Build a 308 hudson

49hudsonrod

I recently just bought a 49 Hudson commodore with a stuck engine, but the body is perfect. I want to build an old school hot rod with a supercharged and stroked 308 hudson. I would like to stroke a 308 to 5” and maybe bore it out, a race cam, 7x valves, ported aluminum head and block, with 0.5 head studs, split headers, four barrel carburetor, and a Paxton supercharger. I am sure there is some stuff I am forgetting, so feel free to pitch in some ideas. The problem I am having is finding any information and sourcing parts especially on stroking and boosting a hudson engine. Any information or build lists would be great. Thank you.

Glowplug

Rudy Bennett, Russ Maas, Dany Spring, Chuck Vorse ... bring forth the answers this fella seeks! ?????

Ol racer

Briefly, almost everything you would like to do to a 308 can be done at 20th century Hudson. However They are temporarily in process of moving their Shop to another facility. They sell all those Hi Perf parts to have a local Machine Shop modify your block and/or they completly build modified Hudson Motors for customers all over the World.   Today, Turbo charger is better than a Supercharger.7X Valves with a wide relief matched to Head Gasket and Intake Ports matched to gasket with Cam & Headers make a large improvement economically... Going larger Mod's from there makes lot more HP & torque, but gets costly.

49hudsonrod

Is there still parts available to bore and stroke these engines or does it have to be custom made?

54coupe

Most of us do welded stroker cranks. I know of one billet 5" stroke crank that was made, but it is cost prohibitive for most of us (thousands). The last welded stroker crank I had done was in the $1000 range, and it was 20+ years ago. Stock rods are forged, and of good quality. Pistons will probably have to be custom made. If you go with a 3-7/8 (.0625 over) bore, you might be able to use a Chevy 283 piston with a custom pin height. 21st Century is the go-to here. I think they have built more of these than anyone. Building a Hudson engine isn't cheap. I would expect to pay 6-8 thousand for a turn key stroker, race engine before the added cost of the paxton supurcharger. I have never priced them, and have no idea what they cost. If you decide to build this car, please start a build thread here, and post lots of pictures. Good luck to you.

50C8DAN

Uncommon Eng. in Indianapolis builds probably the most radical flatheads anywhere on the planet.  Here is from their website and you can get one starting at $7K!

7X+  308 Hornet Engine Exchange or Outright  

These exclusive rebuilt engines include modern oversized Manley Stainless Steel 1.647 oversize dia. ex valves, huge 2.00" SS INT valves, hard exhaust seats installed for unleaded fuel, new valve guides, special modern large diameter valve springs and retainers, ARP 190,00 PSI connecting rod bolts, three ring  Forged Pistons with tool steel pins, Cloyes True Roller Timing set,  7X+ exclusive grind special performance cam of your choice (cams ground for automatic or manual transmission usage, smooth or lopey idle), block / head changed over for 1/2" Gr8 head bolts and Gr 8 washers, and includes the new wide and shallow high compression / high turbulence relief developed exclusively for this application! 

Ports are cleaned up on the short side radius and gasket matched, and each relief is hand finished just like the originals.  Additionally, each block is thoroughly cleaned, blasted, bored, CK-10 honed, and decked. Cranks are checked for cracks and main and rods journals ground and radiused for additional strength. Heads are resurfaced, or exchanged* depending on desired compression ratio, subject to availability and condition of core.  New main and connecting rod bearings. 

Stroker cranks  (extra cost) available for displacements up to a whopping 362 tire churning cubic inches!   

Don't waste money rebuilding your cherished Hudson engine with components that won't stand up to unleaded fuel or high performance driving.  55 year old connecting rod bolts, Morse timing chains / sprockets, weak and surge prone valve springs, stamped retainers, cast pistons, undersized head fasteners, and lack of hard seats are notorious problem areas!  Eliminate them all during your rebuild!  Your investment is appreciating, treat it to the finest rebuilt engine available for Hudson's today!

