1968 C20 possible swap

[lucas6.6]

I have a '68 c20 with a 350/sm465, been thinking about potentially making a dmax swap my summer project, but I really have no idea where to start. One of the questions I have right now is whether or not I can mate a dmax up to the 465? I want to stick with a manual transmission, preferably the cheapest route possible. Otherwise any and all advice would be appreciated, I haven't started the project yet but I'd like to have a solid plan of attack before I begin. I'd also like to keep it very simple, and budget-friendly, if that's possible haha.

 

[JoshH]

Shouldn't be a problem attaching the trans to the Duramax as GM has been using the same bellhousing for a long time. The only challenge would be finding a clutch. It would suck to drive on the highway without an overdrive though.

 

[SmokeShow]

I was going to say the same as Josh, the trans itself will bolt right up. I, however, have no idea about getting the flywheel, pressure plate, clutch, input shaft all correct.

Is yours a mechanical 465 or hydraulic? If mechanical, I'd imagine the linkage would just need adjusted to provide enough movement to engage/disengage the clutch - no magic there otherwise.

If you're lucky and its a hydraulic 465, I assume you'll be golden as long as the hydraulics are healthy and have enough displacement to engage/disengage the clutch.


As Josh said, no OD on the highway would SUCK. So there ain't no way I'd have a non-OD transmission behind a duramax. That's just my opinion though. If you never need to go over 55-60, maybe it could work for you?

 

[lucas6.6]

This truck would never see highway driving, just cruising around town and maybe some county roads with a 55mph speed limit. I don't plan on building it to haull ass, just to have something unique. As far as the trans being mechanical or hydraulic I'm not really sure, is there an easy way to check?

 

[lucas6.6]

If I decided to find a zf6 to swap in would there be a lot of cutting that would have to be done to the floor pan?

 

[SmokeShow]

There'll be a master cylinder on the firewall if it's hydraulic.


I don't know for sure on the trans tunnel clearance with the ZF6 but they're a good bit larger. I imagine it'll depend on how low you are able to set the engine in the frame. Based on the other swaps that have been shown on here, there is a good chance you'll need or want to section the oil pan on the engine so it can sit as low as possible.

 

[rfletes79]

An overdrive is not necessary. I ran my Chevelle for 30k miles without one, just need the right gear and tire combo. 2.56 gear and 30" tall tire, or a combo close to that. This would get you really close to factory cruising speeds on the freeway. With a truck you may have more options on tire size which would help a lot.

Not familiar with the 465 at all but gear vendors make adapters to bolt to anything, so if you want an overdrive that would work. I switched to the gv 10k miles ago and after a few tweaks it seems to be working good. For everyday/highway use it is really good.

I can set you up with a stand alone harness, tuning, and other stuff to get that motor going. Lmk if you have any questions, glad to help.

Rick

 

[lucas6.6]

There'll be a master cylinder on the firewall if it's hydraulic.


I don't know for sure on the trans tunnel clearance with the ZF6 but they're a good bit larger. I imagine it'll depend on how low you are able to set the engine in the frame. Based on the other swaps that have been shown on here, there is a good chance you'll need or want to section the oil pan on the engine so it can sit as low as possible.

If I sectioned the oil pan to get the engine to sit lower, would it affect the movement of the shifter?