Offroadunleashed

Here is my tentative plan currently with my knowledge at this time. I would like to have an iron block ls engine swapped in place of my 350 pontiac. End goal is LS T56 combo. I currently am running a TH350 but the problem is the bolt pattern of the trans. I was thinking of when doing the LS swap, I would get a TH350 from a chev and swap it in place because it should have the same outer dimensions, right? That would save me a drive line and cutting the floor for the time being. The whole idea of this swap is budget and power, but more budget. I was thinking an Iron block 5.3 from a truck because if it ***** up I can get it bored out in the future and my supply of running engines would be limited. From what I understand non running condition blocks, Iron is less of a gamble. I also heard that the Iron block is more durable and I would like to run boost in the far far away future. To keep it on a budget I would like to run as much of the truck engine parts as possible. The car has a Ram air hood which has no extra clearance than a stock hood, possibly even less. Cowl hood isn't an option to gain more clearance. From what I've read it would be less work to switch to a ls1 oil pan. I would like to run the stock accessory drive and intake if that is possible but if it isn't I wouldn't mind the looks of it, just would be harder on the budget. Having an early model 2nd gen Firebird I believe I have the clamshell motor mounts, I'm not sure what to use to mount the engine, again on a budget. Wiring harness I don't see as much of an obstacle. I am willing to work with anything. I would have to delete some stuff reguardless and wouldn't mind the challenge of messing with the harness. Oh and the fuel stuff I have no clue about so I would need some education about the return fuel system. My car has a very new looking fuel tank so I would be willing to use it as the donor in the LS Swap because it should not be internally rusty as it is minty underneath. That's all I can think of right now. Some help, advice, estimates, and general knowledge would be appreciated. I have access to some cheap TH350s. 5.3's would be $700-$800. Harness I have no idea along with fuel system cost. I believe depending on what TH350 I got I would need a spacer for it.

USNDV

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USNDV

I'm in the process of installing a 5.3 in my 69 GTO. I am keeping my TKO 500 and modified the drive shaft and floor pan when I installed it prior to the LS swap. I did have to switch from mechanical to hydraulic linkage. The truck intake fit under my hood, but I bought and LS1 intake for looks (might swap for a LS6 later). I did have buy a corvette water pump, spacers and idler pulley to install the car intake. I did buy a new oil pan. The front truck accessories can be ran in the vehicle. I used BRP hotrod motor mounts. (The original builder bought some cheap trans depo stuff that was bent and did not fit). I purchased my wiring harness and fuel system from PSI conversion. I also bought a cam package from Texas speed shop and had them reprogram the computer to match the cam. I was able to use a 92 impala fuel tank for my build. I would also go with the 6.0, my builder talked me into the 5.3 but I would have rather have a 6.0 more options for super chargers heads, and more power.

Offroadunleashed

Did you have a chev engine in before? I a wondering if you had to change the bell housing. Do you think there is the same room in the engine bay gto vs firebird. How come you had to switch linkage? Lastly how did you get the impala tank to work? much modifying? Was the impala previously a v8? or does that matter?

USNDV

I had a Pontiac 461, I had to buy a new bell housing to connect to the LS engine. I don't think it is the same space in the engine bay, but a LS engine should fit. I switched the linkage because I did not want to drill into the LS block to mount the linkage. When I installed the gas tank, I cut an access panel in my trunk so I could get to the in tank fuel pump with out dropping the fuel tank. It also allowed me to mount the fuel tank higher. It fit in between the frame rails so all I had to do was extend the tank straps by about 2 inches. I believe the impalas are V8