310 and 330?
#13
Registered
![Default](/forums/images/icons/icon1.gif)
The carb 7.4L is 330 HP at the crank, and 300 at the prop. The injected 7.4L is 340 HP at the crank, and 310 at the prop. In actuality I think they are the same motor, but the injection is worth about 10 HP. Right? How much is the price difference between these motors?
#14
Registered
Thread Starter
Join Date: Aug 2001
Location: sheffield lake ohio
Posts: 168
Likes: 0
Received 0 Likes
on
0 Posts
![Default](/forums/images/icons/icon1.gif)
the heads are differnt on the 7.4 mpi they are the oval but use the vortech tech to burn the fuel better.
Ive heard the intake was bad also, I think there is a shop that ports and mills them
Ive heard the intake was bad also, I think there is a shop that ports and mills them
#17
Registered
Join Date: Feb 2001
Location: Cedar Rapids, IA, US
Posts: 352
Likes: 0
Received 0 Likes
on
0 Posts
![Default](/forums/images/icons/icon1.gif)
Not trying to advertise, but i've got a Mark VI Magnum roller cam that would slip right in with no spring changes or anything. I was always gonna do this to my motor, and never did. It's brand new. You can contact me offline if your interested. On a desktop dyno program, it indicated it would make about 30hp at 4500rpm than the stock mpi cam. The specs for both are:
Stock cam that you have:
.480 lift intake
.483 lift exhaust
206 duration intake
211 duration exhaust
119 centerline
The mercruiser magnum cam specs are:
.483 lift intake
.483 lift exhaust
224 duration intake
224 duration exhaust
115.5 centerline
The springs in the vortec heads are good to .500 lift, and the roller lifters just swap right over to the next cam, so other than tearing your engine apart, it'd be a no-brainer. I'm not sure how the computer would react to the new cam. That's the uncertain part....????
Stock cam that you have:
.480 lift intake
.483 lift exhaust
206 duration intake
211 duration exhaust
119 centerline
The mercruiser magnum cam specs are:
.483 lift intake
.483 lift exhaust
224 duration intake
224 duration exhaust
115.5 centerline
The springs in the vortec heads are good to .500 lift, and the roller lifters just swap right over to the next cam, so other than tearing your engine apart, it'd be a no-brainer. I'm not sure how the computer would react to the new cam. That's the uncertain part....????
![Confused](/forums/images/smilies/confused.gif)
Thread
Thread Starter
Forum
Replies
Last Post
32 thunder
General Boating Discussion
4
07-23-2004 11:13 PM