Claim of 25% HP bump true?
 

Just purchased a nice '31 Victoria. My first "running" Model A. Long in FH Ford V8's.
Going through a local Dealer's parts catalogue, I noticed a claim of gaining 25% HP with their milled, high compression head. While I do not question the integrity of this company, or this offering, it seems too damned easy!
Can the increased compression, achieved in such a simple way, really bump the HP to that incredible degree?
Phil

Re: Claim of 25% HP bump true?
 

Re: Claim of 25% HP bump true?
 

Consider that the 1932 Model B four-cylinder engine was basically a beefed-up Model A engine. The main differences - aside from a large journal crankshaft that was later counterbalanced - the Model B engine featured a slightly more aggressive camshaft, a larger CFM carburetor with a wider intake manifold and a 4.6:1 cylinder head. That 4.6:1 ratio is only slightly more aggressive than the Model A's 4.2. This engine was rated at 50 horsepower, meaning 10 more than the Model A. That equates to a 25% increase in horsepower. Sound familiar?
The "high compression" cylinder heads being produced today for Model A's and B's are at least 5.0:1. A couple are 6.0 and some even 7.0+. It's not just the compression ratio that makes the extra horsepower. It is also the design of the head's combustion chambers that creates the right turbulence and spark travel that help improve performance. These heads will definitely increase horsepower AND torque. I should think that the 5.0 head might not supply the extra 25% increase (10 HP), but the 6.0 and above heads will give a closer approximation. If the advertised head is one of the heads I described with at least 6.0:1 CR, the horsepower improvement claim is in the ballpark with a little fudge factor allowed.
Marshall

Re: Claim of 25% HP bump true?
 

Good Evening...Ad a Model B intake and Carburetor and the 5.0 head or higher and you will be right on the edge of 50 HP. Ernie in Arizona

Re: Claim of 25% HP bump true?
 

I run 5.5:1 and 6:1 compression cylinder heads on my Model A's. The stock looking 6:1 cast iron cylinder head currently available is the way to go. I notice more power & torque and much better gas mileage.

Re: Claim of 25% HP bump true?
 

I noticed a significant torque increase with my 6.5:1 Snyder’s cylinder head. I also went with a Vortex dual updraft intake. I’m satisfied with my ‘28’s performance. Everyone commenting in the increase is correct. Even 10hp more is very noticeable.

Re: Claim of 25% HP bump true?
 

The quickest, easiest and cheapest way to more HP on the Model A is to increase compression and add a larger carb. The results will amaze you!

Re: Claim of 25% HP bump true?
 

x2!

Re: Claim of 25% HP bump true?
 

...and that settles that! Check please."

Re: Claim of 25% HP bump true?
 

Jim Brierley, post #7,

Would a Model B carb and a machined out intake be a good choice?

Re: Claim of 25% HP bump true?
 

With all the conversations on increased compression, larger carburetors, and intake manifolds, I would make sure that my lower end could handle all these improvements.

Re: Claim of 25% HP bump true?
 

Good suggestion. I'll start the Imodium right now.
But seriously, how would a person go about testing the integrity of the lower end engine components?
Thank you,
Phil

Re: Claim of 25% HP bump true?
 

Rob Doe,

Yes, its done all the time. If your going to run a B carb you need either a B manifold
or a bored out Model A manifold. The B manifold sets the carb at a different angle but can be corrected with ovaling the holes in the manifold out or using smaller bolts.

Re: Claim of 25% HP bump true?
 

Live and learn. I didn't know that. It might explain why my B carburettor cuts out when braking to a stop. The problem with a RHD car is the lug on the intake manifold for the ignition advance mechanism which is present on an A manifold but missing on a B because they supposedly had automatic advance in the distributor.
I am guessing here but does the change lower the intake or raise it. Details would be very welcome.

Re: Claim of 25% HP bump true?
 

The difference is the carburetor sitting at a different angle side to side not front to back or up and down.
Your carb cutting out might be fuel shoshing, might be float level.

Re: Claim of 25% HP bump true?
 

I would like to install a High Compression head in either 5.5:1 or 6:1 such as Snyders, a "B" cam, a "B" carb, and a bored out "A" intake. If I were to use new poured Babbitt mains and rods would that be sufficient for the improvements I want to do? Which head would be the better choice, the 5.5:1 or 6:1? I have been told any HC head could destroy the center main bearing if you drive it at all aggressively. I would just like to be able to keep up with traffic when needed.
As far as I know this is the original 35K miles engine in the car (1930 Town Sedan) and I would like to keep it in the car. This way I could always return it to stock.

Thanks

Re: Claim of 25% HP bump true?
 

Old wives tale about a 5.5:1 or 6:1 high compression head taking out the bearings. I run a 6:1 Snyders head and get better mileage more power and a cooler running engine.

Re: Claim of 25% HP bump true?
 

Of course it would but a 2-throat downdraft would be better.

Re: Claim of 25% HP bump true?
 

Always a good idea, I have always run Model B engines, and they are strong, bigger bearings and better oiling system, but A engines are very strong and reliable too.

Re: Claim of 25% HP bump true?
 

Higher compression and other things that make more power CAN be harder on bearings, BUT don't if you ease back on the ignition timing a bit, which does 2 things. 1) it prevents detonation and 2) is needed because the fuel will be burning faster so is more apt to knock (detonate) Also, driving down the road takes exactly as much power with or without more power, so most driving will not affect the babbitt or anything else.