3500 swap or top end build on 3400?

[nh02monte]

I have been reading the posts regarding 3500 swaps and cant decide which option results in the best bang for the buck. I have a 2002 Monte Carlo with the 3400. Currently dealing with a head gasket issue at 137000 miles. 0bviously replacing the head gasket just wouldnt make sense without doing some top end work for more power. I have found a used 3500 with 86000 miles for $300 so it would certainly be a great place to start for a budget build. my budget isnt huge and would like to come away with the best power increase I can for $1500 or so. Will i get more power from the 3500 with some top end modifications than doing the 3500 top swap on the 3400? The head work and manifold work being similar and the displacement being so close I am wondering if there is some other reason to opt for the 3500 swap. Any input would be appreciated.

[bszopi]

Welcome to the site! I guess the first question would be what are your abilities? If you can swap engines (have the space, tools, know-how, vehicle down time, etc), then the engine swap would probably be the best bang for the buck. If you are limited, then the top swap will net you a little less power, but at an overall easier job. Starting with a lower mileage engine would be a nice benefit, but without knowing the history, you may be tearing it down to fix something in a few thousand miles, unless you tear it down and replace gaskets prior to swapping it in, but that adds to the cost. Do you have any future plans to increase the performance of the vehicle?

[nh02monte]

Thanks!

I have actually been following 60degreev6 and wot-tech for quite some time with plans of adding more power than bolt ons will allow. As far as experience is concerned I have and dont have substantial experience. Most of my experience has been with muscle cars and pre OBD II performance builds. Basic principal the same but much more clutter to deal with. That being said, the vehicle is currently down due to the head gasket issue. I have been watching the known manifold gasket leaks for about 50,000 miles and planning a manifold swap to eliminate that problem but I recently began experiencing overheating issues (unless the engine is warmed to operating temp and thermostat open before driving) and what I suspected to be valve noise upon harder acceleration. This issue then raised the question of how far do I want to go. I have added bolt on performance to this vehicle over the years because I enjoy spirited driving. Cold air intake, high flow cat, dual flowmasters, Jet computer, etc. and have given consideration to greater power adders all the while. Who knows if I will ever get beyond a swap and get to the turbo or NOS ideas but I dont want to eliminate them with my current decisions. Time and space are of a bit of a concern but I want to be sure I am making the best decision for all concerns. I figure the swap to be my best bang for the buck as well. My greatest concern is the engine mounts. I have read a lot about the mount issues in regards to other vehicle (grand am, etc) but no one has made any swap comments about the monte so I am not sure if I am setting myself up for major fabrication / modification to make it work in the monte or if newer monte mounts are a simple answer to the issue. Any info will be greatly appreciated!

[nh02monte]

Also, Not much info on the LZ4 or LZ9 swap into the 02 monte but they are both in the monte starting in 06. What is involved in that swap? More than a harness and ECU I assume. Thanks!

[SappySE107]

Drive by wire, so a new gas pedal and wiring along with the wiring harness and computer. No sure on engine mount locations.

[nh02monte]

Thanks Ben!

Ben, Thank you for your replies to both the posts here and the inquiry I made on WOT-Tech. The 3500 will likely be my way to go if the mounts arent an issue in the monte. The good news is the used 3500's I have found do allow some room for playing with that engine in my budget!