So, I've been collecting parts to build a 235 for my '46, but the more I think about it the more I think I'll be disappointed. I'm putting the truck together to be something fairly usable, for going to auctions and swap meets mostly (shop-truck). As such I'd like it to be fairly capable in the hauling/towing department. Nothing too crazy, but something comparable to a heavy-1/2 ton pickup from the 70's+. The truck itself is getting a small period-correct flatbed. I've got a '59 truck rear axle with 3.90's and a '59 front axle (for the bendix brakes). I'm planning to stick with the stock '59 drums all around but run a power booster. My previous plan was for a '54 235 (full pressure from a p/g car), mildly built with a 2x2 intake, and a T-5 from an S10 for a reasonably steep first gear and still having an overdrive. I have pretty much all the parts to do it, including the engine and the trans, but re-examining my goals and the hp I can get from a reasonably built 235 I'm coming up short. I know a 235 would move the truck itself capably, but with a thousand pounds of payload or a small trailer I think I’ll be at a loss? So that being said, what is involved in swapping a SBC into a ’41-’46 truck while keeping it stock-appearing? Either a 283 or more likely a mild 350 dressed up to look like a 283. I’ve found bits and pieces in other threads, but most guys seem to go the IFS route and I don’t want to do that. It looks like I can get a ’55-’59 V8 bellhousing which will work with the ’46 crossmember? Then I’ll either need to weld on a mount for my existing clutch/brake setup or more likely change to a firewall mount clutch/brake combo? If I run a T5 still, on a ’55-’59 bellhousing will I need a crossmember at the tailshaft of the transmission or can I get away with just the bellhousing? Also, are there any motormounts for a SBC that will bolt it up to the existing frame mounts? Looks like Ch***is Engineering has some that bolt to the frame, but I’m guessing I’d still have to cut the originals off? I have searched the other threads, but the search engine isn’t too great at differentiating “1946” and “350” so I get a lot of results, and none I’ve found so far are trying to keep a stock-appearing truck with a SBC. Can anyone point me in the right direction?
Look at how the engine was mounted in 55-59 trucks with the V8...they riveted brackets to the back of the front crossmember, and used the same wobbly mounts as the six. Since the bellhousing mounts were pretty substantial, it works fine. I don't think the bellhousing mounts are the same as a 46 truck, though. You could get a 55-72 bellhousing crossmember and splice in the middle of it to your existing crossmember? just an idea. The T5 ruins it for me...but you don't need to worry about that. I had a 57 one ton truck with a "stock appearing" big block swap, original SM420 transmission, and a later 3.73 geared 8 lug rearend. Did ok on the highway, and I could haul a bunch of weight in the truck. Your truck is a smaller version, but if you go with 16" wheels and tall skinny tires, you might find that the 3.90 gears are actually OK without overdrive. I'm ***uming that since you're keeping drum brakes, etc, you probably don't plan on driving 75-80 mph all the time. also I don't think you'd need the power booster for the brakes, they generally stop pretty good with the 11x2 manual drum brakes, when all the parts are in good condition. Sounds like a fun build, I'm sure you'll figure it out.
The V 8 bellhousing will not bolt to the early crossmember. The first series 55 where the first crossmembers that a V8 bellhousing will bolt up to.
If the '55+ bellhousing won't mount to the '46 crossmember anyway I may as well remove the bellhousing crossmember and run later SBC mounts on the sides and a transmission crossmember. Ch***is Engineering sells later SBC motor mounts that fit the '46 frame, and if I keep it to a fairly mild engine supposedly I don't need a crossmember there. I suppose the other question, before I talk myself totally out of the I6, is what honest performance could I expect from a reasonably built 235? Could I run the truck at 65/70 mph with a small trailer or an honest half-ton of payload? I get discouraged when I see sub-125hp numbers on built 235's. Yes, the plan is keeping the stock wheels. Might have the rears widened a bit, but stock 16's with stock hubcaps and blackwall tires. I drove a '66 C20 as a DD about ten years ago and found those brakes (still manual) to be pretty adequate even with a decent load.
The trick to being happy with the 235 would probably be to get the gearing right. The T5 overdrive might be a bit too much for hauling stuff at that speed. 3.55 or 3.70 rear gears, and no overdrive, would probably be the way to go? But 3.90 gears with tall tires might work ok also. I think it might be a matter of not being used to having an engine running that fast all the time..used to be a normal thing, now we seem to think it's the end of the world, having been spoiled by late model cars and trucks with good overdrive transmissions. Another approach is a bigger six cylinder engine, either a 261 Chevy or a 270 GMC. The 270 GMCs are not that hard to find, compared to the 302.
I swapped out a 250-6 for a 283 in a C10 several years ago. The difference in the way the truck drove was night and day different and that was keeping the 3 speed trans and 3.73 gears. My 250 was stock but even so, it would probably be close in power to a mildly hopped up 235. The 283 just had so much more low end torque that it made the truck a much more enjoyable daily driver even unloaded.
I think one of the problems you are going to have is thinking that the original frame is up to the same task as a mid70s 1/2 ton truck. I have a lot of these trucks and unless it is the 3/4 ton version frame the trucks were not very heavy duty as far as cargo carry/towing.
