455 in a 78?
 

Is a 455 out of a catalina the same as the 455's in earlier trans am's? Would it drop in a 78 trans am or I'm I going to need to do alot of work to get it in?

it will drop right in.i have a 73 455 in my 77 formula no prob

What kind of horsepower did a 455 out of a 70 or 71 catalina have?

Not much, but more that enough to get a teenager into big trouble.

i believe 290-310hp

Two different gross horsepower ratings were available in 1970 big cars, 360hp and 370hp. In 1971, the horsepower ratings were net and 280 and 350hp were the only ratings available for the big cars.

You will have to get the F-body engine brackets to make it fit, unless your 78 had the Pontiac 350 or 400, which will work properly...

any of the 455's will fit no problem, just need the engine brackets.

I have a 1970 YH 455 in my 79 TA. I believe the motor originally came from a bonneville