The Stovebolt Site Forums The Shop Area The HiPo Shop 348 in a Task Force Truck

I have a 1957 Chevy NAPCO pickup. Currently it has a 283 with 3 speed overdrive. I have a 348 block and heads at the engine re-builder, it should be done in about a month. The 348 is going in the pickup. I am considering a t5 or nv3500 trans. I was wondering if anyone else has a 348 in their Task Force truck. And if there are any "tips & tricks" or just plain advice that they might want to share. Thanks,
don

The t5 may be a little weak for that 348, you really need to check with someone that works on those transmissions and see if they are strong enough. I would have doubts about it myself.

The NV3500 has a built in bell housing and uses a Hydraulic clutch.

A T5 trans from a V8 application would more than be sufficient, as long as you don't go overboard building the engine. You'll have to convert the T5 to a forward shift location using an S10 Jeep transmission housing.

bump

Don, have you had any luck finding more info on putting the W motor in your truck? I'd be interested in hearing about that swap, too.

We have a '58 Apache 2 w/s 3100 short bed Fleetside, and also a 348 that I, too, would like to drop in. Our truck has a 2nd-gen Camaro subframe, so my situation is a bit different...



Thanks,

Tim

Tim, with anything custom like that you're not going to find much info that pertains to your specific situation. Your best information will be a lot of measuring, etc., and go from there.

Donsz,

Old W 348 is a heavy engine, you might consider how you're going to beef up that frontend to take it. I installed a 348/3 duces, in a 55 Belair. drove it one week and went back to a small block. I didn't like the way the weight threw the car around.

good luck with that beast.

The engine is at the machine shop now. I'm awaiting parts (mainly pistons and rings, everything else has arrived). I do have concerns about the weight, however, feedback from other sources indicates they have had no problems (limited feedback I admit).

This is a NAPCO truck, so I think the front end should be able to handle the additional weight. Meanwhile I'm fabricating a disk brake set-up for the front. I'm following the lead of an install documented on the NAPCO 4X4 site. To the best of my knowledge, this is the only instance of such a conversion, but it appears a very "doable" fabrication.

As far as the 348, the current 283 is great, but I just want a 348. And I believe at my age I don't need to be rational any more. I'm willing to put up with any inconveniences. This is also an install my research shows as being doable, but not quite bolt-in. If you want to see the truck as is, go to http://www.jalopyjournal.com/forum/showthread.php?t=775781&highlight=1957+napco

By the way, I have not, on overall basis, thanked contributors on this site for all the help I received through the years getting this truck done. This a terrific site with terrific people. I never received anything except expert and patient responses.

Thanks, to everyone, and I will provide updates on the engine install.
don

Your truck looks awesome!

I would ignore all the comments on The HAMB about the wheels and tires, I think it looks awesome!

Is the way that the rad is mounted just to get it closer to the motor? That's going to be killer with the 348 in it.

46gmcpu:
Yes, I moved the radiator back. I believe there is a way to do that using stock mountings, but I couldn't see how to do it with the radiator structures I have. It may have to be adjusted for the 348. Thanks for the feedback, I still like the tires and wheels too.
don

A "w" engine added to that truck would just set it off that much more. Go for it, you got a very nice truck there.

NVG3500 (aka HM-290 / 5LM60) in G.M. applications was rated at 300 lb /ft torque however it was never used in anything over 7200 lbs GVWR.

I was at a show this year and the hot rod next to me had a 409 in it,I couldn't believe that no one knew what it was.Might be age I guess.That will be a great engine for you're truck.I'm starting a rod in the spring and am going to install a 400 big block dodge with a 727 trans.Good luck and enjoy.


Pete

In the hot rodding world very few people know as much as they let on, I'm learning. Whether it be identification of cars, engines, or even tuning on vehicles, I'm continually learning how little fellow hot-rodders know about so much of the hobby. It's not an age thing, I'm 27 and some people I know that are in their 50's and 60's know surprisingly little while claiming to be experts. I think it's a product of only knowing what you have and not paying as much attention to everything else.

Don -

I took a bare casting 348, bolted on a pair of clam shell mounts from a sbc, and tried to set it on the motor mounts: the holes on one side almost lined up (clam shell mount was 1/2" too high over the motor mount), whereas the other clam shell was 1" too high and 1/2" too wide for its motor mount. To me, it suggests the mounting bosses on the side of the engine are wider than on a small block Chevy.

I will research if a clam shell mount was ever made for a W motor and let you know.

Tim

I was at a show with the hood up in my 50 3100. I have a 53 235 w/powerglide engine which has the 2 acorn nut valve cover. A snot-nosed youngster walked up admiring my work, then proceeded to call me out for having a 235 in an AD. So there is still hope after all.
Carl

I believe the 57 GMC came stock with the 348. I have a 57 GMC stock V8 Hydramatic and its serial shows as a 348. If the truck was designed with that engine it should handle it

A GMC would not have had a 348, they ran Pontiac engines for the V8 option. There was, however, a 347 option for '57 (one year only option) in GMC. Chevrolet did not offer anything larger than a 283 in a truck under 1.5 ton until well into the '60s, and the 348/409 was never offered in a truck under 2 ton.

