The Stovebolt Site Forums The Shop Area Engine Shop '36 Low Cab engine swap questions

Hello everyone, new member here. I posted my intro in the Welcome section, so won't repeat all that here. I recently purchased a '36 Low Cab and am trying to plan a drive line swap so I can drive it more often, further distances, at at speeds greater than 45-50mph.

I'm in the planning stages, and looking for suggestions, ideas, and input on an engine swap. I already purchased an S-10 T5 and I have a Ford 9" rear, so please keep that in mind.

I have, and will have, many questions but I'd like to start with motor suggestions. I have a SB 350 already, but that seems kind of boring. I'd prefer to go to a later model straight six, and am considering a 292 or a 250, but open to others. I'd rather stay away from poured babbitt motors unless they've already been converted to precision bearings. I'm not necessarily interested in getting every bit of power that I can (although I'm not opposed to it!) I just want to be able to do a sustained 65mph without pushing the engine to it's max.

My first questions are, is a 292 or a 250 a relatively easy swap in regards to engine length? I understand from my research here that some 292's have longer water pumps. Are the 250's the same? Are there any tricks, or water pump/fan changes to deal with this, or certain engines to look for?

The other issue is motor mounts. I see the 292 has staggered mounts, but not sure about the 250? My stock 207 appears to not have mounts on the side of the block, but rather crossmembers at the front and rear of the engine. I assume any engine swap would require another crossmember, or some sort of fabricated mounts that go directly to the frame. Any suggestions or input on motor mount products or ideas for this situation would be greatly appreciated.

I suppose that's enough for now as there are already many questions there. Trying to keep it on one general topic of good possible engine swap candidates.

Thanks so much in advance for your help!

My '37 is a hybrid of parts, 250 engine, T350 automatic, GM 10 bolt rear, aftermarket radiator, and home made firewall. The 250 is longer, so moving the radiator forward is a must, you also have to lower it or the mechanical fan will hang below the core about 1/2 way. 216/235 must have a much higher water pump. The 292 would help as far water pump hight, but you still have the length, probably even longer due to the balancer with extra pulley grooves.

I replaced the stock firewall on mine due to someone before me with a torch and drill. I recessed the center for the 250 to gain some room, but in-turn got rid of much needed leg room ( wish I had it back ).

Motor mounts and crossmembers were easy, remove the stock trans mount, add new one under engine, and add second new one for transmission. Fabricate mounting plates for rubber mounts.

Radiator support ( dog house ) had to be modified to move radiator, and the mounts on the aluminum radiator had to be removed and relocated also. My lower radiator hose is a combination of steel pipe and hoses. It runs under the oil filter, then loops back over the top and turns into the water pump. I gained about a gallon of coolant just in the hose, there was just no other way to get where it needed to go. Electric cooling fan may solve some fitment issues, but I don't like to see them or hear them.

You have a bunch of clearance above the engine before hitting the hood, where you don't is the floor board. If you raise the tunnel, you loose the throttle pedal location, now you are crowding the brake and clutch. Mine was missing all the pedals so I used aftermarket pieces. The brake is to the left of the steering column, throttle to the right, I drive two footed, getting off the throttle and on the brake is too hard with just my right foot. Its just one of the other things I wish I had thought out better. I use a Lokar floor shifter.

The 250 runs great, its a good engine and parts are easy to come by, they are not cheap like a SBC, but you can get anything you need. There is plenty of exhaust clearance at the steering box with a single pipe, headers maybe not. I added A/C, so more work in the dog house, custom made brackets, and work under the dash was needed.

Don't think the 250 needs low rpm to safely run the speed limit. I have a 3.08 gear ratio with 28" tall tires, 1:1 final drive in the trans, mine is happiest at 2400 - 2500 rpm. 70 mph is easy and it can run it all day long, it will run faster, I just don't like to go that fast. You won't have enough torque to pull if you lower the rpm unless you are on level ground with a tail wind. Mine does not like strong head winds, the big fenders and flat windshield are not aerodynamic at all, just ask all the bugs it kills! It's still plenty peppy around town with the 3.08, I didn't notice much difference when I swapped out the 3.42 for the 3.08. 3.42 was just a bit much at 65-70 mph. Most of my driving involves a highway, so I give up stop light acceleration for highway easy. I can average 20 - 21 mpg at 65-70 mph, never really checked it just around town.

