motor swap help

[warlordxx]

I am looking in to putting a olds 455 in my 85 c1500. has anyone did this swap or know of problems I might find? its a 72 455-th400 in to a 85 2wd pickup that right now has a 305-th350 I know I need to make a driveline.
what headers will work with this swap or am I stuck with stock cast iron pipes. allso what is the wt. of the 455 and the th400 close will work just trying to see if I will need to get springs for a 454 truck

[chevyguy]

About 100 LBS heavier. The motor and trans will fit, but your gonna have to make your motor mounts. Exhaust will be hit or miss, But i would think your best bet with headers would be huggers, but no gaurantee there since the 455 never came in a truck

[75K30]

Interesting swap. Not long ago we had a fella that wanted to install a 455 pontiac into a truck.
Kind of a bit of work, but interesting none the less.
Believe it or not, car headers will fit in a pickup truck. Since the truck has more room and the steering box is away from the rear of the x-member, car style exhaust fits. Now there are exceptions, and drag race exhaust that gets routed around the frame will not fit, but I doubt you will be running anything this large.
Chevy guy is 100% correct about the engine mounts, but these are not a real big deal in a GM vehicle.
As far as weight, the olds engine is not all that heavy. Change the intake to an aluminum one, and you will be close. Close enough for government work anyway.
You are already aware of the driveline issues, and really the only other issue will be the electric kickdown. The Th400 uses a switch to kickdown. Thats about it.

[Rago]

I think I can help out here. Olds 455 weighs about 620lbs stock. Right in the middle of what small & big block Chevys (SP?) weigh. I suggest getting some aluminum parts to lower your weight & you will be fine. Something else to note... Ever heard of an Olds 350 diesel in a Chevy truck? They made them from 78-80 & everything from one of those trucks will get you what you need. Motor mounts, springs, tranny, driveline, linkages, etc. will all bolt up. Direct bolt in if you can find one of these donors. As far as headers, it's probably a custom job since big blocks & small blocks use different headers. This is definetaly gonna be a torque monster. What is the head & engine casting #'s? I can probably tell you more. Look on the front of the head fo a letter, probably a G if it's a 72. For the block, there should be an F followed by a number on the back, lower numbers like 0 or 1 have higher nickel.

[warlordxx]

I have 2 sets of heads one is a G that has been ported with large valves and a stock set of F's most likely I will use the G heads and save the F's tell some fool wants to buy them... thanks for the info about the olds350 I think there is one of them at the scrap yard

[Rago]

The F heads probably still flow better than your ported G heads. Since it's probably just going into a truck for towing or as a driver, G heads should be fine, but G heads aren't much better than the smogger J castings. I'd sell the F castings to someone doing a resto & you'll more than likely get enough to buy everything you need for the swap.