Engine swap From 250 6 cylinder To 350 sbc

[Owen Pollock]

Hey guys, so I will be rebuilding a 350 small bloc engine and replacing my current inline 6 motor with it. I am wondering what I will need for the 350, ex. Engine mounts, new rad, new trans (I believe mines a turbo 350) or just anything important that i will need before the swap. Thanks !

 

[Ken B]

So I am getting ready to do the same thing. I have a donor vehicle so I may already have the motor mounts, the Trans is a t350 I am keeping and I need to look at wiring harness and radiator cooling capacity. My radiator has tranny cooling lines. Dont know if the radiator can cool a v8, may have to upgrade....

 

[Ricko1966]

What year is your truck? Does it have AC and power steering? What is the donor vehicle? Does it have AC and power steering.

 

[Ken B]

truck is 81c10. Donor 85 k10
neither have ac (wish I had that option) yes power steering.

 

[Ken B]

You must be registered for see images attach

So here is a newbie question....any advice to how to pull the trans and engine apart. and also advice on re attaching to v8 replacement engine

 

[Ricko1966]

There's a sheet metal cover on the bottom between the trans mission oil pan and the engine oil pan. Remove it there will be 3 bolts holding the torque converter to the flex plate take those out. Undo the bell housing to block perimeter bots and the engine and transmission will seperate. I'd pull the engine and transmission as a unit seperate them on the ground and reinstall them as a unit.Use donor truck mounts. Original wiring will work you just have to move a few wires.

 

[Ken B]

excellent advice I was thinking both in and both out at the same time woulda been better than separately.
Appreciate it Ricko!

 

[Ken B]

Gonna tag a question onto this thread.. Kinda related.. What needs to be done to remove the smog pump from an 85 350 sbc? During the swap should be the ideal time to remove the smog pump.

 

[custodian]

I did the same swap in the 73 C10 when I first bought it from an inline 6 3spd on the column, manual brakes, manual steering to the 283 350 turbo, power brakes, power steering.

You'll need to get the SBC V8 clam shell mounts, move the motor mount to the V8 position, the 350 turbo will bolt in the same place as a manual trans. I found a donor vehicle to get my power steering setup, steering column, AT linkages that I needed and bought a rebuilt booster and master cylinder for the brakes.

I used an HEI distributor and ran the wire from the fuse box. Your other wires will be extra long changing from a 6 cylinder to a V8. I just kept them long.

Now I'm taking the 283/TH350 out and doing an LS swap, the trans is going bad, so doing a complete swap, and will be cutting all the unneeded wires out.

Good luck, it's an easy swap from a 6 to an 8.

 

[Ken B]

So the "motor mount v8 position" would be just moving to the other holes?

You must be registered for see images attach

 

[custodian]

So the "motor mount v8 position" would be just moving to the other holes?

You must be registered for see images attach

Move the mount to the top set of holes. This picture is from my 73. Use V8 mounts, can't remember if the 6 cylinders are the same.

You must be registered for see images attach

 

[custodian]

So the "motor mount v8 position" would be just moving to the other holes?

You must be registered for see images attach

Move the mount to the top set of holes.

 

[Ken B]

thanks...just making sure.

 

[custodian]

thanks...just making sure.

You also might have to loosen the bolts mounting the bracket from the frame to the cross member to get everything lined up.

 

[Ken B]

Ok so 5 months later....still no progress on this, I have never seperated a manual trans from the block.
I have the 6 cyl and auto trans out and on the floor. But I have not had the guts to pull the 350 and manual trans out of the 4 x4 donor because I have not done it before. I just went to a local shop and explained what I wanted and they declined to take it on. Cant even say I am spinning my tires....aint nothing moving

 

[Bextreme04]

Ok so 5 months later....still no progress on this, I have never seperated a manual trans from the block.
I have the 6 cyl and auto trans out and on the floor. But I have not had the guts to pull the 350 and manual trans out of the 4 x4 donor because I have not done it before. I just went to a local shop and explained what I wanted and they declined to take it on. Cant even say I am spinning my tires....aint nothing moving

There's nothing special about it just because its a manual.... Just unbolt the bellhousing and slide the engine off the trans. The flywheel, clutch disc, and pressure plate are bolted to the back of the engine. The input shaft of the transmission just slides straight in. On some setups it might be easier to just unbolt the trans from the bellhousing itself(they are usually only 4 easily accessible bolts) and then unbolt anything connected to the parts you want to remove and pull it right out. It doesn't really get any easier