'48 3600 engine swap 216 to 250 Cu. In.

[dinosaurdoctor]

Hi guys and gals. I am new to the forum and knee deep in a 48 chevy 5 window deluxe 3/4 ton project truck. I will post pic's as I get them but for now I am replacing the 216 with a 250 out of a 68 chevy half ton. The 216 was literally run to death with a hole in the #1 cylinder. I was lucky and found a running 250 six with a good granny first trans for $350.00.
Now I get to pull the 216 and make the 250 sit and make power. Does anyone have any suggestions about how to get rid of the torque tube running from the back of the trans to the support bearing on the driveshaft as well as any ideas on a factory motor mount setup ? I know I will be visiting the local wrecking yard but I would really like to know what I am looking for. I know I will have to get the crossmember for the engine to bolt up, But the difference in the trans lengths may be an issue so I hope someone has done this already. Your input is appreciated, Many thanks, Wayne

[octanejunkie]

Welcome!

[whitedog76]

Dino-

You have a loaded question(s). I'm not for sure how to get rid of the torque tube, but a hot wrench always does the job.

You'll need to do a rearend swap from an open driveline truck. That means 55 or newer.

To get the 250 to sit in there properly you have 2 option.

(1) Get a crossmember from a 54 or 55 1st series truck and replace yours. Find a bellhousing with angled mounts. You'll have to come up with your own front mounts though.

(2) Cut that crossmember out. fabricate some side mounts for that 250. Get a universal trans crossmember.

[NEWFISHER]

Heres how I did mine:

Torched the torque tube out of the way, install a rubber glove on the diff end or drain it before hand as it will leak all the way up where you cut it
250 engine with engine mounts complete.
TH350 auto and aftermarket CPP $50 crossmember ( was easier and quicker than fabbing one).
Rear diff from a 67-69 ONLY 6 lug 1/2 truck. I used a 3:73 ratio $150 These are 1/2" WMS to WMS and you will have same bolt pattern and not notice the 1/4" difference on either side.
70's nova driveshaft 27 spline with 1310 rear u joint. other GM cars and trucks from the 70's and 80's will work. had it shortened $100

After owning a few, I despise the early granny low boxes and 3 speeds. if you have to have a manual trans, look into a T5 from an S10. I t will bolt to the 250 bell housing you have. I have a 250 with a 700r4 and used Lokar long shifters on both the 700 and the 350 from the floor and they look like a 4 spd. The 235 with a T5 I fabbed a tall shifter from the forward mount s10 style trans.

If you are stuck on the granny box, the crossmember you have may work. The 250 is longer than the 216. If you position the rear of the valve cover 1/2-5/8 off the firewall, you can still run the mechanical fan up front and clear the radiator at the lower edge ( engine tilts 3-5 degrees downward at the rear causing the fan to hit rad at bottom if not carefull). Bolt the trans up, slide the crossmember into position and mark the holes to redrill for bolts. Install the rear diff. You can flip the springs around so the cross pins center the rear better or use an aftermarket perch with 3 position holes. Measure tailshaft to pinion for a driveline and grab some 70-72 truck ebrake cable clips and a 1/4x 3" bolt to mate the ebrake cables together. Thread the bolt into the truck side ebrake cable, slide the clip over the bolt head and weld that side together, clip the 67-69 cables up and adjust as needed using the threaded bolt.

[OrrieG]

newfisher that rearend info is priceless, your write up needs to be a sticky tech, this question gets asked about every three months.

[NEWFISHER]

Originally Posted by OrrieG

newfisher that rearend info is priceless, your write up needs to be a sticky tech, this question gets asked about every three months.

I log in about every 3 months and see a new thread lol! After you do a few of them, like anything else it becomes second nature. That's what is GREAT about this forum! The information exchanged is awesome. I had the same questions when I laid into my first project and continue to flood my tiny peanut with useful information from here, and purging the stuff that doesn't matter anymore. I just wish I could remember to mow the lawn.

[G&R's57GMC]

Originally Posted by NEWFISHER

I log in about every 3 months and see a new thread lol! After you do a few of them, like anything else it becomes second nature. That's what is GREAT about this forum! The information exchanged is awesome. I had the same questions when I laid into my first project and continue to flood my tiny peanut with useful information from here, and purging the stuff that doesn't matter anymore. I just wish I could remember to mow the lawn.

Would it help if I stand at the far side of the lawn with a fresh bag of In & Out Burgers ?

[OrrieG]

Newfisher, I feel your pain. I was looking for my torque wrench last weekend and was amazed at the number and type of tools I forgot I had hidden in the back of the rollaway... but a client asked me this morning about a building I did 15 years ago for them and I instantly described the interior layout in detail. Funny how the synapse are firing as I get older...

[NEWFISHER]

Originally Posted by G&R's57GMC

Would it help if I stand at the far side of the lawn with a fresh bag of In & Out Burgers ?

GLEN!!!!!

I need to email you, or drive 8 hrs round trip to get those burgers!

[dinosaurdoctor]

Thank you all for your ideas. I'll have to have a bit to let them sink in and a bit of time to stare at the project truck and how it all relates. It all sounds doable, I'll get back with more questions once the cranium clears of smoke. Thanks again, Wayne