21 stud engine best upgrades?

[Vanspeed]

Hi guys.
My LB in my 1929 coupe is everything I could have imagined but I would like just a little more power, and I mean a little.

Compared to the stock 4 is pulls great at 40-55 mph but anything before that is pretty stock compared to my 4, at least of what I can recall. I did drive the 4 pretty hard though. Anything I can do that will get me a bit more power?

Currently it is a stock ‘36 LB, bubbas crab cap, brand new 97 from Clive. Stock cast iron heads, cam, the works. Don’t really want to go hog wild. Any thoughts or wisdom?

 

[Tinker]

Just a thought and no wisdom.

Well do you mean power or higher highway speeds. A Mitchel OD will split some gears and give you more speed. It's also not destructive if you want to go back to stock.

No substitute for displacement. Mill the heads for more compression. Or find another set of good heads and mill those and see.

 

[Pete]

Your LB is a VERY poor engine to modify for more power. After market heads and manifolds can be found but are scarce and quite a bit more costly than parts for the 49-53 engines. The blocks can not be bored very much and crank bearings are way more expensive than the late ones. A far cheaper route to go, both initially and in the long run, would be to get a 49-53 Merc engine. It will bolt in with all stock parts and will make somewhat over 100 hp in stock form. You can modify it from there with readily available parts. A very mildly modified one will easily make 130 hp. and that is with a stock cam.

 

[Brian]

I have spent years of my life building up various renditions of 21 stud engines for my 35. I have learnt a lot; what works...culminating with an engine that eats 350 Chevs on the dirt track [FORD- Fantastic On Rough Dirt]. 17 second 1/4 mile in fully street legal 35 sedan. The one advantage of the small 221 displacement engines is, on account of their smaller/ lighter rotating/reciprocating internals, they have a propensity to rev. Therefore, build them to take advantage of this feature. This means, lightening things, letting them breathe, raising compression, and balancing the whole works.
Now once you've done that, it'll no doubt be even slower off the line, which seems to be not what you're seeking. In which case, follow Pete and Tinkers advice. More displacement will get you off the line quicker, but a little, hi revving 221 will go faster.
I admire anyone who perseveres with a 21 stud. Good luck

 

[frnkeore]

I think your best and cheapest route, would be to mill the heads.

Have them take, at least .040 off them and you will notice a difference! From what you say you want, I would guess, it would be just right.

Compression, compression, compression, is that these engines, need the most, whether it's 21 or 24 stud.

If you don't already have headers, they will also help.

 

[TerryOH]

35 engine used the 48 Carb. which is slightly larger. The reason Ford went to the he 97 was better economy.

 

[tubman]

I think your best and cheapest route, would be to mill the heads.

Have them take, at least .040 off them and you will notice a difference! From what you say you want, I would guess, it would be just right.

Compression, compression, compression, is that these engines, need the most, whether it's 21 or 24 stud.

If you don't already have headers, they will also help.

If you're going to all the effort to remove the heads and have them milled, why not go a little bit further and determine how much to mill them to obtain optimum quench. Experience has shown that .050" clearance over the piston tops works best for this. Once the heads are off, make a bunch of foil balls a little larger than a BB and stick them on the top of the piston. Temporarily reinstall the heads and turn the engine over a time or two. Then remove the heads, and measure the thickness of the foil balls. This will give you some idea of how much to mill the heads. If the average thickness is around .080", a .030 cut will be best; if it's .100", you'll need to remove .050".

Don't be surprised if it is already close to .050", as the heads may have been milled before. Also, don't be surprised if the banks are different. I had a set of heads that needed .025" off of one, but .040" off the other. I had another set where the front cylinder on one side had over .100" clearance, the second a little less, the third a little less than that, and the back cylinder was .060". I had to find a machinist that had the experience and equipment to "angle mill" the head, taking more off the front than the back. I have found each situation to be unique to each engine.

After the heads have been milled, I fit them to the engine without gaskets and check to see if there are any areas of contact. I then use a die grinder to clean up any areas of interference. A quick smoothing of these areas is all that remains to be done.

I know this sounds like a lot of extra work, but in most cases, the worst part of the job is going to be getting the heads off the engine, especially if they have been on for a long time. If you're going to go through the grief of taking the heads off, you may as well do the best job of head modification (as opposed to just milling them an arbitrary amount) that you can.

I also like the sound of headers and dual exhaust on a flathead.

 

[Avater]

Interesting point on the head clearance differences. Thank you for sharing!

 

[Floyd]

What TUBMAN said! My LB I have in my 32 is surprisingly peppy and free reving, especially compared to my 81A in my 40 pickup. The big difference is I used OldRon's quench dimension of 0.040 " using aluminum foil balls. This was not easy as I had to find one additional head and still had to do the angle milling dance. When done the range of clearances are 0.037 to 0.043". This makes a huge difference. In my opinion this is a must. I also have calm Schneider 248F cam. perfectly smooth idle. single 97 on stock manifold works fine. The dual exhaust Porter mufflers sound good but as we all really know they don't help performance. As Brian said above these are great engines, just don't try to do too much. Check and set the piston to head clearance. This is where you want to spend your time.

 

[Vanspeed]

Thanks for all the input guys. I do not want it to be fast just a little more peppy. I built headers for it and it sounds awesome. Seems from reading your posts that the heads are the first thing to modify to make it breath better. Anybody run those heads from H&H?

 

[Brian]

I run the Eddie Meyer heads; a definite boost in performance, especially compared to the cast iron heads you're currently running.

 

[Rodrelic]

I don’t imagine you want to take it apart, if it ain’t broke....
But if you do, a mild cam sounds better through the tubes, I think the crude iron plumbing muffles it some. The most fun I had building was making up exhaust as I recall. I have a Harmon-Collins cam and aluminum flywheel, cool sound
If I had a hood I think plenty of room for putting it all inside
Pics of yours?

 

[russcc]

When all is said & done, as stated above, it's compression. The road map was laid out, .040 over the pistons & .060 over the valves. A lightweight flywheel in a light car will be a big boost.