If you have an Instagram account, you might have seen or follow H&H Flatheads. The La Crescenta, CA engine shop started in 1972 founded by Mike Herman’s father. Mike has been running the business for the last 14 years working on all sorts of cool and unique builds, specifically flatheads. Since taking over as owner of H&H, he bought Navarro Racing Equipment 11 years ago, which makes all the heads and intakes for flatheads. And three years ago, he also bought Sharp Speed Equipment and Austin Speed Equipment.
“I make over 50 different parts and 14 types of heads for Lincoln 337s, V12s, flatheads, and about 30 different intake manifolds for flatheads,” Herman says. “It’s quite a bit of product.”
Some of that product saw its way into a rather rare ’46-’48 Dixon motor that Herman was working on just last week. Dixon is similar to an overhead valve conversion but only for the exhaust, so the intake is still in the block, according to Herman.
“I’ve only built one of these prior,” he says. “I think there are only three of these running in existence. It’s a pretty rare engine and it’s pretty neat looking too. It looks like an overhead engine and the heads are nice and thick, but it takes a stock flathead intake manifold. It’s a real different-looking engine for sure.”
Herman doesn’t believe it made any land speed records, but there are early pictures of it being raced at Bonneville. This build is for a customer of his, but Herman wasn’t given any particular guidelines, which for an engine builder can mean you get to have some fun with it!
“The customer had the heads and the intake and I supplied the rest,” Herman says. “I have over 500 cores here and I picked the very best one to go at. The customer wants to put the engine in a ’32 roadster with a stock transmission, so it’s a real traditional looking car. It’s going to be gloss black and no polish, so it’s going to be a no frills sleeper hot rod.”
While the motor is on a ‘46-’48 block, Herman added a SCAT stroker kit in it, and on the exhaust ports he added plugs for pushrods to get rid of the entire valve assembly and also put a custom plug in there.
“Internally, we are using a SCAT rotating assembly with the crank and rods, Ross Racing pistons and an Isky custom ground camshaft because the exhausts are rocker arm and the intake is direct,” he says. “We have a vintage style magneto that’s going to go on the front similar to a Harmon Collins.”
Despite this being a rare engine, and Herman only working on one other similar engine prior, he didn’t hit too many obstacles with the build.
“I’ve already done one, so I knew how to put everything in,” he says. “Half of the motor is straight forward, except you have to put the plugs in the exhaust ports, which I’ve done before and it’s not that much extra work. Tuning it is a little more difficult than other engines might be, but other than that it’s a straight forward, great running, different style flathead engine.”
Aside from the SCAT rotating assembly, Ross pistons and Isky camshaft already mentioned, Herman used all Manley valves, Isky springs, hollow body adjustable lifters on the intake, and a high volume Melling oil pump. He also used brand new Stromberg 97s from England, a Powermaster alternator and starter, and a McLeod flywheel and pressure plate.
“We test run our engines on a stand, and this engine should make around 225 – 230 hp with torque of 250 – 260 lb.-ft.” he says. “A standard stroker motor with this configuration gets about 200 hp.”