What Does It Take?

[1972RedNeck]

After looking at the engine compartment on my '72 K20 with a 350 and a SM465 in it, I have decided that it is much to roomy. I have a good 454 in the shed that would fill it nicely.

What needs to be changed to put it in there? I have read that the motor needs to be slid forward to clear the firewall. Is this true? If so, how much? Everything else should be fairly easy and straight forward, right?

[1972RedNeck]

Nobody?

[KB71C10BBSUPER]

I am currently putting in a Big Block for a freinds K20. He had a 305/T350. The Big Block needs clearance for the firewall so you won't have to massage it. I am installing a 700R4 which is 1 7/8" longer than a T350. Simply move the Frt. Crossmember 1 7/8", Redrill the Holes and drop the motor in. Fits Nice.
With your Granny box you may want to with an Auto. If not you could just move the motor forward an inch to give you the clearance, But then you are legthing and shorting drive shafts.
With gas on the rise a 700R4 gives you that cruise RPM if you driving a lot of freeway. I did a hydraulic lock-up on the converter so there are no wires to the trans.
I believe trans-adapt make a conversion coupler to make it a bolt in. to your NP205.
Hope This Helps

[1972RedNeck]

Originally Posted by KB71C10BBSUPER

I am currently putting in a Big Block for a freinds K20. He had a 305/T350. The Big Block needs clearance for the firewall so you won't have to massage it. I am installing a 700R4 which is 1 7/8" longer than a T350. Simply move the Frt. Crossmember 1 7/8", Redrill the Holes and drop the motor in. Fits Nice.
With your Granny box you may want to with an Auto. If not you could just move the motor forward an inch to give you the clearance, But then you are legthing and shorting drive shafts.
With gas on the rise a 700R4 gives you that cruise RPM if you driving a lot of freeway. I did a hydraulic lock-up on the converter so there are no wires to the trans.
I believe trans-adapt make a conversion coupler to make it a bolt in. to your NP205.
Hope This Helps

My K20 is a bit of a beat around truck. The 454 is free and I haven't had the truck over 50 MPH (haven't licensed it/dirt road only) and absolutely HATE auto's with married transfer cases. I may in time run a NV4500 and divorced 205 if I can get my K2500 sold.

The firewall just needs to be "messaged" for the valve covers, correct? Will I hurt anything on the interior of the firewall if I drive back a ways? How far does it need to go?

[mrein3]

I remember a guy on here built a 3/4 ton 4x4 with a big block. He had to massage the firewall so it fit. Others lifted the cab a bit. Others posted the big block fit with neither a massage or a lift. I wish I could remember the board member's name because it would give you a treasure trove of posts to read.

[john]

Originally Posted by mrein3

I remember a guy on here built a 3/4 ton 4x4 with a big block. He had to massage the firewall so it fit. Others lifted the cab a bit. Others posted the big block fit with neither a massage or a lift. I wish I could remember the board member's name because it would give you a treasure trove of posts to read.

Would that be Yukon Jack?

[mrein3]

Originally Posted by john

Would that be Yukon Jack?

That would be the guy I'm thinking of

[1972RedNeck]

I just looked under the hood of my neighbor's K20 with a 454. The engine stands are in the original holes and the fire wall hasn't been beat back any. How is this possible? The truck has no lift (body or otherwise). I will have to try to catch up with him some time.