The Stovebolt Site Forums The Parking Lot Big Bolts 2 Ton engine swap

I have a 46 2 ton chevy. I want to put a 427BBC out of a project vette that I have with a NV4500 5 speed.

My question is: has any done this before and can I keep the two speed rear?

I have nearly the same truck (Gringo: the '45 2 Ton), I would not hesitate to put a SBC in it this winter. Stuff a 427BBC?, wow, that will really fill'er up. Good luck.

Your 2 spd DP rear should have a 6.03:1 and 7.99:1 ratios if I am correct. Do the math with your final trans ratio and rolling radius of the tire you have mounted and you can calculate the RPM at speed. The cam and torque range of the 427 engine will determine if you are happy with the final ratio or unhappy with the engine booming at speed. I think it is up to you, what will you do with the truck? Like the man said: "How fast do you want to go? How quickly do you want to get to that speed?" It is unlikely you will light-up the 20" tires with even a 427BBC Vette engine, if you rev-it and drop the clutch. But you will have a heck of a hauler. Where is that next gas station anyway?
Best of luck

-Rick M.

I have a 56 that I have built a 496 stroker big block that will have a 540 Allison behind.
http://inlinethumb49.webshots.com/42864/2621987970096773078S600x600Q85.jpg
I believe that you should have plenty room for the swap the problem area will be steering box location and exhaust clearance which I solved by using a Scout II steering box and changing to cross over steering. http://inlinethumb20.webshots.com/43475/2952923250096773078S600x600Q85.jpg
http://inlinethumb59.webshots.com/44538/2116948240096773078S600x600Q85.jpg
I suspect that Grigg will stop by with some help here too as he has also used the Scout II box in his 48.
Take a good look though both our Webshots pages a picture is worth a thousand words you know.

You can find pictures of the Scout II steering box in the axle swap folder by following the link in my signature.

As for any other advice.. sell the gas engine and buy a diesel...

Grigg

If I did sell the chevy motor and went with a diesel, what combination would work with the stock two speed rear? I want to keep it a manual but, I am sold on the gas engine idea yet. It is available in the garage that is why it was an option.

Very little will work with the slow geared 2 speed rear and todays speeds on the highway, perhaps not even your gas engine. Figure speeds and RPM here http://www.onlineconversion.com/bigger_tires.htm

If you want a diesel that is a relatively easy swap the 4BT Cummins (2/3 of a dodge engine) should work pretty well. I think plenty of power, but won't be a hot rod in a 2 ton truck.
Have a look here http://www.4btswaps.com

To try to overcome the poor rear axle gears a six speed Allison 1000 or 2000 automatic transmission with the about 0.65 OD ratio in high will help. Or if manual is a must an NV4500 and a us gear or gear vendors OD unit. Run the numbers, an axle/gear change may be necessary after all, or just drive slow.

If you desire even more power and speed, even with the gas engine idea, you might want to start looking at brake and perhaps even steering upgrades too.

As for a larger diesel, the 6BT comes to mind but I doubt it's worth all the effort to make it fit. Instead I'd start with the 4BT and make some performance upgrades.

In the end you should do what makes you happy, it's your truck.

Grigg

Here is another thought. That Corvette 427 is a motor that has some cache in the right circles. You might be able to sell it to a Corvette restorer for more than its worth as a motor.

Use that money to buy something like a Chevy small block stroker 383. There is a highway capable 383 powered 6400 I see at local shows around here. He is running a stock rear, a stock transmission, the 383 and an over and under box of some sort.

Keep in mind the faster it goes the harder it is to stop.

I already have a 66 two ton that is on the road all the stock running gear is the same as my 56 it now has a mildly built 350 in front of the SM420 that came from the 56. I blew the rear end up and it now has the center section from my 57 parts truck in it. With the SM420 and 10.00R X 22.5 tires which are taller than stock it will cruse at 55 and can make sort spurts to 60. If you used an NV4500 you would have overdrive that would make 60 a high cruse but bearable that is if you also switched to the larger tires. The tire swap from 8.25 x 20s to 10.00R x 22.5 made all the difference in the world the truck had good tires on it before and drove nice but the bigger radials made improvements I would not have thought possible, both in top speed gearing and drivability. I use the 64 to pull a 12 ton equipment trailer and a 14,000 lds mini excavator the whole rig weighing in at 26,000 and every thing has worked out great. keep in mind that all brakes truck and trailer are keep in tip top shape and the rig has the ability to put you though the windshield in a panic stop. This truck dives great handles and stops very well it is however old and requires attention to detail when it comes to maintenance. Keep it safe and start with all new brake system if you keep it stock it must at least be completely rebuilt.
I do have to agree with Grigg though. If I had it to do all over I would have found a late model Top Kick with a diesel and bigger transmission more GVW and swapped cabs for the classic look in a new truck.

Thanks for all the great info. I think I might take Griggs advise and switch to the dodge deisel. I don't know alot about theoptions for upgrading the steering and the braking on these big trucks. I will be usung the truck to tow a rock crawling jeep, andor just driving it aroud. fast speeds above 65 don't really matter to me. I have other cars if I want to go fast.

Hold on now..
I didn't specifically recommend a dodge diesel, but if that's what you want I suggest you pull a tape measure on one of them and the space in your engine compartment.
An easier fit would be the Cummins 4BT.
For either one I suggest you browse through www.4BTswaps.com to learn about them and swapping a diesel in general.

For some steering and brake upgrade ideas have a look here
http://www.stovebolt.com/techtips/bigbolts/p30swap/

Depending on the weight of your jeep a 4BT probably with some upgrades may pull it just fine, or might not be enough power to keep you happy?

I think you're in a tough spot, you want to tow something substantial with an old and reasonably small (under the hood) truck. Not a lot of room to fit larger engines in there nicely, and you should upgrade the brakes too. Lots of work..

Grigg

To OldSub, I am a bit out of place here because I own a 1 ton but I saw you were all talking about transmissions to start. I was wondering what gear ratios you have in as your top gear and rear that would allow you to drive highways. I am working on a 350 SBC to put in my truck I was trying to see if swapping the SM420 for the NV4500 5 speed might give me a better speed for highways.

To ALL, boy would i love to drop in a diesel, but I might have to keep the Chevy thing goin and go with an older duramax. Sorry you Cummins guys. They sound great tho!!!! although I might have to win the loto to pay for it!

College I'm missing some context, I don't see that I mentioned transmissions in this discussion at all.

Short answer is that my trucks have transmissions with a 1:1 (direct) top gear and I achieve highway speed through rear axle and tire size.

My Suburban has 3.08 rear gears and 235/70-15 tires.
My 1-ton (unfinished) has 3.42 rear gears and 265/75-16 tires.

Decide what engine RPM you want at what cruising speed in high gear, then work backward deciding what tire size, transmission OD ratio (if any), and rear axle gear you need to make it happen.

Grigg

Sorry oldsub, I read the post as if you had the 383, my apologies on the one. But I appreciate the info! P.S. Awesome Suburban!