Another guy trying to do a swap and needing help

If you are determined to go v8, plan on auxiliary radiator fans, no fan on engine (frees up horses), no room. Redesigning the front completely. Not sure about the older models, but '87 on, the heater is center of firewall behind engine. There is a Mazda pickup here I have seen with a 327 in it. The owner added about 6" between the door and front fender (to the frame and the fenders) for a spacious fit.

Option 2: a v6, built to your heart's content, automatic w/shift kit. Drop it in, mount it, hook stuff up and drive a plain regular looking truck, that will burn a tire shifting.
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'90 B2600 extended cab with 4.3 Chevy v6 automatic, carburated and '85 distributor, no bot
'93 B2600 extended cab with carb and modified distributor no bot.
'83 Yamaha Midnight Maxim, 32,000 miles, I got in '89 with 1742 miles on it
One of two biggest regrets: selling my '77 Smokey and Bandit 6.6 TA TransAm in '81

Stop butchering up the truck.
Go to " target="_blank" target="_blank They have parts instructions and experience. The A frame shaped original mounts do get removed. For a Ford SB you
DO not need to cut the crossmember.