My old '66 C20 had a 292, and I never found it lacking for power (all things considered), but you're right that it was geared pretty funny. Column shift 3-speed with a really low 1st, 1:1 3rd, and a 4.56 rear (all factory). Granted the tires were tall, but that old long-stroke engine was "all in" just shy of 70 mph. The T5 I've got at the moment is supposedly from a 4-cylinder S10 so the OD ratio isn't much (.86 I think) and the first gear is really steep (4.03). You don't haul/tow in OD anyway, and the 4th is a 1:1 in the T5, so it might not be bad with the 235. At least that was my original thought, prior to considering a SBC instead.
Chevy used that 235 in trucks up to 2 ton,babbit pounders and full pressure, the trucks were geared for 50/55 MPH and quite often 2 spd rear ends, but none the less they ran for many years with proper care and will do the job. It sounds like you've got all the right parts to make it work I'm pretty sure it'll work well for what you want to do.
My '59 Chevy PU had the 235 (stock, but fresh) granny 4 speed and 3.90's. My dad broke down outside Sparks, Nevada, I went from the SF Bay Area, to Modesto to pick up a rearend for his Peterbilt-I'd guess 800lbs or so? along with 4 tires (22.5's) on Al wheels...maybe another 400lbs or so? The 235 held at 3K RPM's pulling Donner P*** in 95 degree heat, running about 175 the whole way. After that trip I saw no reason to put a V8 in the truck, as that's what I used it for, a truck. Don't sell a good running 235 short
So, a couple different companies sell adapters t run a SBC-pattern auto trans behind a 216/235 (Langdons and Buffalo Enterprises). Anyone know why you couldn't flip one around and use it to mount a SBC to a factory 216 '46 truck bellhousing? So I could keep my clutch linkage and foot starter?
The flywheel will be in the same location with respect to the engine, so a block-mount starter would work fine. Or I could space a bellhousing-mount starter back towards the engine a bit if need be. The only question is how thick the bellhousing spacer could be and still clear the flywheel. The Langdon spacer is aluminum, so I'd expect it to be pretty thick. It might be better to have a steel spacer made to keep the thickness down some. Even with steel you'd end up spacing the bellhousing off the back of the motor by probably 3/8" minimum, maybe as much as 1/2". I believe I could machine a little off both ends of the stock bellhousing to preserve some of the stock clutch spacing, and with a slightly extended pilot bushing as long as there are enough splines on the transmission input shaft to fully engage the clutch disc it seems like it could work? I'm surprised if I'd be the first person on the HAMB to try such a conversion?
An easy swap would be to use a Hurst style front mount and a V8 bellhousing with the ears for the mid mount. The hard part for an SBC in a pre V8 GM truck is clearing the steering. A traditional solution was Antler (rams horn) manifolds with the hump cut out of the rear and a piece of bent plumbing pipe welded or brazed in its place. It is not going to look stone stock but it will look period, or you can get a set of headers or build some. The headers we used in @raven AD truck we made from a 15 dollar set of swap meet Camaro headers. As for the 235 and hauling, I like the 235 about as much as a fire hose enema, but it will haul a load if you want it too. Many a hay truck was 235 powered and you will never expect your half ton to haul like that. For a more modern example before we went V8 power in the Raven's AD truck he ran a clapped out stock original crusty junk yard 235 for about 7 years (everyday), it hauled about one of everything. Even drove it to SD to haul a '37 ford coupe back and out ran a blizzard (fighting a head wind and never getting into 5th gear) for about 3 hours, a complete with transmission 392 from Kansas and anything else you could imagine. like I said I love a 235 about as much as a fire hose enema, but I will not discount one for a daily hauler. I would throw the V8 in there and never look back if it were mine but the 235 can be a viable option.
Have you considered swapping to a 292 six? Or even easier, the 261 truck six that came before it? The 261 is a close relative to the 235 and a bolt in replacement. The 292 would be a little easier clearance wise but if you are going to the trouble of a swap, don't blame you if you got to a 350.
If I can't swap the whole axle I'll either swap the spindles (supposedly there's enough meat in the '46 axle to machine it for the later kingpins) or just swap the backing plates onto my spindles. I'd like to swap the whole axle though. I ***ume the issue is it's wider at the spring mounts? I've got a reasonably well stocked machine shop. When I'm done gathering parts I'll have to get creative with some of this stuff... As for engines, although the 292 is a great engine if I go to the trouble of fitting a later bellhousing I'm gonna run a SBC. If I stick with the I6 it's gonna be a 235/261. There's a '59 283 for sale fairly near by. It might be kind of fun to stick with the '59 theme since I've already got the brakes/axles...
The 46 has tapered front frame rails and the springs are setup tapered on the axle. The 59 has straight rails and straight mounted springs on its axle. The 59 may be wider as well.
i built a truck to be my daily and to haul stuff around. for a couple years it was my only truck. 292 six, 350, 1/2 ton post rear, and i used the original front axle and spindles and adapted them to disc's.the bed dumps. Over 100,000 miles and still going strong! i have had 2 yards of stone on it. a couple years ago it was even in an Ethan Allen ad.
I have a 37 p/u with a 57 235 with a T-5 behind it and 3.55 gears and it does not need a V8,that six moves that truck just fine.
That's very similar to the look I'm going for, except the flatbed I picked up is rounded, bead-rolled, and smaller. Looks like you had to recess that 292 pretty far back into the firewall? Also, what did you do for your pedal setup?
firewall is stock. i only needed to trim a small [tiny] amount off the bottom. toe board needed a bulge in the center for the automatic. i used the stock brake pedal and made a bracket to mount it and the master in the original position. i also adapted the original e-brake to the ****** so inside it appears original. i did this before you could buy any "kits" for these trucks. it is a 39 gmc but the cab tin is the same as yours.
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