The Stovebolt Site Forums The Parking Lot Big Bolts Planning an engine swap in my 46 2-Ton... Ideas?

I'm looking for ideas for an upgrade for my 46 2-ton. I have a modern brake system with disc brakes. I say this because I would like to add a little RPM so that I can do 60-65 MPH. I can comfortably go 50-55 right now unloaded and flat ground. I am smoking a good amount and would just rebuild, but I have the original non pressurized rods in my 235. I know that the later 235-261 engines would be an option, just looking for some other ideas. My criteria would be

-gas engine
-not a modern V8. Or even an old V8 as it seems to common and easy
-looks somewhat original
-Staying with a 6 cylinder? Or at least 6 cylinders on each side...

I have been thinking about a V12 Seagrave engine from the time period. I could see someone needing to do an engine upgrade in the early 50's and using one of these engines from a retired firetruck.

Thoughts?

I am hoping to keep driving the truck this summer and pull it apart this winter to either rebuild or replace. I work this truck in my business and will continue to do so. It is not restored and probably won't be. It is a solid cool old truck that is used to haul stuff from time to time. My heaviest load was a couple months ago. 6000 lbs. of scrap metal. It was struggling a little, but still did the job!

Chevy 292 with NV4500 trans, your truck is screaming for it.

Combo has power and overdrive to get higher speeds. Now that your truck has great stopping power. Meets all your needs without having to touch the rearend.

My $.02

I don't mind the trans I have. I feel like if I could turn a few hundred more RPM I would be ok! I will look into the 292 with that trans.

Thanks

GOOD RECOMMENDATION,I WOULD ALSO SEE IF I COULD IMPROVE THE REAREND GEAR RATIO

I really see no reason for rear end swaps, etc. I want an original looking truck and I want to keep my wheels. My trans operates just fine and I'm happy with double clutching it. Even if I went with the same type of power plant the speed it runs would be ok as long as I don't think I'm going to blow it up running it at 55!

The current engine runs great, just smokes a bunch. If I'm going to go to the trouble of fixing it I would like to upgrade it!

I at least will find a 55-63 Chevy 235-261 to get the pressure fed rods. Anybody know if I could swap the crank and rods out of one of those engines into my block?

Keeping it original on the outside would be awesome!

I agree...no need to change rear. And if you are happy with the 4-speed my choice would be a 261.

Stuff an Allison in there.

No thanks on the Allison. Nice transmissions, but to me not worth the hassle of swapping that in on an original truck.....

Not the transmission, the V12: http://www.oldengine.org/members/diesel/duxford/Allison4.jpg

Didn't think about the engine.... That is something I would stuff in a roadster not an old truck. I guess I could leave the hood off of the truck! You would have to with an engine like that.

I'm looking for gas, period correct engine and not a V8.

I did bid again on the V12 Seagrave engine on eBay, but luckily someone outbid me at the last minute... That would be neat, but a lot of work to make it right!

I'm really leaning towards a 261. I would like something a little different, but that would certainly be the easiest and most reliable option. I did drive it about a 100 miles this weekend! Only used 2 quarts of oil in a 100 miles. If there is a good side, people don't follow me that close.

I know that you said not even a V8 of the time period however a nail head Buick say a 401 wouldn't be one you see every day would give you the power and RPM you're' looking for. The nail head has the wow factor they are not real common but not impossible to find,they build good power and were even the factory V8 for the later later taskforce series 2 ton trucks.

It would sound pretty cool!

That Seagrave V-12,(if anything like an American La France),is a MONSTER!! They are about as long as a G.M.C.426,but 2X as WIDE!! You'd have quite the "Dog-House",if you could even have enough room between the seats. 4 distributors. 24 spark plugs. EXPENSIVE tune-up! Gas mileage would be non-existent. We made a "pulling" tractor,using one of these engines,about 20 years ago. Thing ran well,but needed constant maintenance,to keep everything in-tune. Sold the rig for about 1/10th the amount we had in it! Glad we got that much. It was Cool,but it was a BIGGER PAIN!! Be GLAD that you didn't "Win"! I LOVE my 261,but the 292's are probably your best bet. More H.P.,and they'll take a little more R.P.M. I'd try to decrease your R.P.M.,though,by using either an O.D./Auxy. trans. Easier on the engine,PLUS better fuel economy. Nice truck,B.T.W.!!

Hmm... I will take a look at the nail heads Buick's but I'm pretty set on something in-line or more than 8 cylinders. No matter how uncommon a nail head is, it would still look like a standard V8 to most people.

The more I think about this the more I'm thinking a 261 with dual carbs and making a Fenton type header exhaust for it! Probably balance everything and maybe do a little stronger valve spring to gain a little RPM.

I will also do some more research to see if the crank and rods from a 261 will go into my 235 block.

Sent a P.M.

Randy, just my opinion but I think you are on the right track. Go the 261 route with a few performance upgrades.................that is unless .......you might consider say........something in a Detroit Diesel!

