Need Help On Making More Power For My Flathead??

DRC21

Member
I have a Briggs 5hp Flathead Engine. I Have A Alky Tilloston Carb. ARC Billet Rod, Dont Know The Length. 290 Lift Dyno Cam. Stock Flywheel. Im Not Sure On The Valves. Just Recently Got This Engine With My Kart I Bought And Havent Tore Into It. Any Suggestions On Making More Power?? I Know Lots Of People Are Shaving The Eyebrows. Whats A Good Depth To Go Down Too?? And I Do Know How To Port And Polish. Should I Do That To Intake And Exhaust Ports?? If You Can Help Thanks!!

DRC Racing Team
 

alvin l nunley

Site Supporter
All engines respond very well to more compression, even more so with alky.
Comments, compliments, criticisms and questions always welcome.
 

DRC21

Member
Would you recommend cutting of the eyebrow?? And Should I Just Port And Polish the Intake Port Only? Or Both??
 

keithcar72

New member
compression is king but on a flathead sometimes you have to balance between flow and compression. A lot of what you do will depend on rules and application. 290 lift is pretty small especially for a tilly. there are a lot of gains to be made on the intake side, but don't get carried away on the exhaust. It's already a little to big.
 

DRC21

Member
I took the engine apart and the intake is already ported so im gonna polish them up. Now do you think it be a good idea to shave the eyebrow
 
Cut the eyebrows down to the depth of the top of the valve seats into the cylinder as long as you don't go so deep in the cylinder to expose the compression ring. Use a head gasket as a template when cutting the eyebrows. Cut the cylinder head to a point that it is flat above the cylinder (angle cut to leave as much above the valves as possible). Deck the block to zero (no pop-up), with a stock head gasket you will have plenty quench. Anything you can do to improve the flow helps. Your ports do not need to be finely polished, a little rough promotes fuel atomization. -- Chuck
 

animal 77

New member
I've got a bigger flathead that will get ya going :) blockzilla 3= 3" bore 1 1/2 intake valve and 1 1/4 exhaust it's ready to race, .200 longer stroke lunati forged crank, horstman billet rod, wiseco piston, isky cam, ect. makes around 30 hp, cheap if your interested?
 

kartboy63

Member
what all comes with it and I never had a Waszoom in all my years of racing that is a motor that we just didn't see much in south Louisiana. what makes the blue wazoom different
 
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