2001 VP 5.7 GSI PEFS- new long block options??

[Lubak572]

So I lost my port motor due to water ingestion, and I am looking at replacing with a new long block- might due both motors if I upgrade. I have the the MEFI 3 TBI motors. If possible would like to upgrade performance. These are the some of my options. I will be doing the swap myself. I may even look at getting an L31 HD Vortec Truck motor and marinizing it. Was told at Michigan Motorz the first motor listed is a truck motor that they then change the freeze plugs and oil pan and put their stamp on it-cam is the same. Anyone done this? Was also told there that the TBI motors were more prone to melt a piston vs. the MPI motors. So don't know if I want mess with upgrading as reliability is key. I do have the Rinda software. Anyone know the cam specs of the stock GSI motor and /or the ones listed?

http://www.michiganmotorz.com/350ci-vortec-base-marine-engine-1996-current-replacement-p-109.html

http://www.michiganmotorz.com/350ci-volvo-penta-base-engine-300hp-1999-2015-p-10942.html

http://www.michiganmotorz.com/350ci-volvo-penta-base-engine-320hp-1999-2015-p-10888.html



http://www.michiganmotorz.com/377ci-stroker-base-marine-engine-2000-current-replacement-p-545.html

 

[Scott Danforth]

you can go to your local engine machine shop and build anything you want.

however if you want performance, upgrade from TBI to MPI which would be best to buy a complete motor

yes TBI motors can run lean a bit more if neglected than MPI.

you can get GM crate motors from your local GM dealer as well, then swap the core plugs and head gaskets. however the latest GM crate motors are coming with stainless core plugs and gaskets, so that step is no longer needed.

the best bang for buck performance upgrade will be a 377 or 383 stroker. with the TBI, it will work, however you will need to have the ECM tuned.

if you build a stroker motor, your looking at just under $3k new if you do the assembly yourself. that is a new GM block, new GM vortec heads, new SCAT rotating assembly (cast not forged), and new Comp Cams K-kit. with new exhaust your in it for just about $4k per motor (not including re-tuning your ECM)

stock cam is mild to deal with cheap stock exhaust. you can go up to 270 degrees of duration with a wet exhaust.

 

[Lubak572]

I want to keep the TBI and not sure I want to mess with the ECM. I want to keep reliabilty would rather but a new long block and new exhaust and go. Would any bolt-ons benefit from the stock tune? Like the 377 long block or the VP 300 or 320 (hotter cam) ones linked? I would like to ditch the stock VP exhaust and switch to a hi-tek or Merc dry joint one. Just exploring options. This is on a cabin cruiser with a tight engine bay/hatches, so once it is in I want it to run instead of wrench on it. I am pulling the motor(s) for a winter project.

 

[alldodge]

Exhaust is plug and play for the most part, only issue which may be of thought is connection to Y pipe. Cast to headers will have little effect

Changing a cam will need a retune

 

[Scott Danforth]

the 377 will require a bit more fueling than stock tune - in other words you will need to re-tune- ie, mess with the ECM

a different cam will require more fueling than stock tune - in other words you will need to re-tune - ie, mess with the ECM

if you dont want to change the ECM tune, then stick with 350 cubes and stock cam. you cant have both

the volvo exhaust flows slightly more than the mercury. there was a comparison that Don S posted about 10 years ago or so on that.

Hitek is pricey for what you get. had lots of correspondence back and forth with them about 10-12 years ago. for my needs, I went with CMI because they were local to me at the time.

you may look into EMI or Stainless Marine. your riser height will be determined by your manifold to SWL height