LoL, clever. I have the Model A and I have the 5 speed. The adapter to put the 5 speed behind the Flathead is readily available and I think that I am pretty clear in my mind how to deal with the front motor mounts. What I don’t know about is the whole firewall, radiator, water pump, fan clearance situation. I’m doing a resto of a ‘51 F-1 for a customer and it is my first real exposure to flathead V8’s and the more I work with it the more I think about how cool it would be in my ‘28 RPU. I’m going to be doing some kind of engine/transmission swap it’s only a question of what I am going to swap in.
Work from the front to the back. Put the radiator on, the fan and pulleys on the engine, then slide it between the rails and prop it up. Then slide the body on and see what interferes.
Give the guys at Millworks Hot Rods and Supply a call or message: https://www.millworkshotrod.com/collections/solutions-for-your-traditional-av8-hot-rods They make everything you need to flathead swap a model A, though I think most of their kits involve retaining vintage transmissions/torque tube. Definitely would be my first stop if I end up dropping a flattie in my dad's 30 Model A Coupe!
Ref the T5, Its debateable if its worth the effort . I don't say that from no experience of the swap .Ive had experience of a couple of cars with the conversion and even bought a T5 for myself with a view to converting my coupe but having driven a Flathead powered car with a T5 open drive to an early ford rear, the effort didnt seem to be worth it . Of the 5 gears available, the first gear is so low its not of much use , pulling away in second is more comfortable . 5th gear is pointless unless your above the legal speed limit , and even then you will be downshifting to 4th to get any benefit out of the flatty . With 3.54 gears and 700x16 tyres .. forget it .. you may as well have a 3 speed . With 3.78s its nearly bearable but you need a healthy flathead and be sitting around 80mph to make it worth while 4.11s might make the box work well and be a worthy useable conversion. If your converting the A rear end to open drive be careful and use the correct open drive conversion parts as the internal machining of the part that bolts to the axle is critical to retain the pinion bearing in the banjo unit . Ive seen a later cover used which allows te smaller diameter pinion bearing to walk out of the banjo housing trashing the new crown wheel and pinion.. If your fitting a later banjo rear you will either need to extend the A chassis to accomodate the spring behich axle set up or purchase a pair of spring over axle spring hangers to accomodate the A rear spring . The only mod you might need is some clearance to the fire wall for the right side head and the oil filler / breather .. If you retain the A rear axle and Torque tube, fit a 34 /40 3 speed working from the axle forward , the engine finds its own position in the chassis which just requires engine mounts for the chassis and the small ammount of fire wall clearance.. Model A steering box wont let you fit an exhaust , so your looking at an alternative steering box or steering box position .. even at that the left side rearmost header tube can be tight for clearance .. hope that helps a little ..
I fit a flathead, 3spd, torque tube, and V8 banjo in the 29 roadster without cutting the firewall. I really wanted to run a stock hood too. It was not easy. Lots of trial fitting and measuring. Specific water pumps, home made generator brackets, and the world's smallest fan. Good luck and post pictures
First what year model a as the engine bay is a smaller on a 28-29 the way the firewall is. Second what are you doing for a rearend open or closed . I ask this as this would change on what need to be modified. You can use the stock rearend but when running an open transmission you have to address the rearend. The model a rear has the driveshaft running thru the pinion gear. Plus the torque tube supports the rear from twisting up. The stock radius arms with the spring will not support the rear so modifications will be needed. By using the t5 trans or early ford trans you’re going to need a new mount for the brake clutch pedals . These are all easy enough but in your question what need to be modified. So a bit more information is needed. Sounds like a fun project
Sorry to hear that redoxide did not enjoy the conversion. It's all in the numbers..... Pick the proper trans with the right first gear. Use a diff that puts you in a good launch position. While the overdrive will get you humming with today's hi-way traffic. The 'extra' gears keep you right in the 'powerband' I have told myself many times do the homework and study the facts. However I am a miserable student, no kidding. A willing and learned guru exists. Goes by the handle V8COOPMAN He is registered here, but is more readily found on the Fotdbarn,Early V8. Look him up he has a whole thread covering the process. A masterpiece for those who care to run with fun in an early V8
Since putting a flathead in a model A was fist done in mid '30s should be plenty of info around. T5 is another matter.
@Tow Truck Tom yes it’s all in the gearing and all have to play together . In fact my racecar transmission guy won’t build you one without knowing cam and gearset your running . Have you entertained running a T170 it’s a 3+1 and will get you to highway speeds of 90+
I already have the T 5 and drove my friends Model A with the Banger, it seemed to work well. I do not know what diff ratio he was using. It was an S10 diff and I assume had higher gear than 378
If concerned about the late V8 rear axle and the spring being behind the axle. I have read of people tearing the reared down and reverse the axle housings so that the spring perches are in front of the axle. I know that moves the center line of the axle back and not centered in the wheel well. Of course, you could cut the perches off and weld them to the axle housing.
