Stroking a 305

Oddly enough there was a series of articles in a contemporary car crafting magazine during the last six months or so that featured a Blue Oval 302 vs a GM 305 and which discussed the various options open to the two engines. The biggest problem with the 305 is its bore. Being under 4", there is little available by way of performance upgrades. You can swap cams and associated valve train components but the heads themselves are the limiting factor and there is apparently only one manufacturer that evens offers a performance head. The reason for this lack is, as I mentioned a sentence or two earlier, the small bore. Being under 4", you can't use most of anybody's heads because the valves will crash against the cylinder walls. Overbore to 4" is a wasted exercise; simpler to scare up a 350 block and start with that 4" bore. The same restrictions go for pistons and rods and cranks. As someone else mentioned, 334 cid is the biggest you can take a 305 out to. At that point you pretty much have an old school 327 that has been bored around .010" and the 327 is a better motor to start with. If the numbers matching aspect is as much of a concern as you say, then you might give some thought to finding a year correct 350. Your 305 motor is likely to be a Vortec piece anyway; I have one from my Monte that was plugged in by a prior owner and nothing from it is correct for my build. What you would be seeking is a Vortec 350 from any 87 Chev/GM that came with one from the factory. For what I am doing, my mill came from an 85 Chev truck, year correct. That is as correct as I need it to be because this build is not a 100 point special by any means. So maybe a couple of Saturday strolls through your local pick-a-part and see what turns up. Just a thought

I followed that,it was kinda nostalgic actually

I have no problems with 305's; however, stroking a 305 is absolutely pointless. I have a few cruisers with 305's in them, good on gas, sound good and run forever. Reality is: if you want any kind of noticeable performance, you can forget about a numbers matching car with a 305 in it. Spending $3-4k to stroke a 305 and get less hp and torque than a $1,600 goodwrench 350 with a $100 cam makes no sense. If you're bent on keeping the 305, bore it .030 over to clean up the walls, turn the crank, throw a summit 1102 cam in it and call it a day (you'll have about $900.00 into a good running 305 with a little bite to it). Anything more than that, let go of nostalgia and lose the 305. Like one of the other posts said numbers matching with a 305 doesn't amount to $h!t.

Those cheap Goodwench 350s are probably worse than many 305s unless you rip the pistons out and put in higher CR ones along swapping on smaller chamber heads. Smogger 350s with 8.5 CR and big chamber heads = pure yuck. Not all 350s are better. Bigger cam won't help them much. Yes they are rated for 260 hp, but they really are 190 hp van motors. At least the later 305s have 9.5 CR making them good utility motors.

If one wants to rebuild a 305, go with 9.5 CR HO spec rebuild and use 059 L30 Vortec heads that are 58cc. Good source for them is Mercrusier. Get a decent cam like a Crane 2040 and be done. It will be a decent cruiser engine.

No replacement for displacement

Ok, I actually built a stroked 305. So long ago, I had to wait 6 months for PAW to ship me a cut down 400 crank. Yes, that long ago. I paid real money for a 400 crank cut std/.020 to fit my 305. No one had long rods either so its got a set of pinks in it. After I sourced the 400 flexplate and balancer in it went. Compared to what it was, I was happy. I was also 23 and you could run faster than most new cars. It had a nasty vibration at 3000 RPMs too. Probably a function of the short rods and the awful side loading that thing has. Keith black will sell you some hypereutectics with the wrist pin moved so that you can run a longer rod. No, it will never breath having a small bore, so add a good set of heads with small valves and a decent cam and you will notice a difference.

Now, everything everyone has said about it being a bad idea is true. It will cost you more than a 350 build and not perform as well. But if you want to do it, get the long rods and the KB pistons, some Vortec heads and good exhaust. Definitely add gear. It will be fun and sort of numbers matching. Also, you need a real carb and distributor. the computer controlled ones will just inhibit any gains you think you are making. then throw away the 75 miles of vacuum hoses you have under the hood. You will have removed all vestiges of the "originality" of the car. So maybe the 350 is the way to go.

Were it me, I would clean the piss out of the underhood. Freshen up the 305, put a gear in the car and some real exhaust and drive it. The gear has been mentioned earlier and its the best answer. It will give you the most in the seat of the pants which is really what its all about. How big do you smile when your tires make smoke. Most of us on here remember when 300 cubic inches was a small motor and displacement ruled the streets. Motors were measure in cubic inches and a liter was something those silly Canadians measured their gasoline by. You live in a different reality now. 5.0L is a big motor and everything is DOHC, turbo charged and makes 100hp per liter. Us "old" people cant understand how you "young" people think. Back in the day, the 305 was suitable as a boat anchor only. In reality for what it was it wasn't too bad.

So, about the 334 (stroked 305). I have no intention to ditch it. My 84 is on a rotisserie right now. The motor is in a bag. I intend to put a tuned port on it, build a mega squirt controller and boost that b*tch. I will ditch those short rods, get some 5.7's and those fancy pants KB pistons and a nice set of aftermarket centerbolt heads with small valves. Why? because Im not smart and more importantly why not. Maybe Ill learn something. Maybe I will waste a lot of money, but hey If I had all the money I spent on cars.......

My El Camino currently has a high output Camaro 305 with a one piece rear main and 416 305 ho heads ported and polished, 9.5 compression piston's, comp cam 268xe cam with matching springs with Roller rockers. I actually like having the 305 with all the upgrades I did over the 350 crate engine ,and 383 that were in my El Camino before it got the 305. I would definitely say rebuild your 305 and be happy with your gbody that way you want it.

87grandprix84 said:

This is my daily driver and I really don't want to have issues like overheating ect. I've never rebuilt a car engine before either and was curios how stroking it would effect compression ratio as I'd like to continue running regular 87 to 89 octane.

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I think since the OP apparently has no real aspirations to have a big increase in power and seems to be more concerned about the "numbers matching" aspect of his engine and also has no experience building an engine it seems to me the best route would be getting a stock rebuild done by a shop with maybe a mild cam upgrade.
I think to keep a stock 84' 305 SBC numbers matching by retaining the original block and heads but spending money on a stroker kit is a waste of money between parts and labor and the limitations you would have keeping the stock heads and of coarse the fact that even at a .030 overbore it is only going to have a 3.77 bore, far from 4.00 bore with most small blocks.
In the end a lot of money will be spent for minimal gains, so I would use the stroker money and put it towards getting a more rear gearing and a better exhaust etc.
For me I am just happy I will never have the restraint to ever keep one of my cars "numbers matching".

My second car was a 65 GTO with a 389, three deuce setup. I wanted to keep the car numbers matching but for a putz who didn't know squat about motors, keeping the three deuces running right was beyond me. Also, EVERYBODY in my neighborhood was running BBCs. I was complaining to the guy who worked on my car about wanting to keep the car numbers match but wanting the BBC too. I was 18 and he was like, really old, maybe almost forty or so. Any way, he shook his head and actually slapped me on the back of mine. He said, "Stupid *ss, take the 389 out, put it on the side and put the big block in. When you get tired of the big block or want to sell the car, put the 389 back in." So that's what I did. Who new old guys were so smart!! Of course I worked all summer and every weekend for a year before I bought a nice 396 325 hp with about 30,000 miles on it and put it in the car.

In your situation you could pull the 305, put in a 350 with a few mods and still spend less money than you will trying to heat up the 305.

Just a thought.