One thing we can all agree on is that golf carts are painfully slow from the factory.
There are few options when looking to increase performance of a golf cart. Lets go through the options that you have and list out the pros and cons of each.
Option 1: Modifying the factory engine/clutches.
Option 2: Big Block Engine Swap
People ask about modifying their factory engines all of the time and on the surface it seems like a good idea, but there really isn't much of an aftermarket for the stock engines. You can look high and low and it will be very hard to find upgrade parts for the factory Robin, Kawasaki, or Yamaha engine. Eventually, you will run in to some options such as head machining, camshafts, clutch machining, stiffer clutch springs, carb tuning kits, high flow exhaust, etc....
The fact is that you can dump anywhere from $500-$1200 into a stock engine/clutches and be lucky to see a 2-3hp increase, yet you still have an old tired engine/clutches and we all know how modifying an engine decreases its lifespan and reliability.
I know you've heard the phrase... "THERES NO REPLACEMENT FOR DISPLACEMENT", and it holds true with golf carts.
When you buy a big block engine kit, you are getting a brand new performance clutch with belt, a brand new engine with double the displacement of the factory one, and a warranty! All this for around $1600-$1800 is really hard to beat!
Are you ready for the icing on the cake?
If your current factory engine/clutches are in running condition, you can sell them for $500-$1000 (depending on condition) via sales sites such as Craigslist, OfferUp, or eBay and offset yours costs. Its not unheard of for a customer to have a total investment of under $1000 in a big block kit.
But wait...there's more...
A professionally manufactured big block kit such as the ones that we design, manufacture, sell and support will actually INCREASE your carts value..why? Because most people use golf carts as affordable utility vehicles around their yard or place of business. A big block kit is a major selling point to those who will need to climb hills or need the ability of a side-by-side at a fraction of the cost.
Home-made swaps are rarely produced to the same quality as a professional kit, and good luck getting replacement parts from "Cleetus, the backyard welder"(forget about a warranty). For this reason, you will (in most cases) get more for your cart than what you have invested in it by doing a big block engine upgrade.