Putting 98 Vortec 350 into 85 305 hole - what do I need to know?

[9511234]

Here's what I've got.

My friend had a problem with a distributor shredding out on a cam - it happened when a mechanic put his distributor on from replacing the intake gasket.  We pulled the cam and it has some scratches - but overall it is in good shape.  We pulled the valve covers and don't see anything crazy up there.  We pulled the oil pan and checked the cylinder walls and nothing looks scarred or ridged.  It has about 100,000 miles on it - but it looks like you could've run it for 10,000 miles and done the same things we did.

What I'm going to do with it-
1. new oil pump.  While we're there, they're pretty inexpensive but not fun to do underneath the truck...
2. new gaskets for pan, intake, valve covers maybe.
3. Edelbrock Performer RPM intake and cam
4. Edelbrock 650-700 cfm carb
5. Longtube Headers

What we're stuck on:

1. What holes do we need to plug - and what sensors do we need to swap?  What sensors from 98 do we have that we have to remove and plug?
2. As far as the front of the engine and pulleys - is it better to run the 98 setup with a serpentine system or will everything from an 85 bolt up about the same pattern and water pump pattern?
3. As far as hooking up to the transmission- what do I need to know.  I've heard the differences are the flywheel and stuff are different because of the 1-piece rear main seal.
4. Is it pretty simple to replace a rear main seal- we figure while we've got it out we might as well do it.

Thanks guys - if you think of anything else we need to do at this point for the swap let me know.  We are not rebuilding it because it is in good shape.  Not removing the head gasket or anything.

[lukieg]

 You need the proper fleexplate.. externally balanced.. never saw a single piece seal leak.. doesnt mea they dont.. just never saw it... distributor with gear for roller cam... vortec 4bbl intake edelbrock makes one.. once you start putting it in you will see hwat needs to get hookes upp... should only be oil pressure and a live ignition source for the coil... ohh and you need an electric pump with likely a regulator... get a weak pump then you can get away with no return line... you can put a softer cam gear on your 85 hei distributor.. and use that.. Its easy man.. have fun!

[9511234]

We were thinking an Edelbrock 600-650 cfm carb on the performer rpm intake.

I think I'm going to use a block off plate on the fuel pump on the block and mount one on the firewall to keep it away from the heat of the engine a little more.

It looks like there is a knock sensor at the bottom - kind of a bell shape, almost like a spinning top - does that hole have to be plugged?

[lukieg]

 There shouldn't be a spot on the block that requires a block off plate.. that carb and intake are good.. just make sure you have a vortec specifc intake.. cant make a standard one fit... looks similar.. wont work.

[lukieg]

 Any holes you dont use have to be plugged! Once you tear into it you will see... its not hard.. but take your time.. is this your first motor swap?

[zieg85]

Rotation of the water pump on the serpentine system is opposite of the other.  The water pump and clutch fan are specific to which route you are going to take...

[9511234]

First timer here.  yes. 

The place where the fuel pump usually is on the block-it's not drilled through, but for asthetics I just want to put a block off plate there.

I'm getting the pan vatted right now and got a new oil pump, shaft, screen, and gaskets.

My big hang up now is finding a cam that is better than stock, but won't require machining the heads - keeping in mind the Vortec is a roller motor.
I'm about to beef up the internet search and start looking.

I'll start locating some of the front mounting equipment for the serpentine belts and a chilton's manual.  I thought I had a CD from 98, but I lost it.

[9511234]

Decided to go with a mild cam, no spring change or anything. 

GM part number  14097395.

I'll have to get the parts and build her up, but this should be pretty smooth sailing from here on out.... now just to get it to pass inspection, lol.