PONTIAC Best 305 Rebuild Kits?


Thread starter
Sep 6, 2020
Search Facebook marketplace and find a good running but clapped out body vehicle. Express vans, suburbans, tahoes, caprices, road master, etc with good running 350 engines. Tbi or vortec 350 from about 1991 to 2002. Even high mileage 350s with fuel injection usually have little wear. Buy it and drive it over to do the engine swap.

I bought a 1994 suburban for $500. 250k+ miles. Ran good and didn’t smoke or leak oil. Body and interior were wore out.
This is actually a really good idea.

Now i'm considering a swap, because you took into consideration my previous comment about getting it delivered, making an acquisition of a motor actually feasible. Because renting a vehicle, just to get a 350 for over $1000, that many sellers can't even prove they work, makes no sense money wise.

But if I can find a running vehicle, for a fair price and put a temp plate on it, to take it for an engine removal? I hadn't have considered that road. Mostly because, of the vehicle being certified if I intend to keep it, but on a parts car that's out of the question.

I will take a look at finding a TBI motor, with decent KM on it. Thank you very much, kind of excited to see about 350 options :cool::p
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G-Body Guru
Feb 9, 2014
North Jersey
I live in NJ and I'l take your 305. I'll even offer you 50.00 which is better to you than free. Depending on when you do it, please keep me in mind.
I’m hoping to do it by the summer. Of course I thought I would’ve had it done already. I’ll post it on my build thread when I start getting into it.
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Dec 21, 2020
I’m hoping to do it by the summer. Of course I thought I would’ve had it done already. I’ll post it on my build thread when I start getting into it.
I'm also planning my build now for a summer swap. I was planning on a turn key crate motor as an easy button but I'm looking into this 305 build and I like the idea. I'm not looking for more than 350 hp, but 275-300 would be plenty for an every day grocery getter and I could stick with 87 octane gas. I'm not building an ultimate ride, but rather a cool daily driver.


Royal Smart Person
Feb 18, 2014
Cost wise, most kits I've found are under $1000. Cost of a 350, with low mileage, is starting at around $1500, PLUS the rental of a vehicle, and gas to go get it, when most people selling them, live very far away from myself.
Also, look into sales on the low end GM crate 290hp motor. From time to time it's $1500 US on sale, not sure on CDN sale prices.

It doesn't really make 290hp, crank or wheels because they test it with unstreetable options on carb etc. But a cam and heads really wake them up and... new.

Best bang for buck under $1000 is probably an L31 truck engine,, but even an LO5 tbi 350 can be brought to mid-upper 300a and near 400 lb ft the with heads, cam, intake, carb,, headers.

Much more power than that you'll need MORE frame work, suspension work, axle work, etc.
As for the rebuild reasons, it's because the engine is seized, and has low KM from what I understand, but you are right, the reading could be false, that's just the risk you take with older vehicles such as these ones.
Emphasis added.

With a seized engine all bets are off and you could be looking at MONTHS plus a thousand or more beyond the kit to a machine shop. All depends why and how it seized.

Until a seized engine is out, and torn down, you can't predict what you're looking at but you CAN expect to pay a machine shop. Which also means FINDING a good machine shop,, then waiting for them to get to your work.

At a minimum you probably need reconditioned rods, pistons pressed onto rods, either a polished or turned crank, at least a line hone on bores if not an over bore. Freeze plugs pushed in, so on so forth...

Logistically, until you know how things will be machined you cannot order the right size parts for the engine.

Then you don't know whats up with the heads, so on so forth.

Biggest problem? You already said the guy who sold you the car lied about things and stopped responding. Well, that calls into doubt the engine IMO if it's already seized.

So on the rebuild path you need your buddy to pull the engine, and strip it to its tiniest parts. Then you see the damage, feel the bore with your nail to see if there's a ridge, etc etc. Get then professionally cleaned (hot tank) and magnafluxed if you get that far without finding a dead end. This is a.couple weeks in.

Then shop should report what they find and where they thing things clean up at. Obviously you tell them no if they want a +.060 overbore or turn the crank .030 under because... why would you want to pay for that in a smog 305.

Then wait for the shop to do the machining and resizing/reconditioning rods/crank etc.

Here you may wait weeks or even a couple months depending on shop volume. The best shops have longer waits because they have more jobs and volume.

Once they tell you for certain what the specs are, then you order new bearings, new pistons, rings, etc, and send the rods back to put the pistons on because it's much easier and you know it's right.

