Can't decided on a full LX9 or Top swap

[Dallas3400]

Okay I have a 2005 impala. It has 116,000 miles on it. I've been reading a lot and seems to be the full engine swap can be a pretty big pain. Looks to be the top swap yields just as much of a gain as the full engine swap. Without all the complications.

I'm worried about my aging bottom end. What are my worries with that old of a bottom end?

Now I will be getting a built transmission with 3.29 gears put in before I start anything on the motor.

I just want to know peoples opinion on the top swap vs. Full engine swap.

[pocket-rocket]

I wouldn't worry too much about the bottom end from just a top swap. My 92 has ~145k miles on it IIRC, it's got a few mods (nothing extreme, but did make a decent improvement) and I run it up to 7k regularly on a stock bottom end when I drive it. 116k miles isn't going to do much to weaken the bottom end of your engine.

[Dallas3400]

I'm gonna do the top swap with the 3500 UIM and LIM with the tb adaptor and 65mmtb on the top swap.

My question is, will I still need to modify my fuel rail and coil packs to fit?

[pocket-rocket]

Do you have a 3100 or a 3400, because IIRC if you have a 3100, physically the valves in the 3500 heads are too large to fit in the cylinders of a 3100. Your coil pack should just bolt to the 3500 heads like they do your current engine, and I believe you would reuse your fuel rail since I think the 3500 is a return-less setup.

[Dallas3400]

I have a 05 LA1 3400. so no worries there, and your right about the fuel rail. I will do more research on any modifications I have to do to make it fit with the 3500 UIM

So no adaptors are required to fit the coil packs on the 3500 top end?

[pocket-rocket]

I think the coil packs on the 3500 are different than the 3400, but the spots to mount them should be the same so you would be able to reuse your ICM/coil packs and mount them in their stock location since the 3500 ICM/coil packs mount in the same spot.

[bob442]

if you can have the top end for cheap, when you swap your CR will go down about .5, the only worries you should have about the bottom end is the cam bearings and timing chain. i have the same motor as you, 90,000km, religous synthetic oil changes and my only issues were the timing chain and cam bearings, the bearings had enough wear on them and the chain did have some slight slop, so if your gonna do a cam, its in your favor. if you swap a 3500, you need to adapt a few things, fuel rails, coolant temp sensor, external relucter wheel, coils and TB.
As for the trans i'd get some better clutch packs and maybe some extra steels thrown in to tighten everything up, you can also change your gear ratio with the diff, and swapping to a HD diff is a good idea if you want to drive it hard. i burnt my trans up at 90km too, pretty sure 3rd and 4th clutchs are done!

[Dallas3400]

I have the transmission worked out. Getting a fully built transmission from Milzy Motorsports
HD diff with LSD upgrade 3.29 gears(stock are 2.86)

What stall should i get with the street/strip cam from WOT? or is stock stall fine.

I will also be getting the full competition top swap competition heads, UIM LIM, street/strip cam, 65mm tb, ported exhaust mani, down pipe, gmpp dual exhaust. Tuned PCM for now with raised shift points to compliment the valvetrain.

What would be a ball park estimate of hp and torque numbers with this setup? My goal is to break into the 14s. My car does weigh 3400lbs so it's gonna take a lot

[jmgtp]

I'm gonna do the top swap with the 3500 UIM and LIM with the tb adaptor and 65mmtb on the top swap.

My question is, will I still need to modify my fuel rail and coil packs to fit?

Pocket-rocket is correct - You cannot use the LX9 coils - you would reuse the bracket/ICM/coils from the 3400. The lower bracket bolts will line up however the upper bracket bolts will not line up to the LX9 intake manifold so you will need to get creative there. Not sure if the LX9 relcutor wheel will work with your PCM/ICM. I had to use an external 7x crank trigger but my car is OBD-I. You would also need to use the 3400 rail and injectors.

If you cam the motor you might want to consider a higher stall torque converter, a w-body is a heavy car.

[Dallas3400]

I'm just doing the top swap so the trigger wheel wouldn't be altered

What rpm stall would you suggest with the street strip cam? I'm getting the shift points raised to 7k

[jmgtp]

I couldn't suggest a stall, I've never owned an auto trans - so I can't say I'm even speaking from experience. My thinking is: if you are taking a hit to low end torque (bound to lose some with a larger cam) it'd be detrimental to the cars 'off the line' performance, especially with a car as heavy as a W car. I'd think, performancewise, a higher stall converter would be beneficial and if your building the trans as well this is the time to do it. I guess it comes down to how agressive the street/strip cam is. If you don't take a low end torque loss then it might be ok with stock coverter. I could be way off - somone with auto trans/cam experience needs to chime in.

Can the auto trans take 7k? I think that was the killing factor for auto LQ1 cars.

[pocket-rocket]

Can the auto trans take 7k? I think that was the killing factor for auto LQ1 cars.

Even after raised shift points, the 91 never hit close to 7k with the auto. IIRC it was around 6,500 or so. I don't remember the 4t60e's redline, but it was under what the LQ1 redlined at. No idea about the 4t65e that his Impala might have.

[Dallas3400]

I'm asking my transmission guy, will have a answer for the tread when he tells me


Answer: yeah he says it will easily handle 7k. It's electronically controlled so, some ECM adjustments and we got the recline adjusted, beef up the parts and your good to go