I bought a 91 Camaro RS back in February. I was told it was a v6 5speed converted to a v8 350 5speed. I ran the VIN number on the dash and it said my car was originally a v8 305. I'm debating if my car is really a 350 or not but it certainly has more power than what I would expect from a 30+ or so car with the 305 v8. Any ideas on how to check besides pulling the heads and measuring the bore?

 

Suffix id and block casting number behind the drivers side head.

 

Would I have to pull the head or could I simply find the casting number while the motor is in the car? I'm new to all of this.

 

Or pull a valve cover and get #s off the heads. If it ends with 187 its the stock 305. 191 or 193 its stock 350 TBI engine and a lil better.

 

Ok, so next question. If my car is a stock 305 what would be the best upgrades be to improve its performance and hp. I'm not looking to do an engine swap just want to know whats the best performance upgrades for a 305 or 350 engine.

 

Good tuneup first. Then headers, full 3in exhaust, 342-373 gears +posi.

 

just find the casting number or suffix .

 

The casting number is on top of the block, just behind the driver’s side cylinder head. No need to remove anything, but may have to push a wiring harness out of the way to see it.

If you are looking for more powrformance, As was already stated, if it’s a stock TBI 305, exhaust would be the first thing to upgrade. Also, the stock air cleaner assembly is very restrictive. An open element flows much better, but draws in hot under hood air, still should be a net gain though. If you can get your hands on an 83’-86’ dual snorkel air filter, that would work very well, but they are hard to come by and expensive.

 

I've already taken off the stock air filter and tube and bought a Spectre aftermarket air filter. As for the exhaust, it runs low to the ground which I'm hoping to change by making it true dual running out the back with a Hi-Flow cat on both pipes or running side exhaust but till then I've just taken the end part off to make it a little louder but not much. However, I've found out it's a stock 305 since I took off the valve cover and the end digits I've found was 187. I'm looking to upgrades heads to TrickFlow 175cc or 195cc heads or the AFR's 195cc heads just not sure what's the best for it right now so any info would be appreciated.

 

There really isn’t room to run true duals and do it well and doesn’t make enough of a difference. A single 3” (stock is 2.25” for your car) will flow plenty for that 305 and even a 350. There are lots of header/y-pipe setups and cat-back exhaust setups that will work well. You could start with the 3” cat back and do the headers and y-pipe when funds allow.

As far as the heads, I honestly wouldn’t spend the money on a 305. Do the bolt ons that will transfer to a 350 and when you are ready, do the 350 swap.

 

Cai makes more power, might want to identify what you have then plan a build. I wouldn’t do much without going t56 or tko .

 

I know it's hard to do true duals on my Camaro as for how it's ran from factory. As for swapping out motors I wanna keep it an original motor so with it being a 305 I was hoping to keep it that way. Just rebuild it again and while doing that add power adders to it. My brother's 90 Foxbody GT is the 302 but it has been rebuilt and built fairly good to be keeping up with a 2011 5.0 Coyote which is tuned and pushing close to 500 hp. I'm not looking for a all out drag car. Just something to be quick and at least keep up with the fairly new mustangs and look good at car shows or Camaro meets (which if you know of some around Alabama that's happening in this year still I would be interested and maybe getting info on that) If I have to I will do a engine swap but instead of a 350 I was thinking of a 327, our 78 c10 has a 350 and it is absolutely terrible on gas and speed.

 

You’ll spend the same amount of money rebuilding a 305 that you would a 350 and have less power. It’s just not worth it. Gas mileage will be the same. There really is nothing special about a 327 either, but in this case it’s harder to come by and is old enough that is has so many differences to your 305 that very little will transfer over and will be a huge hassle. A 305 or 350 from 87’-95’ (non-vortec) would be a direct bolt in.

If it were me, I would do the exhaust and leave that 305 alone and just drive it for a while. Later, I would get an L31 350 Vortec crate motor and a Vortec TBI intake manifold and drop it in. Way easier, more reliable and the same cost or maybe even less than rebuilding the 305.

 

What's the difference between the Vortec 350 and a regular 350? Specs of both engines and which is cheaper to build? Also would my 305 tbi setup (intake and throttle body) work with either one and where can I find a aftermarket intake and tbi for it. I've searched and searched and can't find any aftermarket ones that'll work for mine.

