Cub 100 engine upgrade

Bill Sick · Jul 24, 2023

Hi
we use a Cub 100 basically as a golf cart for swap meets... Because some of the meets are larger and I like a bit of a thrill, I upgraded the pinion and bull gear to the largest available... Ok ,. So it's fun.... About 12 mph on the asphalt with the tires I'm currently running.. I'm thinking about freshening the engine. While I'm at it get a few more revs out of it.... What is needed to get 8n the 4200 rpm range and not lose all my bottom end... What cam? Piston ? Rod compression ratio? Power is always a plus ... So maybe relief and port? I plan on adding taller tires... It will probably never pull so I'd like a long lasting reliable engine with some more revs and power... I'm thinking 16 mph with loose steering will be a bit of a thrill...

mgwin · Jul 26, 2023

Saw a video once online of someone driving a 100 with a 350 Chevy engine on it!

mgonitzke · Jul 27, 2023

A totally stock engine with a steel flywheel will run at 4200 rpm.

But why? 16 mph + loose steering + brakes designed for half that speed + pedestrians everywhere is a pretty terrible idea.

dschwandt · Jul 27, 2023

I love swap meets & shows but being a bit hard of hearing and having to deal with golf carts sneaking up on you in the swap aisles is bad enough.
Especially when you spot something in the adjacent aisle you want to take a quick look at.

kennymorrow · Jul 27, 2023

Find an Alcoa rod and LP head for it, if you want it to be somewhat stock. The forged rod will improve durability and the LP head will raise the compression.

Bill Sick · Jul 27, 2023

I have a creeper gear for the crowded times and areas... Why would I parts shop at 16 mph. There are times ad places for everything and I appreciate your judgement of my amount of common sense... I Guess I should have said...
I want to race my neighbor on his junk Deere on a closed course with our fire proof suits 5 point harnesses full face helmets ... Cause Lord knows a golf cart certainly can't do 15 mph these days.
Thanks for the replies on a slightly touched up engine... Where will I find a propane head ? What is the max SAFE rpm of a steel flywheel engine... I'm not into rebuilding yearly or scattering parts across the parking lot... Aluminum or forged rod? Rebalance necessary? Etc