Need To Do SOMETHING about my Engine soon, please help!

[pcguysam]

Ok guys, my old 305 in my 81 is drinking oil like it's at a wedding with an open bar.  I have been researching my options and I have such tired head, but this being my first build, I know that it is an important decision that I want to get right without unnecessarily blowing cash.

Options -
1) Replace 305 with a rebuilt, reman stock 305.  Because I have the core, this option cost me $820+tax
2) Replace the 305 with a rebuilt, reman stock 350.  I do not have a core, so this costs me $825+$340+tax
3) Try to find a 350 block somewhere, have it bored to .030 over and build a 383(I have no idea what this will cost)
4) Insert whatever big block, other block, mopar, yada yada option here.

Option 4 is probably a no go just purely on unknowns.

I have been searching.  I have found all kinds of information about Gen I vs. Gen II vs. Vortec...  My natural inclination is to go with option 2, however, when those ponies start prancing in my head and I think of the growl and grumble of 400HP of the 383 vs whatever the stock 350 is going to make, I get really conflicted.

Now on to my questions...
The main difference I can find between the Gen I and Gen II 350 5.7L blocks is the need for an electronic oil pump versus mechanical?  Can someone verify this?
Can I use a Vortec or Gen II block with a carb and Gen I heads or does it have to be Fuel Injected?  I have learned the difference between the Gen II TBI and Vortec injection.

Basically, what kind of trouble am I getting myself into trying to put a newer motor into my '81?

I apologize in advance, but I am a complete mechanical novice.  I am learning and I will have lots of help on the install.  I just need to know what my best option is.

[jhuethk20]

Go with the 383 , I'm about to start one myself for my 76 k20

[Fairlane514]

A lot of it depends on the purpose of your truck. 383 may be nice but not necessary, if you are looking to save some money.

Vortec.....no you don't need an electronic oil pump, I think you mean fuel pump. Some Vortec blocks have the provision for a mechanical fuel pump, I found one recently and I am doing a build with gas milage and torque in mind.  Vortec can be carbureted, but you will have to use a Vortec specific carburetor intake (not hard to come by). You will also have to get the one piece rear main seal flex plate (cheap).  Definitely use the Vortec heads over the Gen I heads.

Vortec does not require any electronics if you go with a carburetor. All your accessories from your 305 will bolt up to it, HEI distributor and old school balancer will work.

[pcguysam]

Ok, so don't take the butcher's word for it.  I climbed up on top of my motor and looked at the casting # on the back of the block and guess what!  It's a 350 with the famous 3970010 casting #.  SO, this means that I can swap it for a remanufactured 350 for $835 without paying the $340 core charge.  Great news there!
After much consideration, I decided just to go with the stock remanufactured 350.  Reason, the price is really good and the machine shop doesn't warranty their performance motors because "I can't warranty that right foot of yours."  Plus this is going to be a daily driver for me for awhile.  And if I decided to build a 383 later on or do whatever I want to with this one, I still can.  I'm going to pick up the new one on Friday.

:-)  Happy guy today

[pholliday1]

Just keep in mind all the "small" extra exspenses
 
oil
antifreeze
exhaust hook up?
plugs
wires
distibutor
Little things can add up fast good luck keep us posted!

[Engineer]

When I read option 4 (Mopar) I almost swallowed my chewing gum. *GASP*

[gildardo01]

When I read option 4 (Mopar) I almost swallowed my chewing gum. *GASP*

haha... i thought it was funny... first thing that came to my mind was 6.4L HEMI...

[pcguysam]

Just keep in mind all the "small" extra exspenses
 
oil
antifreeze
exhaust hook up?
plugs
wires
distibutor
Little things can add up fast good luck keep us posted!

I know.  Already been thinking about those things, water pump, etc...  Regardless of what extra expenses I might have, at least I don't have the $340 core.  That was the part that I was having a hard time swallowing.

[pcguysam]

When I read option 4 (Mopar) I almost swallowed my chewing gum. *GASP*

haha... i thought it was funny... first thing that came to my mind was 6.4L HEMI...

LOL!  My point in mentioning it was because everytime you start talking about replacing and engine, you get to hear from the guy whose uncle shoehorned a 454 into an S-10.  That's great and all, but at this point, my goal is to keep this as simple as possible.  This truck is my daily driver for now and I need it to run guaranteed even if I do have the dash dismantled or the bed pulled apart at the given moment.

[bluetarger]

You can build a very economical, very strong, very reliable 350 with Vortec style heads. This has my vote. There will be some additional considerations while building the engine to accommodate the Vortec heads (intake, and cam lift limitations) but mid 300's for horsepower and high 400's for torque should be fairly easily achieved without much money spent.