realistically will my 304 flathead last

I am planning on building a really nastyyyy flathead for my 30 model a pickup. I hope to go with the potvin eliminator cam and a complete fully balanced **** rotating ***embly like the 304 cid setup. I just want to know if I have a good cooling system , I DONT REV the death out of it and, I blueprint everything realistically will it have to thin of cylinder walls and overheat , or are there any ther inherit problems? anyone running this rotating ***embly? any help or are there any complete balanced 296 ci rotating ***emblys??

 

Is this going to be a driver or only for the track?

 

Why wouldnt you want to rev the death out of it when you are going to all that trouble building the bottom end and using the Potvin Eliminator cam. It should handle it, plus its a flathead so you dont have to worry about floating the valves so the piston hits them and causes a bigger problem. Oh, and dont expect it to be a joy to drive on the street.

 

It will be a street car for cruise nights and nice days on the weekends. but will the cylinder walls be fine and will it overheat because they are thin or no?? Im saying Im not going to beat the snot out of it

 

Then why build the **** out of it and make a high-strung, tempermental engine?

Reliable horspower is way better and more fun than crazy tempermental horsepower.

Shawn

 

Check out http://www.royalkustoms.co.uk/jims.html
this is a UK street driven car, drag raced, hillclimbed and not shy of a dirt track or two. 324 cubic inch!

 

I think you will discover that the thin walls and high compression will cause it to run hot.
Don't spend all that money just to build a "heater."

 

A few years back, a local guy had a 51 Merc with an all out 304. Ran OK , [tho not as strong as you might expect] but it would never stop smoking. The cylinder walls were just so thin they flexed a bit and the rings would never seat. After a ton of work , a hone and re-ring, a chunk of money, and a year and a half of embarr***ment, he replaced it with a 276 and was much happier.

 

A Potvin Eliminator cam is in no way a street cam. However it woke up my flathead dragster 45 years ago.

 

anyone know any balanced 296 rotating ***embly combos????

Im not a sissy so Im not afraid of a big cam.

 

nifty : what block is he running.

 

I had an 8BA bored out .125" with new rings and pistons. It was fine until it started making a clicking sound, then I noticed that the oil level was slowly rising (I was use to it going the other way). Then the oil got thinner and turn greenish gray. Cracked cylinder wall! But it did not overheat. Lasted about a month.

 

If you don`t will rev the motor up, why do you want a big cam then?

304ci with Potvin 425, wakes up at 3K rpm and makes power till a little over 5K

A 400Jr will make power from 2K till 5K

So what is the better cam for a street driven car?

Go figure...

 

can you afford one of those french blocks?

or what about those crazy aluminum flathead blocks-
they're made for the big cubic inches.
TP

 

Of course he can, he's not a sissy

 

This seem like a cl***ic case of crossed purpose. Guys who built 304 inch flatheads with big cams and lots of porting were building race motors. That's what it is. Why would you ever build one and then not use it for what it is? If you want a cruiser then build one. Don't go for the 3 3/8 bore. Be happy at 5/16. If you want the long arm go for it. Get a 3/4 cam fro Dema Elgin or somebody and have an engine built for what your doing.

 

I would ***ume Jim is running a French block but could be wrong, he does rate them for strength though. Have a look at the recent builds as well.
You need to work out exactly what you want to use the motor for, Jim built mine for reliable street use but at present is still capable of a mid 15 p*** (should be high 14s when it's on the money)

 

we are running a 304ci flat with a potvin eliminator cam, extremly ported, big main bearing caps and a 4 carb setup.its driven on the street and the strip.the engine made 3000 miles this year without any problems or overheat... but we used a nos german g29t block and sonic tested it to go save with the cylinderwall thikness. i would never bore and stroke an "old" block to 304cui.these damn engines are to expensive to just try and see how it works.(sorry for my bad english)

 

Don't worry about it; it's better than you get from some of the people born here!

 

What bore and stroke do you need to give 304 cu in?

Mart.

 

Excellent advice. Flatheads are neat. I'm putting one in my '29 Model A rpu. However, you have to keep their power potential -- which ain't much -- in perspective. The engine you're proposing is a cl***ic case of diminishing returns. Build a nice reliable flatty for cruising and enjoy it.

Bob

 

In theory, the thinner the 'walls, the more the heat goes up. also in theory, the radiators from Arizona and other desert areas were different from Ford, to make up for, you know, the heat possibilities. Wanna try ceramic coating?

meanwhile, are you venting the crankcase? That could create some real pressure behind the rings, causing some of that sealing problems others talked about, every time the pistons pump up and down?

 

where would I find a french block? any help

 

Yet what you describe is a full race motor built to pound on for as long as it lasts. Full race flatheads in street cruisers are just there to stroke egos and provide bragging rights. You are correct in wondering if it will last. If you drive it like you stole it, no it won't. If you don't treat it like a rented mule then it's just going to waste.
Hey, you did ask for opinions.

 

Seems like if it already has death in it, you would want to rev it out....death in an engine is bad.

 

France.

 

The engine you want will probably be $8-10K easy.
(I think the french blocks complete are already 5 G's)

Another couple thousand and you can get this.
340 cubic inches



http://www.jalopyjournal.com/forum/showthread.php?t=235617



TP

 

Im surprised no one has said what iv herd many times about 304’s ….. piston stability in the bore is the problem.

Doesnt the 304 combo use 3 3/8" bore? …… there’s tons of 3 3/8” flatheads out there. Why do people still think they overheat?

 

Because of cavitation and inabiliy of the engine to dissipate the engine heat.

 

Because of cavitation and inabiliy of the engine to adequately dissipate the engine heat.