Modifying a 3.5 HP Briggs

Chopped50ford

Chopped50ford

New Member
#1
#1
It appears the 5 hp is popular to modify but what about the 3.5hp engines?

What are some things you can do to boost some extra power from these small guys?

Can you add a downdraft carb?

Mill the head?

Cam changes?

Rod lengths?

Im very curious and I think it would be great for those budget builds; Like mine. :)

Thanks.
 
minibikedude

minibikedude

Active Member
#2
#2
American power sports use to carry some parts for the 3.5 Briggs that were used in Quarter Midets. My old catalog from 2001 shows intakes for different carbs and air filter adapters. and a couple of other things for them. I would call them and see if they have anything still available for the 3.5 Brigss, There in Newbury, Ohio 1-800-262-0555 eastern time zone. Or look at apskarting.com
 
milo raptors

milo raptors

New Member
#3
#3
well as far as i know the only rod piston combo that fits the 3 hp is a modified 5hp stock rod and like a 500 compres height piston now this info has come a ways down the grape vine so dont hold me to it. As far as the cam goes welding and regrinding are your only options. You could mill the head if you shave the eyebrows these litle engine like more flow than any thing not so much copresion . the proper term is and up draft carb and i dough it would mak any more performance maby even less. if its the big tank 3 hp then find a raptor 3 carb and swap the jets or get and equivilent sized slide carburator and manilfold. you could fabricate a header for pretty cep those are a quick wayt to more performance
 
Chopped50ford

Chopped50ford

New Member
#4
#4
minibikedude said:
American power sports use to carry some parts for the 3.5 Briggs that were used in Quarter Midets. My old catalog from 2001 shows intakes for different carbs and air filter adapters. and a couple of other things for them. I would call them and see if they have anything still available for the 3.5 Brigss, There in Newbury, Ohio 1-800-262-0555 eastern time zone. Or look at apskarting.com
Click to expand...

great site, but holy confusing on the website; especially when you are not very familiar with the engines. Too bad we werent talking about Flathead Fords..... :smile: Lots of parts to pick from, this should be fun.
 
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