Why is the fuel injected 454 only 310 horse?
 

Why is the fuel injected 454 only 310 horse power? When the fuel injected 350 is 300..just wondering?

Basically, it's a very under stressed big block, designed to run.... well.... forever. It's basic function in life is to provide a lot of torque at low revs, and have minimal maintenance. Small ports, small cam, and low compression give the 310 a long life span.


Darrell.

The 310hp version is called the 7.4. It has a lot more torque than the 300hp/350. It is low powered with longevity and low maintenance in mind. Most of the 7.4's have 2 bolt mains and cast internals.

The 454 magnum mpi has 385hp. They have 4 bolt mains and forged internals.

mrfixxall
 

Heads up! :) i just went through a set of gen 6 310 hp for a friend..they were 4 bolt mains..

Thats why I said "most":D

Actually, I think a lot of the Gen VI's are 4 bolt.

mrfixxall
 

I agree:) everyone i have seen have been 4 bolts..the 310 hp version are gen 6 from what i have delt with..:)

so what your sayin is that the 454 carb motor that was in my buddies baja that I think im buyin will run better then the fuel injected 454 that he wants to put in it?

There are several different versions of BBC, with the 454 there have been carb versions anywhere from 330 to 365 HP (mag) at the crank. The fuel injected engines had to versions 310 and 385 HP (mag) at the prop. Or you can build your own and make whatever you want. :)

they made a 320hp 350 for a few years I have them in my boat all forged internals and 4 bolt mains

Fixall, wat did you have to do to your buddies 7.4? Did you leave them stock?

7.4 is simply the liter designation of ANY 454ci engine.
As I understand it, all GenVI 454's are 4 bolt main.
I think the GenVI started in 96.
Not sure about the earlier variations.

I think all the base 454's (330's,300's,310's) starting in the late 80's came with 4 bolt mains. Reason being, I believe GM stopped producing the 2 bolt blocks. As well all the base motors will have cast cranks, cast pistons, 3/8 rod bolts, small oval(peanut port) heads. All Merc magnum motors got the forged guts, 4 bolt blocks, 7/16 rods, & rectangular port heads.

Gen 5 motors started around 1990, and Gen 6 in 1996. Even the base 454's can make decent power, you just have to watch your RPM.

LE

I had a 310 or 300 hp 454 in my boat and it was a gen 6 4bolt main.
It replaced a 300hp 350. Because the extra torque let me run a bigger prop and yet get on plane easier than the small block it picked up 3mph over the same hp small block.

What he said. My original 7.4L's ran at 4600. That was their peak rpm. The 7.4L Merc model group may go down as the most durable marine motor ever built. At 87 octane, you could not hurt these motors. Errrrrrr, well yes provided you don't run them out of water---------like I did.

mrfixxall
 

Made them into 496 ci....

Believe I read that the 4 bolt mains began with the Gen V 7.4. They do have cast internals though...no forged goodies. Lot's of debate in the past about whether it was worth it to hop the motor up at all. I do recall reading an article on one of the other boards that was published several years ago that said with a decent intake, a set of Vortec heads and some cam work, you could safely squeeze over 400hp from the base Gen V motors without messing with the bottom end.