Folk forget the cam when running the T5 . The flathead doesnt have the legs for the gearing of your average used S10 type set up. which appears to be the usual route to the T5 conversion. Granny first is for pulling loads , One of the cars I drove was a blown flathead and it was really quite a disappointment. The folks that built it recomended a 3.54 gear set with the T5 .. Truth is it was terrible . . the same car grenaded its rear end due to the incorrect open drive conversion housing not retaining the smaller diameter pinion bearing .. hence worthy of checking when you convert to open drive with a 28 to 34 rear axle .. An average T5 would be OK with 4.11s but the work involved fitting it in an A V8 isn't really worth it if your just hot ridding around town.. youll just drive it like a 3 speed There are kits available to retain the A pedals and convert to hydraulic .. Kling ? worth a look and a less onerous option than worn out F1 assembly although the F1 does work pretty good if you fit it properly . save yourself a shed load of work, retain the A rear end and Torque tube , and use a 34 to 40s gear box 39 on if you want syncro in 2 and 3 .. but youll pay more for the later boxes . 40s rear brakes are a bolt on , use 3/16 brake pipe and you wont need to rotate the back plates. you will need to either trim the drum and backplate return edge or fit an axle taper shim or 2 to stop the drum rubbing .. or in some cases you need to do all 3 Fit 40s front spindles and save the headache of fiddling with old piston ring spacers to centre the backplates on the smaller diameter mounting on 28 to 34 spindles .. If you can find one , a 32 K member makes things really easy . I used a reproduction 32 K member made to fit the A chassis , 34 pedals ( because thats what was laying around ) and there a bolt in , 37 gearbox , and an old 21 stud motor from a military Bren gun carrier .. also used a longer clutch lever from a 32 to mate to the pedals easier .. In the attached pics I used the 32 k member as mentioned with 34 wishbones and 40 spindles and a dropped axle . It not all bolt in as the 34 bones spindles and dropped axle bite your ass and dropping the steering arms to suit the mash up is a pain in the butt resulting a a weird looking bend on both arms if you want to get anywhere close to clearance and correct geometry . Ignore the nylocks and overly short bolts , most of these pics were during build up and fasteners were temporary hope they help
Red, can you tell him how much more your rear wheels stick out with those 40 brakes on the stock axle? The OP thinks that they make the axle 2” wider on each side.
If you go with a '32 K member here is how I set my brakes up using '32 pedals. Master cylinder fills through the cutout for the battery. Charlie Stephens
They don't make ay difference to axle width . The A back plate has a recess and a different profile drum face accommodating the parking brake mech .. The 40s are a flatter back plate and consequently a revised drum profile for the newer style parking brake mechanism.. the end result is the same width .. Its just different profiles between the older and newer parts .. Hope that helps ..
its not as simple as that . The spring behind axle spring locatio is roughly 7 1/4 inches from the the centreline of the axle, whicle the spring over is on the axle centre line . A 71/4 increase or decrease if you flip the casings wont look correct. Flipping the bells isnt just a case of swapping them over. it will require re setting the axle preloads and re shimming the bells side for side Its easy enough if you take your time but it can get frustrating and its sore of the fingertips you also need to flip the brakes to there correct side .. its a lot of work to flip the bells . Its a look best reserved for modifieds where the axle is on full view Extending the A chassis to accomodate the spring behind rear axle is the most beneficial way to do it. The A rear spring needs a luttle more stretch to fit the spring behind axle perches but with care and a proper spring spreader it will go .. The added bonus is you gain a 4 inch ( approx ) rear drop without stepping the frame , but if your in the process of lengthening , its easy enough to step it as well for a deeper drop .. If you retain the spring over configuration there is obviously no need to lengthen the frame but you might want to step it to gain a drop . If your intention is to fit an A rear spring to say an S10 rear axle then make sure you take into account the eye centres of the A rear spring once its stretched to its correct fitting length .. Its imperative that the A spring is properly stretched to fit . Its not like any other spring and works in tension . Basically its always loaded .. thats important for the correct rear end stability . Henry was a clever man . Stretched rear frame, spring behind..: F1 centre X member and pedal assembly in a 29 special coupe.
Sorry if I hijacked the post, Its just something I have done a few times and never did it the same twice as every method has its advantages and disadvantages . As for the T5 experience , I never fitted mine as the cars I had fitted one to for a buddy and another couple of cars that I had driven fell short of my expectation for the amount of work and cost involved for the kind of distances and use to which I put my coupe .. I pulled my 3 speed and fitted a modified Volvo amazon box to retain the torque tube and fill in that gap between 1st and 2nd that the stock box and the c10 T5 appear to have .. The Volvo is far from perfect . It has good intermediate ratios and suits the flathead in that respect , but the flatty has more torque than the Volvo and you need to be careful with the shifts as its prone to stressing the synchro .. I end to drive it more like the 3 speed and double declutch if giving it some beans .. If I was worried about the rvs or the economy I wouldn't be fitting a flathead . there just a fun motor with a great aesthetic and lots of useful torque and not great gobs of unusable power . If I wanted to go faster I would probably fit a chevy V8.. but as it is for me the stock flathead does what it says on the tin and is a lot of fun so long as everything stays within its casting I run a stock flathead in the coupe and it could outrun the blown flathead with the goofy 3.54 / T5 mash up. Less so with the 3.78s but the T5 was still pointless in that particular car until you got to around 85mph . It was a decent performer if you tooled around in 3rd It would then pick up its skirts but it was way up into the 60mph mark before you needed 4th and 5th just settled it down once you were flat out .. I think 4.11s would have gave it better legs across the range and made 5th useable . It was a bit like driving a modern 6 speed manual like a MINI .. there great in 3rd but the rest of the box is geared for economy and renders the car gutless . I fitted a T5 for a buddy in his T it was a hoot in first. Far to low geared but pulled like a train to 20 mph lol then crunched it way across the synchro's into 2nd by which time you lost any advantage .. a bit like a stock 3 speed if your pushing it .. To be honest I never drove that car far enough or fast enough to get into 5th but it does get there eventually by all accounts . I guess my experience of the T5 is personal and not standard across the board . There are to many variables when fitted in hot rods .
Here is another way to skin the cat regarding spring behind. Tube crossmember, stepped and narrowed/pinched to live between sub rails.
I drilled the flywheel to accept a chev clutch with hydraulic pull MC. Love that...can compress clutch with my hand even with shortened throwout fork. great for old knees plus the clutch disc fits the t5. Had to cut about 1/2 inch off input shaft but i think that is normal.
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