Projects Model A 4-Banger - What Can I Expect

A couple months ago I bought a '31 Model A Coupe. It's a stock, survivor car that runs and drives. I'm considering various directions to go with the car; one of them being to use the Model A's engine. Seeing various 4-Banger threads here on the HAMB has me somewhat thinking in the 4-Banger direction.

The other possible directions I'm considering are a 59AB flathead V-8 w/top shift transmission, retaining a closed driveline; the other being a 4-cylinder 151 Cu In Chevy with a T5 and probably a 8" Ford rearend.

My question is if I were to pursue using the Model A's engine, what kind of performance and/or comfortable highway speed can I expect out of it? The only person I asked said that Henry felt 45MPH was a comfortable speed for a stock Model A, with a possible gust up to ~60MPH. Considering I'm in 55+MPH traffic as soon as I pull out of my driveway I know that ain't-a-gonna cut it. I'm not looking to set any LSR's, but I certainly don't want to be a rolling roadblock and laughing stock of the area.

So...... lets put a budget of about $2500, maybe up to $3000, toward rebuilding the engine as necessary and doing some performance mods. I would have to pay for machine work, boring engine, valve grinding etc., but I can do a lot of the other work myself. I would expect modifications to include a higher compression head, better intake and carb, a bit more of a cam, exhaust header (I can build that), and other mods not extreme or overly pricy. What kind of HP gain can I expect from the stock 40-ish HP, and what kind of highway speed can I reasonably expect? Something about retaining the 4-Banger has a strong appeal, providing it can provide some "real world" useability.

If I omitted info about the car that you need, please let me know. Thanks, in advance!

Lynn

 

7:1 head, Pertronix,SS header, NEW Bill Stipe Model B cam, SU carburetors, Timing strip for timing light, Model B type front motor mount, Alternator, 84-87 F150 3spd w/OD, original rear axle, dropped front axle, self energizing, self adjusting Bendix brakes. 4 States, 20 years, Stay off of the Interstates. This car is peppy but I dont go over 75

 

my model a's are not too exciting, 50 mph crusing speed. but a friend with a motor he built drove 65 all over on the freeways etc. not too exotic, had a 283 chevy harmonic balancer, incert bearings, touring cam, milled stock head, stock carb and 354 gears. the whole motor was balanced and really ran good. on the other hand, the 59ab i'm working on now has 2 grand worth of machine work, 1800 in parts, and its still a pile of stuff. the v8's make that pretty music, have the look, and double the hp stock, but they are expensive to play with

 

Great project.. Hop up the banger and drive it. And yes steer clear of the interstates.......................
I've done it with Model A, our 37 Harley and such.. And a VW bus (what a POS).
Watch out for the idiots and just drive accordingly. Seat belts............

 

Your only going to want to go so fast in a model A regardless of the engine. I am running a banger with a 7:1 head,downdraft carb, custom ground cam, header and its a hoot to drive. I can hit 70 but it likes 50-55mph and will run it all day.

 

I have been working on a 1944 willys jeep , stock flathead 4 runs good with jeep gearing , low , think it would 50 to 60 with right gearing for highway use .

 

Thanks, everyone for the replies. I'm curious, manyolcars, what would you expect it would cost today to build what you have? I'm also curious what the carbs are off of......MGB or something similar, perhaps?

I'd appreciate hearing more........

Lynn

 

They look like HS6s, found on bigger Triumphs and Austin-Healeys and on some Volvos.

Something to consider in light of practical CR limits is a discreet turbocharger blowing through a pair of HIF44s. Converting them to MG Metro Turbo blow-though spec is relatively simple, and they work well. Build the engine for flow rather than compression and cam accordingly, and there is enough potential there to break the bottom end several times over.

Nice thing about SUs is that you can't overcarburate. If you have a twin HD8 set-up from a Jaguar handy, that'll work too.

 

one thing to consider, yes you can get it to go to 65mph with ease.............

juice brakes. you need to be able to stop.

