I'm in the planning stages of building a flathead for a Model A hot rod. Don't know much about them (which is why I decided to go this route). From my research, it seems it best to go with a late 8ba. Since everything will be replaced, with performance products, it doesn't really matter whether to go with Ford or Mercury.
I'm looking to get as much hp as possible being normally aspirated. So I'm going for the Scat 304 kit.
One question I do have is the publications. I see a lot of books out there on the flatheads but I don't wanna buy them all. What's the common census on the best rebuild/modification book?
Thanks
Hi (first name), just a couple questions and a few recommendations.
Do you have a "targeted" HP number?
Do you have a "targeted" budget?
1-I would most definitely avoid the Scat line of cranks but do use their conn rods. Eagles balance-up much easier, have had issues with Scats entire line when balancing. Aviod the Eagle conn rods however, they're a tough fit! For these reasons we put together our own kits.
2-I would stay at the 3.312" bore x 4.250" stroke, no larger, not really that necessary and risk having extra "thin" cylinder walls.
3-I would pin the heads and gaskets to the blocks with some .312" SBC dowel pins, extends head gasket life.
4-Modify the oiling system for full-filtering.
5-Drill the lifter bores to help with adjusting the lifters.
6-Try to find a shop that uses a block-plate for finish honing the bores.
7- If you're "chasing" HP I would use ONLY a metric (1.5, 1.5, 3.0) ring pack, these are available from Ross pistons. There are now new pistons available from Icon, also nice pieces but use a 1/16" x 3/16" ring pack. The metrics would be first choice for power.
8-Many other options, some we like: stainless valves, bronze-lined guides/Viton intake valve stem seals, "original" OEM Johnson adjustable tappets, Fel-Pro gaskets, Neoprene 1 pc front seal, aluminum heads (most times Edelbrock or Offy's). I would use Isky's valve springs on this type build.
9-One of the most important recommendations (here anyway) have it dynoed, it could avoid many headaches for you in the future, plus the "moly" rings will be seated by the time the testing is finished. We will no longer assemble any Flatheads without dynoing it, we still do a few with the machining only where the customer walks out with the pieces and does the final assembly himself, but we don't recommend this method.
10-Pre-assemble/check the valves and springs/spring heights to make certain there will be no issues there later. This is an important area to know about well ahead of time.
Would also use some ARP main studs & head studs to hold it all together!
Thanks, Gary in N.Y.
P.S. With many of the builds we've done (dynoed) with a sort of "limited" budget, we find 150/160 HP and 250#/260# Torque to be some nominal numbers. The pistons/rings are a huge factor in freeing up some HP. The ride in my signature has over 30,000 trouble-free miles on now. Dynoed at 155 HP and 264# Torque, this ride must be close to 4000# driving??