 *Aftermarket connecting rods, stroker cranks, exchange heads, align honing, CUSTOM billet cams & oversized hard chromed tappets, dry decking, and other special vintage racing mods are available at extra cost.

Offered Exchange or outright, (exchange must supply rebuildable core, block, crank, head, cam, and connecting rods, unservicable parts subject to minor addl. core charges)

Reaming Hudson Rod for ARP 190,000 psi Rod Bolts

The 7X+ 308 Hornet  (starts at)  $7000     

 

 

49hudsonrod

I would like to make 400+ hp out of this engine. To make the money worth it. Is that an achievable goal with this set up, or should I just freshen up an old engine, beef it up, and slap a blower on it and be happy?

50C8DAN

I would call Uncommon and ask them, they are probably the few that have gone that high up in HP and outside the box engineering.  362 Cu In in a flathead inline 6 is really out there.  You are asking for a significant amount of HP out of this engine.  Remember there are limits to what you get for each mod.  He probably would be the only one that could answer that question.  As said Turbos are the way to go for the most power.  





Stroker Crank 

357 CUBE HUDSON 308 7X+ Maximum Stroker   THE ULTIMATE  HUDSON  "STREET"  ENGINE

• .090 OVER  FORGED PISTONS

• UNCOMMON BALANCED STROKER CRANK

• HARD EXHAUST SEATS

• MANLEY CUSTOM OVERSIZE STAINLESS VALVES

• TRUE ROLLER TIMING CHAIN W/ DEGREE BUSH

• CRANE BIG DIAMETER VALVE SPRINGS

• UNCOMMON MACHINED RETAINERS

• PORTED

• RELIEVED

• ARP ROD BOLTS

• 1/2" HEAD BOLTS

• SPECIAL MACHINED HEAD FOR VALVE CLR

• ISKY CAM

• BIG MUSHROOM TAPPETS

• ALUM / BRONZE GUIDES

• ALIGN BORED AND DECKED

• SPECIAL OIL PUMP GEAR

THE HUDSON 8X  328  RETRO FUELIE  ENGINE

THE SOON TO BE KING OF THE NITRO FLATHEADS, YOU COULD WIN IT ALL AT THE ANNUAL COLORADO INLINE AND FLATHEAD FUEL NATS.

50C8DAN

Here is one even more radical

The Magnificent 9X Hudson's NASCAR  Engine,  Brought up to dateUncommon Engineers the Most Sophisticated Vintage Racing Engines Available Today.  Affordably.\9X Eaton Blower, Intake Log, Headers, Carb Plenum9X Final Assembly, Wiseco Pistons, Manley Valves, Special Moldex 7 Main Bearing Crank, Oliver RodsRear/Top View Uncommon Headers & Log ManifoldFabricating Eaton Series II Blower Plenum, Flanges, and Log Manifold  Modified Series II Eaton Supercharger, Dry Sump Pump w/ Dist, Custom Built Crank Trigger Assembly, and Exchangeable Ratio Blower Drive GearsTop View of Block Shows Porting, Relieving, Dry Decking, Hard Seats   Three Billet Steel Main Bearing Webs Added to 4 Main Bearing Block CHECK OUT THREE ADDITIONAL FABRICATED MAIN WEBS, OVERSIZED CAM BEARING BORES , 4130 CROSSBOLTED CAPS, & HUGE BILLET CAM AND CRANK FOR UNIQUE SEVEN MAIN BEARING BLOWN HUDSON HORNET 9X ABOVE !!   VINTAGE RACE CAR CONSTRUCTION        PAN-AM RACE HUDSON SHOWCASES VINTAGE NASCAR SUSPENSION UPGRADED TO FULL FLOATER 9", NASCAR 4 WHL DISC BRAKES, CUSTOM KONI SHOCKS, 1.250 FRT ANTI-ROLL BAR, 4130 REAR PANHARD, REINFORCED WISHBONES, 32 GALLON FUEL CELL

54coupe

Has anyone seen or heard any of Uncommon's engines? I'm in California, so I'm not local to them. I've seen the website for years, but I've never heard anything either way about them from a neutral party. 