 

L31's are cheap, plentiful, and have 4bolt mains instead of 2, so they're stronger than your traditional 2 bolt mains 350's. Compression is usually 9.4:1.
Both 305, and 350 would cost the same effort to build up, but the L31 can easily surpass 300+hp with less money. If you add the same type of mods and effort to a LO3, you'll only see 225-250hp max. I'm not saying that it's impossible to make serious HP with an LO3 (I've seen some pumping 400hp), but those people have very deep pockets and different needs to run a 305. For an average modder (like you and i), the L31 will not disappoint in terms of power, and money.
Yes. You may use your LO3 tbi setup, but its too restrictive to make decent gains.

There's a lot of info in this website on how to build a decent L31. You just gotta search.

 

L31 as in the Vortec 350? Where would I be able to get a cheap one for around $500 or would I be able to get one for that price? Also, would it bolt right into my car and would I be able to use my transmission and wiring harness or would I have to get a complete new setup?

 

Yes, that’s the one. They were pretty standard in 96’-00’ full size pickups, Tahoe’s, Yukon’s and Suburbans. Probably could find a good running one for under $1K. There are remanufactured versions out there for around $2K and new GM for $3K. The benefit of the L31 are the Vortec heads. They are an excellent flowing head for stock production, that’s why they are so popular. The problem is that they require a specific intake manifold. Yours won’t work. GM Performance makes a manifold, but it’s pricey (about $550).
https://www.gmperformancemotor.com/parts/12496821.html

You could look into finding an 87’-95’ 350 motor from a pickup, Blazer, Jimmy, Suburban. Your intake manifold will bolt right up, but those motors have the lower flow swirl port heads (as does yours).

However, if your budget is $500, and if your 305 is running good, don’t do a motor swap yet. You will spend that just in support parts (belts, hoses, gaskets, plugs, wires, etc.). Wait until you have more budget to work with.

 

My 305 in my car right now was remanufactured at about 130 or 140 thousand miles and it currently has 224 thousand miles on it now and it is still running fine. Haven't had a problem with the motor, in fact, it acts as if it was just now rebuilt. However, I know of a guy with a c20 I think square body chevy with just a block that I think is a 350. It's only the block though with nothing else. Would it be wise to get that block and rebuild it and drop it in my car.

 

Maybe, if it’s a good running motor complete with cylinder heads and it’s an 87’ or later. If it’s an 86’, the block is the same, but the heads are the older style and won’t bolt up. 85’ and earlier is the older block with a 2 piece rear main seal and the older heads, so I wouldn’t use that. If it’s something that needs to be rebuilt, then I wouldn’t bother. You can get a new or reman L31 crate long block for similar money.

Sounds like your 305 runs good, so that’s a good thing. Go after all of the supporting stuff first (headers/exhaust, rear gears, you already have the cold air intake). This stuff will make a big difference in performance, sound and feel for the least amount of money and will all transfer to a 350 if you choose to do that later.

As an example, years ago my brother had a 92’ RS 305 TBI/Auto. Stock it was pretty slow and boring (mid 16’s 1/4 mile). We did some upgrades on a tight budget that made a big difference for the money. 1/4 mile dropped to low 15’s (still slow, but much better) and the car was a whole lot more fun to drive and sounded good. We never pulled a valve cover or otherwise went into the motor. A 350 swap would have been the next step, but then he sold it.
-Open element air filter
-Bumped base ignition timing from 0 BTDC to 6 BTDC and ran 93 octane
-180 degree thermostat
-200 degree fan switch
-TPI/305HO exhaust manifolds & y-pipe (couldn’t afford headers and they were free)
-Flowmaster 3” cat back
-3.73 rear end from an 84’ T/A
-Shift kit

These would be all things that I would either ahead of or in conjunction with a 350 swap in order to realize the benefit of the bigger motor, so makes sense to do them first. They will help to wake up the 305. It’s just not worth going into the 305 to do any performance upgrades.

 

How much money do you have to spend? What's the budget here for upgrades?

GD

 

Not a big budget, I'm only 16 without much money. I thought I'd just get a general idea of what to do.

 

Glad to see a new generation interested in these cars and you are asking good questions. Been there myself once upon a time with an 86' Iroc I bought when I was 15. Honestly, I think the only thing that kept me from going overboard on modding it way back when was my lack of funds. The car remained relatively stock, other than a catback exhaust, but I had grand plans for building a motor and lots of other hot rodding. Looking back, it was a good thing that I left the car alone and just drove it.

