Well my goal here is to simply swap in a 350. My plan is to get a hold of a 350 block and swap everything over from the 305, minus the pistons and injectors. I might even try some self porting work after researching enough.

Any advice on what donor engine to look for and which to avoid? Preferably, I'd like an 87+ but were there any differences in the block compared to a 70's 350?

I have a couple offers:
-a 350 block that needs to be bored .060 over for $20
-4 bolt 3970010 casting. needs align bore along crank mains, light surface rust, smogger heads $150
-complete '89 TBI engine minus intake from a Blazer 157K miles $200

If I get a bare block I'll need:
Pistons, Injectors, and a chip from a 350 TPI car. anything else?

I'm doing this on a high school budget so the least expensive route is probably the one I'll go with for now. Any suggestions and tips are welcome. If there's anything I missed let me know.

 

The best shortblock for the budget would be one that doesn't need pistons, rings, or bearings.

The '89 engine sounds promising, depending upon its condition. Your heads would work better than what came on it. Your flexplate wouldn't fit it, but hopefully it has one with it. Otherwise, about a $40 part.

'85 TPI was kind of the bastard of the family. Slower clock speed, no 350 offered with it (in 3rd gens, anyway - I don't know if an '85 Vette chip would work). If you could find an '86-'88 ECM, that would be a step forward. 350 chips are available for them ('87 & '88 - '89 eliminated the cold start injector). But, your ECM would probably do fine with the 350, anyway.

I'd avoid the first two blocks you listed. Too many potential problems.

What condition is your 305 in?

 

if you get a newer block with a one piece rear main seal it should have the provitions so you can run a foctory roller cam. if you wish 87 was the changing year more less i had an 87 5.7 1 piece w no provitions but keep in mind the 1 piece rears run a smaller bolt pattern for the flexplate/flywheel so that will have to be changed as well. if its going in an auto the 89 sound cheap and easest

 

I had my mind on the 89 as well. It is going in with an auto trans for now (700r4) but I plan on doing a T-5 swap by next summer. My current engine is in pretty good condition for 140K miles and no rebuild. I race with it at my work but it's held up with no problems. I'm wanting the 350 for more power, cubic inches and better potential for future upgrades. The '89 engine does come with the flexplate so that wouldn't be a problem. Would this engine be running a different cam than that which came in a comparable F-Body?

 

It's probably a flat tappet cam. It won't be as good as your TPI cam. A good time to upgrade to a better aftermarket cam.

 

it probably would be a flat tappet but a hundered bucks or less and ebay, friends, gm dealer you can make it a roller if it has the provitions to. Just pull the intake and take a look in the lifter vally and see it there are 3 threaded bossed sticking up or look up the casting number that should also tell you, or can post it here and some one else will

 

The casting # won't tell you if it's been machined for the roller pieces. The truck and passenger car engines used the same castings, but trucks typically weren't machined.

Inspection is the only reliable means of knowing. Since the engine doesn't come with intake manifold, it might be a simple matter to go look at it.

I do agree that inexpensive roller upgrades are available. It just won't be inexpensive if the engine currently isn't roller.

 

Well it's not that important that it's a roller engine. What's really important is my ability to gather all the needed parts and make this swap as quick as possible.

 

Well after talking with a a fellow coworker I found out that he knows someone that has 4 turnkey 400 engines for $300 each. I am a bit skeptical though as a perfectly fine running 400 for $300 seems a little sketchy to me. He does have them all on stands so we could hear and see them run. I'll be going to check out this deal pretty soon. I can get more information later but I don't know that much about 400's. Are there certain pro's and con's in the years, castings, heads, intake, etc? I'd really like to stay fuel injected so I would consider running it with TPI until I can get my hands on a HSR.

 

so long as you have an early style baseplate you can run stock heads. If you have to buy a base a good idea would be a vortec and heads and convert the heads to the 400

 

I have an '85 TPI system, Don't know if that's early enough. As in stock heads what exactly do you mean? stock 305 heads or stock 400 heads?

 

Early TPI as in '85 & '86. The bolt pattern changed in '87.

He meant stock 400 heads (at least, I hope that's what he meant). Stock 400 heads are terrible. So, the TPI won't kill it too drastically.

The '85 TPI computer wasn't that great. '86-'89 are better, '86-'88 will work with your TPI hardware.

 

You can use your original knocksensor(if it's working and you can remove it)They used same knock sensor &esc module 305&350 at -85.

 

sorry ment convert the vortech heads to 400 style (stem holes)

 

I'm going to check out these engine with a fellow coworker who is interested in buying one and his brother who is a mechanic. They will be tearing apart these engine to make sure there is nothing wrong with them. I'll be getting a 400 flex plate in order to mate it to my 700r4. I don't really know anything about the engine yet as to what they have for running gear. That is if I do decide to get one.