Lots of good builders out there.
There are also lots of good deals out there to be had as well (especially on flatheads right now.)
As more guys in the deep south are committed to the clone deal, guys are slowly letting go of their house "special" flathead engines.
I've picked up several, gone through them, and resold them and made a buck over the last couple years. Sometimes what I get in are the real deal and make real good power from the builder it was advertised as...other times I've purchased engines with a sticker on the blower housing and that's the only resemblance the engine had to that builder EVER.
First, buy from a reputable seller, or the engine builder directly. (ie you want a Dover AAA carb engine, call Jerry first.)
Within the rules, there's only so much you can do, so most professional "national level" engine builders' stuff will be very close on power. Look for a "name" and consider having it freshened either with the original builder, or with someone local to you who is competent but doesn't have the "name" pricetag on his rebuilds. Don't be overly concerned with bore size for performance. Longevity, sure, but also remember that the blocks can always be sleeved for around $125 - $150.
Our used fresh flatheads sell for anywhere from $500 - $950 - much depends on how good the engine is, new parts, bore life, etc.
If there's anything that I can do to help further, please feel free to contact me directly or call the shop.
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Thanks and God bless,
Brian Carlson
Carlson Racing Engines
Vector Cuts
www.CarlsonMotorsports.com
Celebrating 25 years of service to the karting industry
765-339-4407
bcarlson@CarlsonMotorsports.com