Best advice I can give you is first and foremost, prioritize safety and reliability of the car (i.e. good brakes, replace wear items, tune up parts, etc.). It's an old car, so keep some cash reserves for things that break (and they will break when you least expect them to). Then, when you have a little bit of extra cash above and beyond your reserve and fixing necessary things, then take on performance improvements one at a time, moving up in complexity and cost as you develop your knowledge and experience. A good 3" cat back exhaust would probably be the next upgrade on my list after the air intake you already did. There is also nothing wrong with leaving it alone, but I get the itch to do some hot rodding.

 

I am planning on getting a better exhaust system but I'm not sure which is best. I love the sound of a true dual straight pipe but I have no clue how to run it. That or a side-exit exhaust with Hi-Flo cats on it. First off I'm trying to find headers or a way to get rid of the smog pump without the delete pully.

 

Lots of options out there for exhaust, just personal preference on sound. I personally like Magnaflow. Same configuration as stock, single mid pipe, cross flow muffler with dual outlets. You could remove the cat and smog pump, but I would leave them. They don’t hurt horsepower and it keeps the exhaust from stinking. Does this car need to go through emissions testing in your state?

When it’s time to do headers, get the 3” y-pipe and 3” converter and connect it to the 3” catback.

 

Engine upgrades/builds are very expensive, even if you do the work yourself. To farm it out to someone else would cost an order of magnitude more.

If it's running OK now, drive it and enjoy it for what it is. Start saving your $$$ if you're serious about building an engine. In the meantime, learn how to perform the car's regular service operations (oil changes, brakes, etc) to increase your experience level.

 

You should drive it as-is. Trust me you cannot afford to do anything that will be a significant performance improvement. For one thing any changes you make will require tuning and that alone puts it beyond your budget and experience level.

GD

 

No emissions testing here in Alabama.

 

I already know most basic mechanic skills, as my brothers and I are crazy about cars and fixing them. I've generally have already done repairs on my Camaro and my 03 Dakota. Also my 78 C10 350 I have done tons of work on that. However, I do agree on the saving money which is what I'm trying to do it's just hard with so many tempting projects for sell.

 

In that case, you're way ahead of the curve for your age group. Stick with it, and learn all you can about everything mechanical/electrical; it will serve you well all throughout your life.

For most of us, the $$$ aspect of hot rodding is always going to be a primary factor in what we can do/what we can accomplish. Just have to be persistent in achieving your goals over time.

 

I am, I've talked to my brother too with a built 302 Foxbody as he knows more than me on cars and motors. He finally convinced me to do an engine swap later on. Said for my car right now he'd put a good cam in it, full exhaust upgrade, and do general care for it till the motor goes and for me to save money and buy an LS so I guess I'll do that? I will have more questions later on though about rear ends and transmission and all that good stuff.

 

I wouldn’t do the cam in the 305. Save your money and efforts toward the next motor. Exhaust is ok to do, but if you might go LS instead of SBC later, don’t do headers now. They won’t bolt up to an LS.

 

LS is the 5.3 isn't it or am I mistaken? Has anyone tried to put a 5th gen motor, say the LS3 or L99, in our cars? is it even possible?

 

LS is a bit of a generic term for the generation 3 and 4 small block Chevy. It started with the LS1 5.7 liter in the 1997 Corvette and that’s how it became known as the LS-series of engines. The 5.3 truck engines are LS-based as are the 5th gen camaro V8 motors. Late 90’s/early 2000’s are going to be the easiest swaps. An LS1 from a 98-02 F-Body is the most straightforward. A popular alternative is a truck 5.3 from the same era since they are plentiful and cheap, but then Truck-specific parts need to be swapped, such as the intake manifold to an LS1 or LS6 from an F-body or Corvette. I believe the accessory drive is different on the trucks as well, so an F-body setup (maybe Corvette, but not sure) may be needed.

There have been many swaps of all different LS motors into 3rd gen fbodies. Peruse through the engine swap sub forum and you will see lots of discussions on the subject.

 

Thanks, I'll look through pull-a-part to see if I can find any 5.3 motors around. Should be easy to find one where I am.