[bigblockv6]

The Jimmy frame was still based on the 1/2 ton truck frame so the added weight will not be a problem. The problem will be with the front springs, you'll need some from a 1/2 ton GMC KM-1500 series if you can find them or just go with an add a leaf. My 68 KM-2500 tended to sit lower in the front even with a factory installed V6, at one point I installed an add a leaf on each side which makes the truck sit level now. Back in the era of 70-72 GMC light duty trucks the V6 was no longer offered from the factory but dealers were equipped to do such a conversion at a customers request, GMC did advertise these conversions in their "Points" magazine.