Ok soon enough i'm gonna get myself an LT1 block for my 86 Trans Am. I need to know if there is a diffference between the long block and short block. If there is will it still fit in the car exactly the same. I need this to be as easy as possible on my part.

Sooner or later i'll convert it to a LT4 giving me a garanteed 450hp.


And another question will it be better for me to keep my current transmission on my 305 ci block, or to get the LT1 engines transmition and use it. I mean i know mine has prolly more wear and tear but its $650 more than without the transmision. Its like $1500, with it and $850 without. Which would be the better choice, the engines both have same mileage about 80k miles, mine has 120k currently.

 

short block = engine with internal components (rotating assembly/camshaft/timing chain) - sometimes have oil pump & pan, sometimes do not

long block = short block + cylinder heads - always come with oil pump & pan

As for the tranny, neither the T5 or T56 are rated for 450 HP, but the T56 is definately stronger.

If I were you, I would keep the T5 until you break it - then upgrade. I currently have a T5 behind a 408 SBC putting out an estimated 420 horsepower.

edit:
Just realized, you didn't specify manual or auto tranny. If you have an auto, I don't know the difference between yours and one that would come on an LT1 equipped car.

 

you would have a lot more room with the short block since it lacks heads, an intake, a cam,an induction system, and probably an oil pan and pump. the long block will take up considerably more room.