The General Motors Small Block V8 is probably the most popular engine ever made and the reason for this is because of its long availability window and the stock and aftermarket upgrades you can order to increase its performance. When you are thinking about the small block v8 there is a lot of variety from the smaller but torquey 302 -327 on the bottom end all the way up to small block 350’s that have been stroked to 427 cubic inches. If price isn’t a factor then you can get an amazing amount of performance out of this block but that is the big problem for most of us price always is a factor no matter what you think your budget is.
With this in mind you really need to have a strict plan when you are building an engine or you will end up wasting tons of money or wasting time.
Many people will say start with a crate engine but in doing so you have already given some of the build options over to the manufacturer of that engine. A better way might be to start with a junkyard motor that you know to be low miles and in good condition. But as we said there are an amazing variety of the small block chevy. So what should you look for?
You want a donor engine that has a 4 bolt main because this means its crank will have better support at higher RPM. The next thing you want is a pair of heads that have large valves and large port passages. In this case bigger the better and because of that you might not find what you want in a stock engine. Next you want an engine that has never been abused so don’t buy one from someone that built it up unless you know them and the engine very well. You want to rule out all types of structural damage so you will need the block cleaned and inspected for cracks and problems.
You will also need to decide will this be a street vehicle or is the engine totally track or off road. This decision is important now because it will be a factor in the heads and other parts you buy.
Make Your Decisions Before You Spend
There really isn’t any secret about what produces horsepower and torque in engines. It is the ability of the engine to burn more fuel at a higher rate in a controlled way. So you are thinking what is a controlled way? Well a super charger or turbo charger is much more controlled than nitrous. I personally would never consider nitrous oxide for a street vehicle under any circumstances because you are going to have too many breakdowns and unknown factors.
Is Stroking the engine a viable choice? It could be but you have to consider that just the stroker kit will run you around $1500 not including any machine shop time that might be required so this really isn’t a budget situation. The benefit of stroking a small block vs using a big block is availability because you are not going to find many 427 big blocks out there and all of the third party products. The small block 350 always had more aftermarket options and vendors than big blocks and that is also true for the small block 302 ford and the 340 Mopar. People could afford the small blocks and more were made so more engineers built aftermarket parts for them. And finally a small block is going to be lighter so you have an easier time building your suspension and its going to fit better in your vehicle. However rejecting big blocks in total is wrong because if you want an ultimate engine cubic inches are the only way to get it and you aren’t going to be able to build a massive 500-700 cubic inch small block.
If you are going to be running forced induction such as a turbo or super charger then you need lower compression forged pistons. As a matter of fact if you are building for performance you will want to change to forged pistons so you have to know before you start buying are you going to run a turbo or super charger so you can get your piston compression ratio correct. If you are running regular fuel injection or carburetor setup then you want a higher compression ratio piston. Smaller aftermarket superchargers are much easier to tune and build than turbo setups
Fuel Injection or Carbureted is also a big question for performance but it comes down to are you going to be running a computer or not. For most of us it will be much less expensive and easier to tune your engine with a carburetor but fuel injection and computer controlled ignition makes for a better daily driver.
Purchasing New Or Used Parts
Its not true that all of your parts have to be new if you want to build a good running engine however many of the parts will need to be new to harness the most from your engine.
A Camshaft Kit with lifters is going to be required as new.
A New set of bearings and gaskets for the entire engine should be purchased. Be Careful when buying parts that you are not duplicating your gasket kits unless you want extra gaskets. Buying a full engine gasket kit and a camshaft kit will often come with a lot of gaskets you already have.
A New Water and Oil Pump should not be overlooked. Many people overlook mechanical Oil Pumps.
As for Heads it is a difficult choice on whether to modify better quality stock heads or go with after market heads that have been redesigned with larger ports. Porting can be difficult for the beginner so spending the extra money could be worth it. Whatever you do don’t buy a long block engine and then swap out the heads it will be an expense that will eat into other items on your list.
A new distributor could be very helpful but is not always required when you are looking for 200hp or less if the one you have now has low hours and good bearings.
What Performance Upgrades Provide The Most Bang For The Buck?
When you are trying to produce horsepower the main thing is getting more fuel and air into the engine. If you have a stock engine the best boost you will see is by changing your top end and your cam. You might not even need to think about touching your pistons, crank and block.
By changing your heads you can go with a junkyard head that has bigger ports and valves without going for an aftermarket head which can be much more expensive. Later model 350’s in trucks and vans did have larger ports and valves but you will have to track the right ones down for your build.
When changing your heads you should also change your camshaft with a kit that will allow you to extend the time the valves are open and the height of the opening. This can get technical but better parts suppliers already know the best setup for your head choice.
Intake and Carburetor choice is the next step and you can find good specs on the range that your intake will support and what CFM your carb should be when matched with your camshaft. It is not a difficult choice but if you upgrade the heads and cam it will be a requirement.
These few things can give you 30% or more horsepower and torque and it does not require a full rebuild or a crate motor. If you are looking to double your performance then you will need to start looking at forced induction and you should know this before you start your build or you may buy a lot of parts that can’t be used with your higher performance needs.
Final Note
As you can imagine this how to is not the be all and end all of how to modify your engine but if you are doing it on the cheap there are many things you have to keep in mind when performing your build.
Some people will want to buy a crate motor and be done with it and that is fine.
Others will want to build what they have just to find an extra 100hp which can be an amazing performance jump on a stock 350 that is rated in the low 200’s.
The main thing is you don’t want to waste money no matter which path you take.
You want to define your expectations up front and align that with your budget.
Carb, intake, heads, camshaft are your primary ways to increase horsepower on a budget and selecting the correct donor engine with good heads and low miles means only a few hundred vs a few thousand to get you where you want to go.
Extreme builds with stroked crankshafts bring you into the high dollar range but the performance gain is amazing. It is all about your expectations and budget.