'55 GMC came with a Pontiac 288 V-8 option, '56 GMC was optioned with the Pontiac 316 and correct the '57 GMC was the Pontiac 347.

I put a 348 in my '48 and made the motor and trans mounts myself. If you look at the thread I recently posted ....'48 extended cab with attitude, it might give you some ideas.

I used a 348 in mine because I wanted something different.

Did a 409 in a 58 years ago and only problem I recall was the factory cast iron exhaust manifold had to be re-worked a bit to clear the passenger side frame rail. As far as front end weight goes it may be a factor in cars but remember, the engineers designed the truck front ends to work with a full load in the bed which is many more pounds on the front axle than the difference between a BB and SB. With the BB and the bed loaded then weight could become an issue.

You may be correct for a Canadian built truck, they did weird things up there...lol. The 348 didn't appear in US vehicles until 1958.

Mike B

We still do!

Big blocks weigh less than 6cyl generally. Why would a T5 have trouble with an engine 2 cubes less than a SBC 350? I put a 454 in a 56GMC, no problem. The 348 is a heavy engine but is about 5 lbs lighter than an old 235. The 348 is about the showyest engine in the world. Always wanted one or a 409. Get a universal crossmember and mock it in. Need to find what headers fit between frame and clear steering. Use universal cross member for the tranny. Recommend automatic. A whole lot less trouble/money and plenty fast. Use Lokar nostalgic shifter. The 348, being the first Chevy Big Block, had a funky block design for sure, "W" block, 74 deg deck angle, exhaust port spacing looks like a small block.

That's something most folks tend to forget is just how heavy the 235 really is.

The GMC's used Pontiac V8's in the fifties and I think your V8 is probably a 347 Pontiac in 1957. Throw this in the trash if the valve covers are wavy on the bottom.

Nice truck. One like that (a 56) was just bid up to $44,500 on Ebay. Your fender spears are on backwards as are 8-10 in our gallery, several across the Barrett-Jackson stage and all over the internet. The 1957 Chevrolet Truck fender spear is the most misplaced emblem of all emblems in the universe and beyond! Putting a V8, SB or BB, in a TF has been done thousands of times. Lots of info on the web. If anyone is confused, the original poster has a Chevy and knows the engine he wants to put in his truck is a Chevy 348. You take off the front clip, attach a crossover to motor mounts and a crossover to the tranny and lower all that into place. Then assess the radiator, fan, harmonic balancer, headers, firewall/dizzy, steering clearances and transmission shifter location. Then mark the crossover's for cutting/mounting. Give attention to carb level and pinion angle.

You have sharp eyes Bartamos, I never noticed that about the fender spears. I must have put them on looking at other trucks that had them on backwards. I took a look at some old promo pictures and you are right.

The 348 is totally rebuilt and is a tri-carb version. It is "almost" in the truck. I don't have it quite resting on all the mounts yet as it should, I'm off about 1/4 of an inch. I think it is because I installed and aligned the crossover motor mount with the former 283 engine mounts that had a little "adjustment" built in. So I am off a little. I am in the process of making some slight adjustments to the front mounts. I'm pretty sure if I installed the crossover mount with the 348 first, it would fit first time. By the way, with a little extra muscle I was able to install the engine with only the hood removed. I will keep this thread updated with my progress.
don

Well, glad you checked it out, Now, what the heck is that tube/gauge sticking out of the dash? Am I seeing something or imagining?

That is a tach. I made the housing from exhaust tubing. If I had it to do over, I would have made the housing shorter and cut deeper in the dash (to allow the tach internals fit). The dash only has a hole for wiring drilled in it, so in case I decided to go back to stock it would be an easy fix. At the time I didn't have the courage to cut deeper into the dash. I now think it would look better with a shorter extension.
don

Very good work. It looks good as is.

OK, the engine and trans (3 speed OD) are in and everything underneath is done. Now I am at the sticking point with the left exhaust header clearing the steering as I anticipated. However, it is tighter than I thought it would be. I don't think grinding the header will help. I'm wondering if the Sanderson "tight" headers will work, even if I need to modify them.
don

I am open to changing the steering box on my 1957 Chevy truck in order to gain clearance. I can find plenty of power steering alternatives, but I am reluctant to go that route because of the NAPCO suspension. Any ideas or potential sources would be much appreciated. Thanks,
don

the 348 pontiac motor is a good truck motor,dads 56 gmc had one.better for 3/4 applications.gms truck motor plant burned down in mid 50s.so 348 pontiac,olds of that vintage,buick 401s and in big bolts a occasinal caddie motor was found in gm trucks.all would work better than a 283 if ya gonna pack weight or have lots of hills.just my .02

Will it work with the stock exhaust manifolds or is the steering box still in the way?

Mike B

Stock exhaust manifold doesn't work.I have ground it down and will "attempt" welding in a patch. But that may be iffy, with cast iron. I will try pre-heating, then TIG weld, and slow cool-down. I also bought Sanderson blocker hugger headers to modify if required (raw steel). I'll see how it turns out this weekend.
don