Just not interested in a diesel for this. Maybe in a future project, but it doesn't really fit into what I do with the truck. If I did something modern like that it would be a 496 big block. I had one of those in a 2500 suburban a few years back and loved it. Tons of torque.

I will stay with something that is close to time period correct and not a V8 and is gas. Those are my two big stipulations!

Just about leaves me with a 261 or something big from a commercial vehicle line like the Seagrave V12 I was and may still be considering! Just seems interesting enough to make it work. Will see what pops up in the next month or two. I hope to get something soon and bring it into my shop at home to rebuild this summer so that it is ready for the truck this winter!

Still thinking....This truck would be really awesome with a flathead V12 from an old Seagrave firetruck.

I'm not sold on either yet, but will still be open to idea's that involve a gas engine that is not a V8!

find yourself an old straight 8 Buick

Bill

The Seagrave engine was massive.
Much better power to weight ratio with a Cadillac V-12 or V-16. The 12 should fit into the truck. Overhead valve, made 1930 -37, 16 was made until 40.

Or forget gas and put in a classic GM / Detroit 6/71 diesel. 2 stroke, supercharged (and drips a little oil)

How about the GMC "Twin-Six" 702 ci V12...pass anything but the gas station...

Mike B

The twin six would be something to consider. Seems like they are really stupid in price?

Will look into the straight 8 although that would take up a lot of room.

The twin six rebuilt is only $13k..... I'm not ruling it out, but dang that's a lot of dough.

I would imagine $13k would make a 235 or 261 run extremely, extremely well!

I believe the Twin Six is longer than the Straight 8...

$13k could by you an already done truck...lol!

Mike B

A '52 Buick 320 would be interesting. It came from the factory with a 4 barrel carb.

the Buick 320 had dual carbs from before the war, a 47 Roadmaster I had back in the late 60's had 2 2 barrels with progressive linkage and dual exhaust from the factory, strong highway cruiser, lotsa torque, make a great truck engine

Bill

Went to Speedweek on the Salt Flats over the weekend and saw a car running a straight eight Buick. Pretty cool engine and sounded great, but I placed a pretty decent bid on a twin six on eBay that would look, sound and perform a little better I think. And I think I could fit it in a little easier as far as length goes!

Guess I will see what happens. It's only money!

I have a 51 Pontiac two door with the Flathead Straight Eight.
I will not be doing anything with it in the near future.
And would consider letting it go for what I have in it, if you come pick it up.
The same Straight Eight is in our 54 that I drive on nice days and it has really good low end torque.

Post if you would be remotly interested and I will PM you with pictures and details.

Don

I mean no disrespect but am a little perplexed. I would think there would have to be some firewall and floor modification to fit this engine in your truck
http://flickriver.com/photos/jay_el/2662631849/

But trying to fit this http://www.curbsideclassic.com/blog...5-hp-at-2400-rpm-630-ft-lbs-at-1600-rpm/

would be very difficult. I am no body man or expert welder by any means but wouldn't you have to stretch the frame and the hood amoung other things? Other wise the back half of the engine would be in the cab.
Just asking, maybe I am misunderstanding the whole build.

Bill, The V12 is the same length (or about) as the 235 in my truck! It is 6 cylinder's long. Now it is wider, but that I have room for.

As for the in-line 8.... It is two cylinders longer. With a bore of 4" and wall thickness, cooling jackets etc. that probably puts us up around 10-12" longer than the V-12 or the 235.....

I run a fabrication business and have been stuffing things in were they don't belong for many years. I know how much work is involved. I am a body man as well as a welder/fabricator. I'm more concerned with the length over the width.....

Looks like the "Twin-Six" will quickly get outside of what I am willing to pay. I may start looking for a GM 503 six cylinder....Or if the right 235/261 comes along I will snatch it up and focus my efforts onto something else!

I had a 702 V12 for a while, and I'm all for engine swaps... but I would have never even considered the 702 in a 40's or early 50's 1.5 or 2 ton truck. Seeing the engine in person is different than the pictures, they are quite large and very heavy.

Grigg

Grigg, look like I messed it up. Not twin six, but v-12.
I still think it would be a lot of work but hey, whatever floats your boat.

Same thing Billy, the 702 V12 was also called a "twin six"

I will follow your guys advice. Having not seen a V12 in person I can't judge it's size. Luckily I have been out bid on the twin six and I will let it stay that way.

What do you guys think about a GMC 302 or 503 in-line 6 engine? Looks like the 302 will bolt up to my bell housing...Not sure about the 503?

the 302 would work with a little work. the 426/503 would be too big and lots of work. the 261 imo would work with no work.

There's a guy that has a mid-60's 1-ton G.M.C.,on "Youtube",with a "Twin-6 G.M.C. swap. looks like the hood is extended 2' longer than stock,to accomodate the powerplant. A lot of work,for what appears to be ,(in my opinion),a botched-up mess. check it out,and you'll see what I'm sayin'! Hope this helps.