 

w

Yes, that's in the plans. Actually considering doing a mechanical to hydraulic conversion on the '31's brakes similar to a kit Ansen offered years ago. The conversion seems like it would be pretty simple to duplicate with a few off-the-shelf parts and a bit of machining. I discovered this thread from a while back and have been in conversation with someone who has a car that has the Ansen conversion. https://www.jalopyjournal.com/forum/threads/i-d-juice-brakes-on-rhd-34-ford.984379/

Lynn

 

This engine put out 60 HP at the rear wheels with a single Stromberg 97 (photo shows Weber 32/36). To put things in perspective, you can buy two SBC crate motors for the price of a building a good Model A engine. Go to something like a CRAGAR OHV head and you can buy a third crate motor! However, there is a certain satisfaction in doubling the HP of an 80 year old engine

 

Would I be out of line in asking you to put a dollar amount on the cost of that engine build? I'm not made of money, nor do I spend foolishly, but I'm not destitute either.

Lynn

 

I took a completely rebuilt stock A motor that I found added a B cam, Winfield 6-1 head and a Winfield BB downdraft plus a stock B dist. I also lightened the flywheel to 42 pounds and added a V8 clutch. My roadster will cruise at 55 with ease and do 65 but I have a stock 378 rear. If I change gearing or went with an overdrive it would cruise at 65. I would suggest you try and find someone with a hopped up motor and ask for a ride.

 

I dont know current prices but its easy to look up the cam and head and other parts. I like the SU because its the best carbs ever made. Thats backed up by dyno tests. The timing strip points out how pathetic it is to think its timed with a bolt in a cam gear. The Pertronix just makes sense and requires an alternator. 12V makes sense too. My tail light bulbs are ordinary bulbs, no led or britelites. They are 32 candle running and 50 candle stop. Thats the same candle power as the headlite on my 1946 Harley. I've never had one burn out.You can give or receive a jump start with 12V. Use adjustable lifters set with a degree wheel.

After the high performance engine it would be dumb to use the Model A transmission because the 3spd w/OD shifts so FAST. I can leave another A far behind because I can shift so incredibly quickly that it throws my passenger back in the seat.

 

Wow....That sounds like quite a hot rod. Probably just your superior driving skills!

Please tell me about the 3-spd O/D you're using. Your 1st post said '84-'87 F150, but I'm confused, although that's nothing new. A transmission that new would likely be open driveline and require adapting at both ends, wouldn't it? Later rearend or a banjo open driveshaft conversion? This seems to be going w-a-y beyond simply souping up the 4-banger and going faster.....but considering your driving skills no one could probably ever catch you!

 

I would like to expand a little of trailerparks post. Of course it goes without saying that you are going to use hydraulic brakes but there is another problem. The front fenders on a Model A act like airplane wings. Starting at about 55 the front end becomes light. The steering feels like power steering. The bad news is that a side gust of wind from a canyon that crosses the road or a semi pushing a headwind will cause you to change lanes if you are not careful. This problem is amplified with the large side area of the Model A. I agree 100% with trailer park when he says "I can hit 70 but it likes 50-55mph and will run it all day". If you are running 55 at the end of the day you are going to be tired from fighting the car. I base these comments my stock height '31 RDPU with a fairly stock Model B engine and a 3.54 rear end.

 

Lynn,

Just a couple of comments on my AVATAR. I am running a 181 cubic inch Mercruiser Marine engine. This is basically the larger version of the 153 cubic inch Chevy II passenger car engine. It is currently available from GM as an industrial engine. The nice thing is that it has the same bolt pattern in the back as a SBC and a standard speed shop adapter can be used to mate it to a '39 transmission. The '39 transmission will bolt up to a Model A or B rear end. For a Model A you will need to figure out how to mount the wishbone, transmission and brake and clutch pedals (these are all mounted to the frame on a '32). It is light in the front end as I mentioned in my earlier post so a comfortable speed is still about 55 mph. I am running '46-'48 Ford brakes and would suggest you do the same (instead of the ANSEN conversion). I have attached two photos. The first shows the engine compartment and the fact that there is plenty of room for the fan (maybe too much). The second shows my right front motor mount (left is similar). I was advised to incorporate the original rubber biscuit in the mount due the vibration of a 4 banger.

Charlie Stephens

 

Above, Charlie Stephens explains why a dropped axle gives the car more of a wedge shape with the wind pushing the front end down to counteract the kite effect of the front fenders. Lowering the rear of the car helps get the center of gravity down too. A side view of my A shows that the roof slopes down in front. I ran 46-48 rear brakes for years. Self energizing self adjusting Bendix brakes are much better and I have them on all four wheels.

