Swapping my 4.3 v6 for a 350 v8

[mnemeth61]

I have a 1986 K10 and doing a frame off restoration. I have replace the 4.3 v6 with a v8 350. Main issue I have discovered is the transfer case and 4 speed maual transmission is shifted back 5 inch due to the engine mount on the v8 block are off set 5 inches from the v6 block. What are people doing to coreect this? If I keep the same then I will need to lenghten the front drive shaft and shorten the rear drive and a major issue will be the holes in the floor board for the shifters will be back 5 inches. Would an easier fix be to move forward frame cross member by the harmonic balancer and engine mounts 5 inches?

 

[bucket]

V6 4x4's were so uncommon in my area, I have no idea if you just need V8 brackets or if you need a V8 crossmember too.

 

[goldpack]

are you doing this with a donor truck right next to the recipient?

or doing it with loose parts/ catalog parts,...or pick /pull parts?

 

[TomR10]

Did the same swap on my 2wd, the v6 had different brackets from the frame to the crossmember and different frame side motor mounts vs the v8.

 

[Scruffy49]

Did the same swap on my 2wd, the v6 had different brackets from the frame to the crossmember and different frame side motor mounts vs the v8.

Prepping an 85 for the same swap. Factory 4.3 getting replaced with a 1979 date coded 350 and factory 1992 serpentine belt system. Have the complete 92 K1500 to pull frame mounts and engine mounts from. Also going to swap the current plastic tanked aluminum SB radiator for the copper/brass SB big block radiator in the gmt400.

The 350 frame brackets get moved forward 1 hole, right? Frame is factory punched for both V6 and V8 options. Leave transmission crossmember/Th400 as installed, match up frame holes for the engine mounts? Swapping to Energy Suspension engine/transmission mounts once the frame mount location is set. Donor engine turned 335 rwhp with a Qjet when it was in a K10 mud drags truck. Overkill for a 2wd lowrider but working with what I have… Thanks

 

[TomR10]

Nothing overkill about doubling the stock horsepower. Frame is predrilled for v6, v8, turbo 350, turbo 400 or 700r4. You'll see where the brackets need to go, don't know if there is a difference in c10 vs k10. I swapped to a dirty dingo transmission crossmember, the stock one probably doesn't need to move but if it does the holes are there.

 

[Rusty Nail]

All that really sounds like fun (to me) and i'm jealous.
Good luck!

 

[Scruffy49]

All that really sounds like fun (to me) and i'm jealous.
Good luck!

Nothing “fun” about turning 2 roached beaters into 1 functional truck… It is so far beyond “fun” that it is hard to describe… Also doing a flathead 6/3 on the floor/4.78s to 350/SM465 (with pto)/8.8 with 3.55s swap in a 40s Dodge truck I’ve had for way too long in project status…
And in the middle of all this doing 3x Danger Ranger (94, 97, 07) 2wd customs for my wife and our “ought as well be daughter” tenant. And hotrodding a “fuel infested” 99 K3500 dually into a carbed K30…
Metal is metal, make it fit…