7.4L versus 454 magnum
 

my book for the boat shows these both as options, aren't these both the same displacement?? my boat shows 7.4l on the back of it, but is it a mangum or just a plain 454. the previous owner said it was a 360 hp, but i haven't found anything that would prove that yet.

Re: 7.4L versus 454 magnum
 

what year?most 454 mags are 365 or 385 hp. The reg 454 is 300 or 330hp

Re: 7.4L versus 454 magnum
 

1990 baja 210 ess, how do i tell if it has a mag or just the standard

Re: 7.4L versus 454 magnum
 

Check the block code. Front passenger side. XW=7.4, XA=Mag

Re: 7.4L versus 454 magnum
 

is there more numbers than that, or is that it?? i'm curious what this engine is now, the previous owner told me it was 360 hp, but i think it may be less now, which would bite

Re: 7.4L versus 454 magnum
 

Those are the last 2 letters in the code.

Re: 7.4L versus 454 magnum
 

that's part of the #'s. Mags have rect intake heads,high rise intake,4 bolt mains,bigger rods,forged pistons,and bigger cam.

Re: 7.4L versus 454 magnum
 

Easiest way I know is that a 454Mag will have an aluminum high rise intake, 305HP/7.4 will have a low cast iron intake...
If you have a Mag. in a 21', it must be quite the screamer!

Re: 7.4L versus 454 magnum
 

Quick test for HP intake, if it is magnetic it's the standard 454/310, if it's not then it might be a 454/Mag. However, someone could have put an intake and carb on it aftermarket, but that is unlikely.

Re: 7.4L versus 454 magnum
 

With 360 HP in a 21 footer you should be in the 70's(GPS) for speed.