VP 5.7gxi-j- rebuild or remanufactured block

[BRICH1260]

Unfortunately due to a series of unseen circumstances, I am in the need of a new engine block. I think my oil pump let go while at cruising speed.

I need the forums advise on which direction to go. Do I have the existing block pulled and rebuilt or go the route of a reman long block swapping over the needed components from the existing engine. The thoughts of upgrading to a 383 stroker are appealing but I`m not sure if I`d be asking for trouble with my ECM after doing or if the HP difference would be worth it. I`m currently at 320 hp. Is there an advantage rebuilding vs remanufacture?

I`m mechanically inclined but have never done anything of this magnitude, it would make a great winter project, but might be over my head. How much of a DIY is this? or should I just have a professional do it?

Also, where is a good source of reman long blocks, been looking at Michigan Motors website, any others I should consider?

 

[alldodge]

383 stroker are appealing but I`m not sure if I`d be asking for trouble with my ECM

You don't want to do a stroker unless your willing to get a new ECM.

Is there an advantage rebuilding vs remanufacture?

They are the same thing, the difference is one is already done and one you have done. You can either have it done by a machine shop, or have part of it done and you do some of it. All depends on how much your willing to do

 

[Scott Danforth]

I would build it myself, however that is me.

regarding the 320hp version, you can have your local machine shop build you a duplicate. all the parts are GM PP parts

as AD pointed out, if you go stroker, you have to re-tune the ECM

in a big boat, strokers are nice, and you will notice the extra torque. helped a bud go from twin 350's to twin 383 strokers and the difference was phenomenal in the power. the motors dyno'd at about 460hp at 5600 RPM

as far as places for long-blocks

your local GM dealer
your local engine builder
summit racing
jegs
michigan motorz

 

[BRICH1260]

Thanks guys, regarding the 383 upgrade and the ECM re-flash to accommodate, will a Rinda scan tool do this, or does it take a different special tool. If so, how complicated is the re-flash process?

 

[alldodge]

will a Rinda scan tool do this, or does it take a different special tool. If so, how complicated is the re-flash process?

No Rinda is just a scanner, and I believe the GXI has a 555 ECM/PCM and they cannot be reflashed. Whipple says they can reflash but I think they are doing something else, but that is a different story for another thread

 

[BRICH1260]

No Rinda is just a scanner, and I believe the GXI has a 555 ECM/PCM and they cannot be reflashed. Whipple says they can reflash but I think they are doing something else, but that is a different story for another thread

Looking like it might be best just to go back with the 5.7, 320hp that was in there.

 

[Lubak572]

Rinda won't do it, if it is a MEFI ECM you need Mefiburn. If yes see:

http://mefiburn.com/mefituning.asp

I am looking into doing the same, but I I have twin 5.7 GSI's MEFI 3 TBI (280 HP)

 

[Lubak572]

as AD pointed out, if you go stroker, you have to re-tune the ECM

in a big boat, strokers are nice, and you will notice the extra torque. helped a bud go from twin 350's to twin 383 strokers and the difference was phenomenal in the power. the motors dyno'd at about 460hp at 5600 RPM

What motors MPI or TBI? Which ECM? Who tuned it? Thinking of this route.

 

[Scott Danforth]

they were carbs. Holley 750 CFM marine carbs sitting on top of a 1" phenolic spacer on top of an weiand air gap intake. the ignition system was a mallory distributor with a shim kit, the exhaust was EMI's Thunder manifolds, the heads were world products. the engine work was done by Scotty and the boys at Manitowoc Motor Machine, the assembly was done by me, the dyno runs were done at MMM using pump gas, the installation was done at work using the overheads.

The boat was a 1988 Wellcraft

 

[BRICH1260]

If I do install a new motor is there any way of resetting the engine hours stored in the ECM to 0? Will the Rinda tool do that

 

[Scott Danforth]

no, you cant reset the hours. does it really matter?

 

[BRICH1260]

no, you cant reset the hours. does it really matter?

Only for the simplicity of keeping up on maintenance and re-sale tool.

 

[Scott Danforth]

you can explain the new motor with old ECM, new motor and new ECM can also be explained. however as a re-sale tool, honesty and documentation mean more than hours on a motor.

 

[BRICH1260]

I went and spoke with an engine rebuild shop yesterday. He says he can do a 383 stroker kit, over boring cylinder walls, new crank, pistons and heads, all but the cam, keep it stock, and with that I would not have to re-do my ECM. He says that it would not have the maximum HP advantage but that I would gain some HP. He says it would cost an additional 1K over the traditional rebuild cost. Anybody ever heard of this?

 

[Scott Danforth]

should be only a few $ more at best as the cost of a complete kit will save you money over re-conditioning your existing rods or crank. complete forged rotating assembly is only $1140 and is pre-balanced and comes with new balancer

https://www.summitracing.com/search...8+4294951379+4294927933+4294880962+4294882360

just re-conditioning the rods and crank is about $500 and the cost of a new set of pistons/rings and bearings is about $550, so after adjusting for the new balancer, the cost delta is about $60 from re-building a 350 or building a 383

you will still need to re-do your ECM as the fuel demand will be different.

 

[alldodge]

He says he can do a 383 stroker kit, over boring cylinder walls, new crank, pistons and heads, all but the cam, keep it stock, and with that I would not have to re-do my ECM.

I wounder what he's been smoking, must be some real good stuf

 

[BRICH1260]

I wounder what he's been smoking, must be some real good stuf

That what I thought, but wanted to throw it out there in case I was wrong.

Looks like I`m going with a new long block from Michigan Motors and make the component swap myself.

 

[Lubak572]

That what I thought, but wanted to throw it out there in case I was wrong.

Looks like I`m going with a new long block from Michigan Motors and make the component swap myself.

Which one are you looking at I am going that way probably also