You may wait a couple weeks for parts to arrive.

Now it's a couple full workdays worth of effort to assemble things, assuming no headaches - and yes, you may get a defective bearing or other part here or there, its part of the process. Things gets put together and apart a few times to check clearances as you go.

Depending on schedule of the friend, that decides how quick all this is done. If they mess up, and you start the motor to ruin a bearing and put metal shavings through it you've got to start over.

Eventually, you get a complete motor, set the timing on your new timing chain, that you then put in special oil to break in and run a certain way for a while before changing oil and going on to street use.

Yes, lots of steps left out. Read some engine build threads to learn a little more if you're interested because... lots of details and it may be boring to you since you hadn't planned to do the work yourself.

This was a very long way to say I hope your friend has space to safely store an engineless car for a couple months, or you're towing it back home. Cheaper to buy a collapsible hoist/cherry picker and pull the engine where-is than tow it twice, sell it after and get 50-80% of your money back.

TV shows make it look like you just swap the bearings and stuff works properly. Not always so true, and not for longevity. Couple thousand miles later.... BOOM.

If you've got nothing to lose though, pull the plugs and fill the cylinders with marvel mystery oil. Let it sit a few days. Use what they call a breaker bar (very long rachet handle) on the crank to try to turn the engine and free it up inside. Maybe try oiling a few times. Can't hurt things if you're swapping anyways. Search tips on freeing a stuck/frozen engine. You may get it loosened enough to move under power even if not well.

If it does come free, change oil before starting and go through long storage start up steps, the be gentle on gas pedal as seals reexpand, so on so forth...


G-Body Guru
Jan 18, 2018
I think you're better with a swap as well. Not because of the engine or the size, but because of what seized means. Could be rusted stuck, could be a spun bearing or some other mechanical failure that is not a simple swap of parts. So unless you are prepared for a for a full rebuild of the engine you have and machine work a running engine swap is most viable.


Comic Book Super Hero
Jan 7, 2006
Canton Mi
I'm trying to see about options for rebuilding a 305 in my 1984 Pontiac Bonneville.

It's a Chev small block, so nothing fancy.

However, the only reason why I am considering a rebuild, and not throwing in a 350, is to keep things numbers matching.

Any ideas? Cheers!

Welcome to the sight, I've been using Northern Auto for over 20 years - fast, relievable, lets you customize kits, great customer service, and best of all great prices. A 4 door G body will never pull good money number matching or not. Sounds like your mind is made up so I'll leave my 2 cent out. Unsure of your mechanical skills I've great success finding what I need on the net and keeping my builds very budget minded.
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Master Mechanic
Dec 8, 2019
Malibudave hit it.Find a rusted out heap of a truck or van with a 350 in it. If its a tbi, I think(Don't take my word look it up) you could use the in take and distributor off the 305. Not ideal but cheap. If its a vortec you'll need a vortec intake manifold. Fuel pump is the other consideration. Some have mechanical,some just have the bosses machined. So you'd have to get it machined for the pushrod if you wanna run mechanical fuel pump. Or run an electric pump to a regulator.. everything else is the same. Buying the parts van/truck has the benefits you can hear it run and go through gears. Also extra battery, transmission, accessories,hoses,clamps, wiring and everything else your friend will need for the swap....probably. After you've pillaged every valuable part you can, either part it out or call a junkyard and get 100$.I don't know if you've priced machine shops locally but around here its not cheap. You'll probably have 3k in that 305 rebuild. Atleast 2k. If your friend puts it together. He needs a dial indicator and inside/outside micrometer atleast along with probably 10 other special tools to do it halfway right and build a reliable engine. If im being honest i trust a 100k mile vortec 350 i can hear run more then ME building my own engine.Just do a good amount of research before you jump into a decision. This site has tons of info on tbi/vortec 350 swaps in gbodys.Also what kind of vehicle do you have access to? A 350 will fit in more trunks then you think. Also if there's a uhaul, lowes, home depot and Menard rent trucks by the hr. Welcome to the forum and Good luck on your project.


Royal Smart Person
Feb 18, 2014
what kind of vehicle do you have access to? A 350 will fit in more trunks then you think. Also if there's a uhaul, lowes, home depot and Menard rent trucks by the hr. Welcome to the forum and Good luck on your project.
He has a box caprice, I think 88?

It'll easily hold and engine AND even a loose trans or two trans plopped in on a tire as long as it isn't already filled with speakers.

Just needs a hoist to remove, which, again, you buy and resell when done.
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