54coupe

49hudsonrod said:

I would like to make 400+ hp out of this engine. To make the money worth it. Is that an achievable goal with this set up, or should I just freshen up an old engine, beef it up, and slap a blower on it and be happy?

I think that 400 HP is pretty ambitious for any flathead six. I don't have any first hand experience with any kind of forced induction, so I can't give any input there. I will say, your biggest hurdle is probably going to be finding the right combination with the cylinder head and head gasket to keep the compression in the cylinders. I'm running 11.25:1 in my drag car, and it has always been an issue. I have an idea, that I am planning on trying at some point, but I'm not ready to do it yet.

49hudsonrod

54coupe said:

49hudsonrod said:

I would like to make 400+ hp out of this engine. To make the money worth it. Is that an achievable goal with this set up, or should I just freshen up an old engine, beef it up, and slap a blower on it and be happy?

I think that 400 HP is pretty ambitious for any flathead six. I don't have any first hand experience with any kind of forced induction, so I can't give any input there. I will say, your biggest hurdle is probably going to be finding the right combination with the cylinder head and head gasket to keep the compression in the cylinders. I'm running 11.25:1 in my drag car, and it has always been an issue. I have an idea, that I am planning on trying at some point, but I'm not ready to do it yet.

What are you thinking? I was thinking going ahead with the 1/2 head bolts and maybe even using studs instead.

Glowplug

This video is what a HET guy did and runs in his hudson coupe  https://m.youtube.com/watch?v=mQmfW7Dz1pc

Glowplug

There is s group of information on the web under the “Hudson Boyz” this group races high horsepower Hudson engines in Hudson and other bodies at Bonneville salt flats 

49hudsonrod

How tuff are the 3 speed overdrives in these cars and what should I do about a clutch.

54coupe

Glowplug said:

This video is what a HET guy did and runs in his hudson coupe  https://m.youtube.com/watch?v=mQmfW7Dz1pc

This is the engine with the billet crank. It is in a 47 Commodore coupe. Butch Smith is the owner.

54coupe

49hudsonrod said:

How tuff are the 3 speed overdrives in these cars and what should I do about a clutch.

The clutches will take some abuse. The transmissions... not so much.

54coupe

49hudsonrod said:

What are you thinking? I was thinking going ahead with the 1/2 head bolts and maybe even using studs instead.

1/2" Head studs are the way to go. You might consider a girdle on top of the head too. I'm planning on making my own cylinder head, and running two plugs per cylinder.

Ol racer

In reality, Hornets have a head gasket problem because of the hold down spacing distance requires 1/2" studs with large NASCAR Lug Nuts, and large grade 8 washers. Adding a blower compounds the sealing problem. The Hudson Boys are a great resource for speed tips. If & when I build another I would consider Turbo....

 The fastest modified drag race Hudson lately was Randy Maas '40 cpe with 5" Stoke, large valves, Isky Cam, Clifford cc head on Alcohol using Triple Weber Carbs and it was durable. Personally, after  Randy's long research modifying Hornets for more HP, I dont think any other combination can match that and be still be durable.

54coupe

Ol racer said:

In reality, Hornets have a head gasket problem because of the hold down spacing distance requires 1/2" studs with large NASCAR Lug Nuts, and large grade 8 washers. Adding a blower compounds the sealing problem. The Hudson Boys are a great resource for speed tips. If & when I build another I would consider Turbo....

 The fastest modified drag race Hudson lately was Randy Maas '40 cpe with 5" Stoke, large valves, Isky Cam, Clifford cc head on Alcohol using Triple Weber Carbs and it was durable. Personally, after  Randy's long research modifying Hornets for more HP, I dont think any other combination can match that and be still be durable.

I agree 100 percent.