for the connecting rods.

I think you have the crank sensors mixed up: 7x is the in-block one (which can not be used with the newer 3500 trigger, hence the WOT-Tech external), and the 24x is the one mounted on the timing cover.

Welcome to the site!!

[boomofdoom88]

You can not use a 3400 oil pan on a 3500 for multiple reasons, the main one being that the holes don't match up. The other being that the 3500 oil pan is clearances in several places for the connecting rods.

I think you have the crank sensors mixed up: 7x is the in-block one (which can not be used with the newer 3500 trigger, hence the WOT-Tech external), and the 24x is the one mounted on the timing cover.

Welcome to the site!!

I used a 3400 oil pan on my 3500 block. No issues with clearances at all. Ive turned the crank over by hand before putting it in the car and nothing hits. And yes 1 perimeter bolt hole is missing in the block. It could be tapped however I used the pan with 1 perimetor bolt missing. Probably not the best solutions, but I have no leaks. As for the lower engine to tranny mount. The solution is a mount that was made for the engine. As the G6 came with a 4t45e, the upper block to tranny mount is a perfect fit and the lower one from the 3400 that bolts to the oil pan lines up perfect as well. No Drilling whatsover needed.

[SappySE107]

Interesting. The block is notched and the pan is matched. I am surprised the stock 3500 connecting rods clear without the pan clearance.

[bszopi]

I used a 3400 oil pan on my 3500 block. No issues with clearances at all. Ive turned the crank over by hand before putting it in the car and nothing hits.

Have you started it yet? Once the engine gets going, things are going to start to stretch, and that's where you might run into issues. GM clearanced the block and pan for a reason...

[boomofdoom88]

yeah I've drove it 4 different days and until hot so I could bleed the air out of the coolant system.

[bszopi]

Well, good luck with it! Hopefully it works for a long time without incident!

[onefastV6]

He isn't the first that I have heard, that has used the 3400 pan on the 3500.
Personally, I am sticking with the 3500 pan.

[PCGUY112887]

I used a 3400 oil pan on my 3500 block. No issues with clearances at all. Ive turned the crank over by hand before putting it in the car and nothing hits. And yes 1 perimeter bolt hole is missing in the block. It could be tapped however I used the pan with 1 perimetor bolt missing. Probably not the best solutions, but I have no leaks. As for the lower engine to tranny mount. The solution is a mount that was made for the engine. As the G6 came with a 4t45e, the upper block to tranny mount is a perfect fit and the lower one from the 3400 that bolts to the oil pan lines up perfect as well. No Drilling whatsover needed.

[ATTACH=CONFIG]5181[/ATTACH][ATTACH=CONFIG]5182[/ATTACH]

Wow, it's been a while since i've logged in here and checked on this thread!

I'm glad to see you have a mount that works. That 4t45e mount that bolts to the engine perfectly, anyone know if the other half would bolt to a 4T60E?

[buickboy]

Hey im new 2 this site i probrebly wont be on here alot but here is the deal i might be able to get ahold of a 1998 GP for $400 and its thrashed, but its a four door se green. The engine in it still runs good its the LG8 but it has 220,*** miles on it and Im wondering what it would take 2 swap the 3500 into it i dont want to go with a 3.8l because its normal and im the kind of guy who wants to be different and i like the 60 degree v6 better than the 90 degree design. but anyway what changes to the 3500 will have to be made to make it work? and about how much money would we be talking. i would probrbly be building the car for my GF to drivearound to work and back 2 so reliability is a factor as well.

[pocket-rocket]

Hey im new 2 this site i probrebly wont be on here alot but here is the deal i might be able to get ahold of a 1998 GP for $400 and its thrashed, but its a four door se green. The engine in it still runs good its the LG8 but it has 220,*** miles on it and Im wondering what it would take 2 swap the 3500 into it i dont want to go with a 3.8l because its normal and im the kind of guy who wants to be different and i like the 60 degree v6 better than the 90 degree design. but anyway what changes to the 3500 will have to be made to make it work? and about how much money would we be talking. i would probrbly be building the car for my GF to drivearound to work and back 2 so reliability is a factor as well.

Welcome to the site! You will find tons of information on this board that will help you along your 60 degree experience. I'm not sure what all is needed for a 3500 into a W body, but the information you want is in this thread, that's why it got stickied. Someone should probably go through this thread and corral all the info into 1 post so we could make it an article...

[RedBird]

if you're looking for a reliable daily driver for your lady-friend then you'd be better off maintaining that current 3100 or putting in another one of same. it's not really worth it to put the 3500 in unless you're specifically looking for a performance gain. personally, i'd throw in a set of metal lower intake gaskets and a *GM* timing chain set and call it good, even with 220K+ miles should run for a good while with those things taken care of.