I also have disk brakes on the stock axle up front, drums in the rear, master cylinder under the cab, no power assist. Pedal is stiff, but I'am used to it and it stops good. You will need an adjustable proportioning valve to dial in the rear brakes. They tend to lock up easy due to the lack of weight over the axle. I used a large parking lot and made numerous high speed stops till I was happy with the way worked. One needs to know how its going to act in an emergency situation!

Think about what whees are going to be needed with mismatched axles, will a spare fit both axles?

My whole drivetrain is from a '70 - '79 Camaro/Firebird, the engine, ignition, transmission, rear axle, wheels, and brakes all came standard on these cars, so any parts store will have or can get any part needed to keep it on the road. The only part not GM is the Ford Master cylinder, its from an early Mustang so it too is easy to get.

Plan ahead at least three steps, tack weld, and study on it before committing to final assembly.

Hello, First off Joe H is the man on this and is always there to lend his expertise. I built my 46 around the stock bellhousing and crossmember, pedals etc , this way I could easily swap 216, 235 or 261, easy bolt in. With an adapter got me to the T-5 to open drive with 66 Chev pickup rear and 6 bolt to keep the artillery wheels. I could go on, bottom line your truck is a beauty. Have fun!

Joe, thank you for taking the time to write that big response. Very helpful.

I have a million questions for you, but will stick to a few.

-From reading your post, it sounds like you're saying I could gain adequate clearance for a 292/250 by moving the radiator forward (and down) without having to modify the firewall? Please correct me if I misunderstood you. I'm 6' tall and I already have to stuff myself into this truck, but oddly enough, that's partly what I like about it. But I don't want to be even more cramped!

-Regarding brakes/wheels/axles...(Should I ask this in a different forum??) I was planning on exactly what you are running, which is disc conversion up front on stock axle, drums in the rear, manual and no power booster. Glad to hear it's working for you. So with that being said, I was hoping to run my stock artillery wheels. For the rear, I assume I could just get new axles with the 6 lug pattern. But up front I'm told my stock wheels won't work with a disc conversion, yet I saw a truck (online, not in person) which claimed to have discs and stock wheels. Those who say it won't work claim the caliper will hit the rivets on the inside of the wheel. My thoughts are possibly spacing them out a bit, but I don't know if that's possible. Or finding smaller calipers and making my own conversion kit, but I'd prefer to make it easy and just purchase an already engineered kit if possible.

If you have any thoughts on that, please share. I know your '37 didn't have those wheels, but thought I'd ask just in case you have any insight on this. I'd really like to somehow get solid answers on this prior to ordering my disc conversion kit so I know what bolt pattern to get. Don't want to get the 6 lug pattern if this can't be done because then I can't use the 5 bolt axles I already have for the rear. If it can't be done, would rather just get 5 lug for the front.

-Regarding the foot pedals, this is a major concern of mine. Since I'm keeping it a manual, left foot braking wouldn't work even if I was willing to drive the truck that way. Are you saying there is no way around this issue? Bell housing clearance to the foot board and also having no space for the pedals to be at least somewhere close to where they are now is what I worry about.

I'd really like to keep the truck an inline 6 and was hoping doing so would solve more problems than it creates versus doing the SB 350, but maybe it won't. The 350 is I think 2" (maybe more) shorter than my stock 207, but might create width problems (exhaust to steering box clearance??) And I REALLY don't want to do a V6.

Thanks again.

Ron

I replied to Joe's post before I saw yours. Interesting you used the stock bell housing, but what I don't know is if I could use mine the way you did since mine is a 207, which I don't believe is in the 216/235 family. This is the one bad thing about the '36. So much changed going into '37 and beyond in terms of parts compatibility.

Pedals are a problem, I had nothing to start with and never seen a truck before this one, so I don't know what stock should look like or how much clearance there really is. Using the bell housing Jim did may solve a lot of issues if it would bolt to your engine.

As far wheels go, that's something I know little about, I do know all the GM wheels changed when disk brakes came out. I used a kit from MASTER POWER BRAKES, which used the big GM rotors and single piston calipers from the A-body and F-body line of cars. The small metric calipers may have more clearance. Mine is a 5 on 4.75 bolt pattern. Artillery wheels would be pretty neat if you can make it work. Maybe cut out the centers and weld them in bigger hoops, now that would be cool.

