i have a low milage (45k) 85' LB9 motor out of a trans am that had front end damage. the owner is selling me the entire car for $500. since my original 84' LG4 motor was equipped with sad compression and a weak cam, i decided it would be benificial to swap in the long block from the T/A but retain my carb setup to have more top end than the LTR setup would produce

however, im not sure of a few things...

1) would my LG4 ECM, PROM, and wiring harness work with this setup, or would i have to swap over to the L69 version for any reason (the electric fans come to mind), or would it be easier to just replace the distributor and carb with non-CC units?

2) would i need to change anything else to make this setup work

i will be picking up the car later this week and will begin the swap right away. any help will be greatly appreciated

 

The LB9 longblock will swap in just fine. It's actually a good move. No wiring changes required.

The L69 and later higher-compression LG4's had a knock sensor, but the L69 at least also had a little more aggressive timing curve. So, in the aggregate, it should be fine. If you get pinging, back the base timing off a little. For sure you shouldn't have any problems with zero degrees base, but should be able to get by with more, like 4 to 6 degrees.

The LB9 exhaust is highly superior to the LG4. If you can get that while you're at it, all the better. Of course, headers and aftermarket back would be even better, but the LB9 won't cost you anything.

That single snorkel air cleaner is about the only thing left holding you back. That, and the carb AV tab, if yours doesn't already open up all the way.