Big Block in 4x4

[454_72_4X4]

Originally Posted by 1969 GMC

there is a thread right now in 67-72 about yukon jack's hydro clutch conversion in his '69 with a 454. a tad more in depth than just swapping engines, but pretty straightforward. that's the route i would take (and who knows, I may anyway?)

novak sells this kit:
http://www.novak-adapt.com/catalog/kit_hcr3.htm

its a bit cheaper than you usually have to fork out for factory hydro clutch parts (which probably need replaced after 20 or so years of use anyway), and kinda cool too.

LOL, I was just checking out Yukon's thread earlier today!

I'll be using a internal hydro throwout bearing myself, (just because that's what my NV4500 requires), but even though the Novak kit looks like a quality setup I actually prefer facory parts when/if I can use 'em. Not because i think they're better but because if i happen to break something when I'm away from home I can usually find a replacement at the local parts store.

[breeh]

I haven't posted about my experience for several years so here goes:

When I put my BBC in, I also put a 700R4 in. I moved the motor crossmember about 2" forward. I would never move weight forward in my Camaro but in a 4x4 I don't really see what difference it makes. It won't be carving corners. This moved the motor away from the firewall enough so that no clearancing of the firewall was necessary. It also put the motor in about the same spot that a big block resides in a 2wd truck. So, the fan shroud and all of the bracketry for a 67-72 2wd truck goes right into the same places that it should. I somehow lucked out in that once all of this relocation was done, the transfer case shifter (NP205) came right up through the center of the hole in the hump right where it was supposed to. I had to have a rear driveshaft made for the truck but the front driveshaft required no modification. I had planned on changing the rear driveshaft anyway because I was changing from a Rockwell to a NP205. The entire affair was relatively painless (except lifting that 700R4 and NP205 into place!).

[brinegar]

Thanks for all the input guys.
So if I put a 73&up crossmember will I eliminate the driveshaft issues as well as the clearance problems. ?

[breeh]

Originally Posted by brinegar

Thanks for all the input guys.
So if I put a 73&up crossmember will I eliminate the driveshaft issues as well as the clearance problems. ?

No, you can solve the clearance issues by moving the engine crossmember forward but you will then have to move the trans crossmember foward as well and shorten your front driveshaft. The reason that I didn't have to do this on mine is because the 700R4 is longer and took up the space that was created by sliding the engine crossmember forward. Is that clear as mud now?

[TP from Cntl PA]

The 454 in my '72 K-20 was put in with very few mods...........They modified some SBC mounts, but kept the engine in the same location because the driveshafts/trans mounts weren't moved. The biggest problem they didn't take care of, was the fact they should have ran headers instead of the stock manifolds, because on the passengers side they had to cut a hair out of the frame flange on top. The distributor was just a hair away from the firewall, but no problems other wise.

I can take pictures of the mounts they mod'ed, because I promptly tore that BB out of there when I got it. It sits in a place where it can be more useful and efficient............On top a skid

[JAKES 68GMC]

TP, you had a 4-speed in that truck with the 454 right? What did the PO do about the clutch linkage? Is it modded or stock?

[454_72_4X4]

Originally Posted by JAKES 68GMC

TP, you had a 4-speed in that truck with the 454 right? What did the PO do about the clutch linkage? Is it modded or stock?

Mine is a 4-speed also. Clutch linkage is quite a puzzle!

I've got a few pics if my setup.

[watahyahknow]

i've read a story once of a guy that got tired of making room on the firewall and bending sheetmetal to fill the gaps (think he builded stockcars for a living ) , he started using the bottom part of the steel bucket of a wheelbarrow cut to fit and welded intoo the firewall .... looked like factory stock and gave lots of room .
might just be an idea if nuttin else works

[TP from Cntl PA]

Originally Posted by JAKES 68GMC

TP, you had a 4-speed in that truck with the 454 right? What did the PO do about the clutch linkage? Is it modded or stock?

Yeah, truck is/was a 4spd.........They made a bracket and used a modified z-bar, they remounted the arm that connects to the rod from the clutch pedal ass'y inside the truck on the z-bar, and also narrowed it up. They used the stock rod from the z-bar to the throw out bearing arm, and with the 12" clutch it was weak, and would actually bend some. When I dropped the 6 in, I wanted to keep the 12" clutch, so I made a new rod which cured that problem, but if you did a BB swap with a stick, I'd beef it up in that area.

Nothing extreme if you/or know someone who can weld, and to be honest, it looked like who ever did the one in mine was still learning, but it worked

I know on that setup, a aftermarket distributor would have made room between it and the firewall, compared to that huge GM piece that was on it. Also, a pair of headers would have solved their frame grinding issue on the passengers side. But the way the truck looked, they made the swap years ago when parts weren't available from the aftermarket, so they mod'ed stock stuff to work.

[JAKES 68GMC]

Thanks for the info TP. Appreciate it.