 

Superior driving skills haha I should have mentioned that I use the Model A shifter shaft from Snyders. http://www.snydersantiqueauto.com/gear-shift-lever

Heres the how to do it https://www.jalopyjournal.com/forum...-original-model-a-engine-w-torquetube.728951/

 

Heres the brakes post 4,5,6
https://www.jalopyjournal.com/forum/threads/bendix-brake-conversion.387348/

More here
https://www.jalopyjournal.com/forum/threads/model-a-lincoln-brakes.965517/

 

Glad you mentioned the Bendix brakes. I was going to but got distracted.

Charlie Stephens

 

I have a Mercruiser for one of my other cars. Charlie will you show the other side of your engine, Please?

 

As you can see it has a 153 head. I just put it on temporarily many years ago. The intake manifold is Clifford and the exhaust manifold it stock 153 Chevy II with a sheet of metal welded over the top. The engine originally had an alternator but I think the generator looks more like it belongs there.

Charlie Stephens

 

Obviously, checking the want ads here and over at the Fordbarn will give you an idea of costs. New, a Weber carb with intake, linkage and air cleaner will run $665. The FS complete distributor is $310 (an FS kit for your stock distributor runs $175). High compression heads range from $295 to $450. Headers are priced all over the place. Finally, you need to determine how deep you want to go into the engine. Inserts or Babbit? Probably the best money spent would be for balancing the moving parts and lightening the flywheel. Oh! then you need a V-8 clutch and on and on and on.

I think that I would make sure the engine is sound first, balance it and then add the speed goodies as you go along.

 

skip the weber and save $665. My SUs were less than $50 at the Pate swap meet and theres nothing to rebuild, just clean them. The SU uses a vacuum operated slide for acceleration. The slide opens the jet for more fuel and you always get what the engine vacuum asks for. Instant response when you open the throttle. I've been using one on my 1946 Harley for 42 years. Its the best design ever for a carburetor.
I made the stainless steel header for less than $200. I forgot to mention cutting down the flywheel and the $90 clutch from the 8N tractor store

 

You may also look into a T-5 for a transmission. They are essentially a 4 speed with 5th being an overdrive. The Chevy S-10 T-5 I used has about 15% overdrive. This makes my mostly stock engine push my car about 50 comfortably. It goes faster but I dont want to kill the old babbit engine. I think my car would drive comfortably at 65 with a hot engine. I figure about $3500 for an insert bearing engine with a high compression head and all the other goodies I would need. Saving my money for that!

 

does your shifter get into the seat?

 

want to go fast get the 2.3 mustang 4 cyl and turbo it 5spd od trans and tang rear gear

 

That would seem like a good plan but I already pulled a 2.5L "Iron Duke" 4-Cylinder, T5 transmission and the rearend from a '88 S-10 that I bought to be a donor. I already had a 8" Ford in the shop too in case the S10 rearend would have been a bit too narrow. That donor vehicle program was, of course, before I started thinking about doing a flathead V8 or hopping up the A's 4-banger. I guess I'll just have to build something else after the A. Man, I really love being retired!

By the likely list of parts and prices posted by denis4X4 and manyolcars, desirable to warm up the A's engine, I am not deterred by the cost. What is listed comes up to ~ $1200-1500 providing my cipherin' is even close to accurate. Even doubling that wouldn't be unacceptable considering the list of things that would not have to be changed and modified on the A to switch to another engine.

I also appreciate your input too, Charlie Stephens and Binger. If I didn't already have what I believe to be a relatively sound stock engine, I would have almost certainly gone the Chevy 2.5L route. A big benefit as I see it to th e 2.5L Chevy and T5 would have been quite a bit of weight savings.

I'm not quite ready to dig into the Model A project just yet, but I appreciate all of the input and experience shared during my thinking and planning time. Thanks, gentlemen!

By no means am I wanting to cut off this thread as being "done" so if anyone has more to add please fire away!

Lynn

 

yeah i get it. the little chevy motor is a good choice. dont get me wrong i think the banger is cool did a couple of them myself way back when. but if your out in bfe just easier to get parts for modern motor