Trying to figure out best way of mocking up motor in my frame for my model a coupe. This is my first attempt at building one of these and hoping for some advice and tips. It is a 32 bones pinched for a model a. I have a 1942 flathead and 39 3 speed with 9 inch rear end. Just looking for the best way to do it. Thanks guys
While still in process I used an F-1 cross member with the trans mount & pedals intact, made for a real clean transition with bolt in &/or welded side rail tabs, I chose to construct as a drop out for ease of transmission service & simple enlongated holes to aid in fore/aft positioning of the motor/ trans as a unit. I might ad that dual brake master cylinder adapters are readily available if so desired & F-1 steering box should be a good fit if the pinched rails provide sufficient header/manifold clearance. Looks as if how-ever you might be ahead of the game with that nicely built center section & may need only to fab your own drop out, & motor mounts making for a super slick ch***is. Oh yeah...may need to source the open drive parts for that 39 ****** ! Ron
You already have a brand new ch***is with a 9" rear, don't goof around with a '39 transmission. Use a T-5 with a Cornhusker kit to adapt it to the flathead. Then after you have your body and radiator mounted, bolt the engine and trans together and float it in the space to check clearances. You've gotta have your fan on there too. Wise to have your steering in place also to know how much room you'll have for headers. Probably want to investigate brake and clutch pedals at the same time before you make the mounts and weld anything solid.
I've only done a model A on an A ch***is but I think I would put the body on so the rear wheel is centered in the wheelwell. Then install the drive train where it fits at the firewall
Thanks for the advise .. this definitely gets me in the right direction. I have some pedals on the way. Still trying to find steering as of now but will be next on the list.
Basically the radiator is going to drive the location, firewall can always be cut. I agree with alchemy on the trans, why mess with an early trans if you’re already running a 9” rear.
Long read but hopefully good info for ya. I'm by no means a pro since I'm currently in the frame building process with my first A on 32 rails, but I will share my ideas. My plan after I get to the rolling ch***is you have would be to locate the engine like ya say. From my measurements there should be no need to cut the firewall or move the radiator. I believe one reason the old hot rodders went to the 32 ch***is aside from other upgrades is that it gave more room for a V8. I know with my setup using a 48 Flathead I've got plenty of room. Remember to angle the engine up in the front 2 to 3 degrees and match that to your rear pinion angle with the car at loaded ride height. I am going with 2.5 degrees for the engine and 2 degrees for the rear pinion, load will move it up almost 1 degree, so I gave it .5 to compensate. I feel that should be good at cruising speed under slight load. FYI, my engine mounts are from a 32, but the side mounts on the pumps are going to be sitting roughly 2" above the frame rail. I don't want my engine so low I have a hard time with lower radiator hoses, I've seen some ugly setups. I'd rather build a tunnel then cut a corner and have everything laying on the ground, especially since yours looks low. Again, just my opinion, and others have valid points of their own. I do second the T5 setup, however the standard T5 has terrible gear ratio numbers for a flathead to be happy in its power curve. I'm going to be running a Ford T5Z trans which has a much better 1st gear ratio and a final drive ratio. some will insist on just running a T5 but from chatting with numerous people that have them and run them they are by no means a fan of the drive ratios. To each their own right.
Imam supposing you are referring to the ‘standard go to T5) from an S-10. And I agree with you on the ratio issue. But T-5 came in many ratio sets, depending on original application. An answer for that is to ‘build, or have built’ a custom unit incorporating the gear set you want combined with the S-10 type tail housing. MDS (Modern Driveline Service) offers newly cast S-10 style tail housing that allow for the speedo drive desired and other mods that are useful. Ray
Yup thanks everyone for the advise. Still stuck on using the 3 speed . Ride height is off right now got 39 rear buggy spring that still needs to be installed . I'll post as I go thanks
Start by mounting your choice of radiators, and work backwards. It's a lot easier to recess a firewall than a radiator. You can search Jalopy Journal for information on the several combinations of fans, generators, and water pumps that affect how close you can mount the engine to the radiator.
Why? Just cause you have it, you want the "feel" of the early trans, or because you are trying to maintain traditionalism? If it's because you already have it, be aware you will need to do some big parts swapping in it to use it with open drive. Might not be saving much money. If it's because you want the early "feel", I can relate to that. There is nothing else like driving an early trans. The ginger feel you grip the tall shifter with, being so careful to make sure you hit the gear. If you think you are trying to maintain traditionalism, that boat has sailed with the big 9" rear sticking out the rear of your highboy coupe.
In my case I mounted a 32 firewall, cowl top & dash portions to ensure placing of steering column, engine etc. while still keeping plenty of open area to climb over/under & around the ch***is. The t-5 is a good suggestion depending on availability & the $ budget.
You will be over that 39 trans in about 15 feet of driving. or after you blow it up for the 3rd time. They work fine if you don't lean on them too hard, but they **** to shift, they pop out of gear, (until you custom machine all the thrust washers inside the trans for it) leak no matter what you do, and have all the precision of shifting with a limp spaghetti noodle. If you simple must have a 3 speed, get a Ford 3.03 three speed from the sixties and put a late 70's jeep shifter on top of it. I have that set up in my 39 and it works great. 39 Trans is for a closed drive as well, so at the very least you will need to source all the later parts to convert the 39 trans to open drive. by then you could have put a t5 or later 3 or 4 speed behind it. And dont even think about trying to do a burn out with a 39 trans, it will explode sooner than later.
Trans seems like a great spot to upgrade, much more incon****uous than the differential. I have an OT German car from the 70s and it has a terrible little 4 speed in it. The later 5 speeds were the go to but have become so pricey a dude innovated an adapter for a 6 speed out of a Mazda RX8. Cheaper/better. Just a thought.
Talk about a big boat honkin rear, I used a 42 ford 3/4 ton 11 bolt open drive rear in my 32 ch***is, still qualifies as traditional in the dirt track sense of the word & will accept a winters Q.C. with an additional left side bell swapped for the right.
Install radiator. Install engine and trans with the mechanical fan installed 1.5 inches from the radiator. Get yer driveshaft made and install it. Put the body on. Seat, pedal and steering sorta happen together so you fit and are comfortable. Theres alot of ways to do things but thats what I do.
Their suggestions are what you want to follow. THEN!! remember that when you use a 39 box with an open drive rear axle you have to convert the 39 box from closed drive to open drive effectively making it a 47 pickup box. In fact it would be simpler to use a 46/48 (I may have the years wrong) pickup box with floor shift to start with rather than spending the money to convert the 39 box.
Since your frame is pinched, I would set the body on the frame and see how the contour follows the frame. I channeled the body about an inch to not have a visible gap. Rear end should end up centered in wheelwell.
Steadfast Engineering makes sub rails to fit Model A body to Deuce frame rails. I believe they are an Alliance vendor. http://steadfastmfg.com/products Not inexpensive, but makes a hard job, easy.
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