There is room to get the later engine in if you set it back almost on the firewall then move the radiator forward and down. Mine has a mechanical fan, so moved the radiator quite a bit, if you had an electric pusher fan, you could save yourself about 3" of moving. I didn't fully understand the firewall issues when I made mine, I never would have recessed nearly as much as I did, the stock alcove would have been enough I think, but I was looking at the tall deck 292 at the time and knew I would need more hight.

As far as work goes, it would much easier to go with a full pressure 235, it would save a lot of fabricating.

I would certainly be open to a 235 if that gives me enough power to do what I need to do. Someone else in my introductory post in the Welcome section suggested a 235, and it sounds like he's pretty happy with his and can cruise at decent speeds. I will have to research that motor and see how hard they might be to find.

If I could even get my stock motor into the triple digits in terms of horsepower, I may even consider just keeping it, but don't know if there are any parts to accomplish that, or if the bottom end could handle it.

Lots to think about.

How much does your truck weigh? Is a Lowcab a regular 1/2 ton pickup?

My '50 AD cruises fine all day long at 50-60 with stock 216, 3spd, 4.1 rear end.

The 87 hp seems fine to me.

I have been wrong before but I believe it is a matter of the drive ratio rather than the engine size. I have the original 235 in my 54 3100 but a 1979 Nova rear end with 2.73 gears and I can cruise way above the posted limits. In traffic, I can accelerate with the best of the lead feet. but not so much with the show-offs in their Camaros and Chargers. They seem to say look look at me. I know this turning into a rant for me. We have a main highway that goes through my town called The Bypass, it was a Bypass when it was widened to 2 lanes each way and a center lane. But not so much now, it feels like a drag race track. The posted speed limit it 35 and I have set my cruise at that and have traversed the length without missing a green light and have watched heavy foot drivers hit each one. BTW I also have a T5 trans.

Just for reference, my '37 weighs


Weight with two people: 3580 lb.

LF 943 RF 855 LR 912 RR 869

Empty weight, 3167 lb.

LF 826 RF 764 LR 795 RR 784

Stock axle up front 10 bolt rear, oak wood in bed, NO A/C, no power options, heavy insulated cab, 250 ci with T350 automatic.

Dragstrip times and MPH calculate out to about 115 HP at the rear wheels, 17.99 @ 79 mph. at 3350 lbs.

No sure what it weights. Would estimate 3k lbs, give or take. Max speed on this truck is 45 as-is I can manage to get to 50, but that's pushing it and no way sustainable for any kind of distance. I did get up to 55 momentarily going down hill. I'm concerned that I don't have enough power for taller gearing, other than perhaps on flat stretches or down hill, because when in 3rd gear the truck slows down significantly going up grades. This is hilly/mountain country here. If it can't maintain speed in 3rd gear now, not sure how useful the T5 would be behind the stock motor with stock HP.

But this does get me thinking...perhaps I should just change to an open driveline first, before changing the the engine or transmission to see if taller gears alone would be satisfactory.

So that thought raises this question...how easily would the stock transmission convert to an open drive train?

Also, while we're talking about this, does anyone know what the 3rd gear ratio is in my stock '36 transmission?

In all my years playing with the 206.8 engines, I've never seen any "speed" equipment made for them. By the time all of the hot rodding started (post WWII) the 207 was in it's grave and the newer more modern engines were getting all the attention.

To make it an open drive shaft you might be able to use a 3/4 ton AD truck two piece driveshaft...others will know better than me.

Your 3rd gear will be a 1:1 ratio.

Mike B

Thanks Mike! Thought 3rd should be 1:1, but didn't want to assume that.

Your truck weighs about the same as an AD.

How is your clutch? My truck would only go 30 mph up hill. Turned out the clutch was slipping.

Also, what size tires and wheels do you have? The larger the diameter tires you have, the faster your top speed will be for a given rpm.

My truck also had crappy 15" wheels with low profile tires on it when I got it which also slowed it down considerably.

Proper 16" wheels with 30" diameter tires and a new clutch made 65mph possible.

The clutch was slipping a bit when I got the truck. Engine would stay the same, or increase RPM going up hills while the truck slowed down. The pedal had no free play at all. Truck would only start moving in the last inch or less of pedal travel, so I adjusted it to have some free play. I don't think it was allowing full pressure before. Anyway, now the engine bogs down when the truck slows down, so seems like it's holding well now. Perhaps not.

The wheels are the stock 17" artillery wheels with stock size tires, which according to Coker, are about 29" diameter.