Gannz

I have a 95 305 Merc with a cracked block and I'd like to repower with a 350 Vortec. I've been reading for days and I've been able to search and confirm that I can use an 87-95 350 block with the 96-up Vortec heads as long as it also has the Vortec intake. But, I can't find if I can just drop in a 96-up 350 Vortec long block and still have the bolt on parts from my 95 fit... manifold, distributor, water pump, engine mounts, etc.

If the Vortec heads/intake fit the older block it makes sense that the 95-96 block is the same and all the other parts will fit. I'd like to get a 96-up marine Vortec long block and reuse all the other parts from my 95 305 but the 2BB carb and manual fuel pump that I'll switch to a 4BB with electric fuel pump. Can anyone confirm that this will work?

befu

iTrader: (2)

Pretty much any 350 will take the vortecs, the 87 and up will mean the block will have a one piece rear main seal and early 90's and later the block should be machined for roller lifters.

The only thing is you will need a harmonic balance and flywheel for the one piece rear main seal. Everything else should transfer over. Exhaust, distributor, water pump, motor mounts, bell housing will all bolt up. But the Vortec heads need a Vortec intake manifold.

befu

iTrader: (2)

Might be better to look for a take out that is still in good shape. Carb, intake manifold, flywheel and balancer will add up. Carb needs an electric choke as the Vortec heads do not have the cross over to warm the choke spring.

Sorry, I do not sound clear, too many allergy meds.....

Brian

Gannz

Thanks for the reply. My engine has a one piece rear seal...

14093627...305...87-94...2...Roller or flat tappet cam, one-piece rear seal

My harmonic balancer and flywheel won't work on a 96-up vortec 350?

airjunky

iTrader: (2)

Vortec block with the plastic cover I believe will use different harmonic balancer due to different nose depth .vortec block pistons and rods are different , lighter .get the whole shin dig swap out with ht383 cam and some roller lifters that haven't seen water in oil damn sure make sure what ever heads you use has good valves in it (not reman cheapies)and be one with the 35% power increase !.your money is gonna go to the intake cam maybe lifters .and a new prop .

Gannz

Which vortec heads have the 35% power increase?

airjunky

iTrader: (2)

The ones with the 8 bolt holes that hold the intake down , heart shaped chambers ,usually run plastic valve covers ,and come on 5.7 mercs and Volvo penta and 96-00 gm light trucks

bkaltec

Your pulleys may be the only questionable items. And yes you'll need a carbed vortec intake manifold. Everything else will bolt up.

You can use a truck long block, the main differences being the freeze plugs, if you are in salt water you definitely want to change to brass and the cam. The cam will have lots of low end torque which will get you out of the hole faster, but not much duration for running top end. If you change cams, be cautious of lift, vortec heads can only handle less than .450". Between 0.450 and 0.500 you chance crushing the valve seals. Greater than 0.500 you will crush the seals and possibly damage the valve train.

airjunky

iTrader: (2)

Yep .even if it has titanium coated Kevlar freeze plugs , pull em , clean that block out good .ht383. Crate motor cam is the cam from gm that merc used on roller 305's up to the scorpion with the ram jet intake .much more than that your into reversion mods and head mods .the 250 horse truck motor is the 300 horse boat motor in non emissions form ,gm sells a bunch of em to the street car crowd

Jonesyfxr

iTrader: (1)

I think you could find a complete engine on CL and get exactly what you're looking for.