5.7 260 to voretch 350 swap help

[bolo78910]

my friend has a 1986 carver montego and is looking a little more horse power boost,

the engine he got in right now is a merc 5.7 260 , alpha one drive the engine is low on compression, and has a deep internal knock.
he wants to perchase a vortech 350 complete reman long block, what changes will he has to do with the new engine, he plan on using the marine edelbrock 1409 for carb with matching intake.

your thought guys.

 

[twostroke87]

Re: 5.7 260 to voretch 350 swap help

Most vortecs don't have pushrod fuel pumps, so you'll need a marine ignition protected fuel pump.

 

[dan t.]

Re: 5.7 260 to voretch 350 swap help

you may require a different flywheel and coupler. if the original motor has a 1 piece rear main seal you are ok. if it has a 2 piece you need to replace them ,as they have a differernt bolt pattern and ballance

 

[TilliamWe]

Re: 5.7 260 to voretch 350 swap help

Needed:

different flywheel and starter
Different engine coupler for the drive (due to the different flywheel)
Different intake manifold (and I am not sure how plentiful 4bbl Vortec intakes are, cause Mercruiser and VP only use a 2bbl carb on their 5.7 Vortecs.)

Others will know if I am missing anything.
Obviously if the exhaust manifolds are several years old, he should replace them too.

 

[bolo78910]

Re: 5.7 260 to voretch 350 swap help

ok thanks guys . so far the only thing he would have to look at is .

flywheel /coupler
fuel pump
and a four barrel intake

so i gess the mounts and the exhaust is the same setup.

ok i will pass it on thanks guys.

 

[TilliamWe]

Re: 5.7 260 to voretch 350 swap help

I "think" there is a slight difference in the height of the exhaust ports on a Vortec, but I think that the older style manifolds will still line right up. It might be something to watch when putting them back on.