Why is the fuel injected 454 only 310 horse?
10-22-2009, 10:31 PM
#11
Platinum Member
Platinum Member
Join Date: Sep 2006
Location: Colorado / Lake Norman, NC
Posts: 999
Received 0 Likes
on
0 Posts
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.
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.
10-23-2009, 05:48 AM
#12
Registered
Join Date: Sep 2003
Location: Lake Erie, Ohio
Posts: 332
Likes: 0
Received 0 Likes
on
0 Posts
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
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
10-23-2009, 06:31 AM
#13
Registered
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.
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.
10-25-2009, 08:49 AM
#14
Registered
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.
10-25-2009, 06:45 PM
#16
Registered
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.
