305 to a 400

[Chevy305]

I am about to get a 400 and trans out of a 77 grand prix to put in my c/k 1500. What kind of adjustments will I need to make to the engine bay and chasis?
Its a long bed single cab, will I need to do a custom drive shaft?

[408.Luke]

400 block is the same size as a 305 block chevy small blocks are all the same. if u want performance dont put a 400 in it they have lots of problems block crack easy and rod ratio is bad.

[GasGuzzler]

EDIT. I read the OP wrong. What year truck?

[RedHeartbeat]

i thought the 77 Grand Prix had a 305 or 350? Thought only the the T/A got the 400 in 77? Thats an odd combination for a Chevy truck, Pontiac 400 and turbo 400. The BOP TH400 won't bolt to a chevy engine so if you're going to use the TH400 out of it you'll likely be stuck with using a BOP engine. Thats unless its got a Chevy in the Pontiac.

BOP = Buick, Oldsmobile, Pontiac.

[GasGuzzler]

A '77 could have had a 301 so the 400 might be possible too I guess. I'm sure it's not a Chevy 400 unless it's been swapped before. Also could have had a 403 Olds I guess.

[Chevy305]

Im pretty sure its a 400.
1975-1977 Pontiac Grand Prix Engine - V8, 6.6 L, 400 CID; Our Remanufactured Engines Backed By 100,000 Mile / 7-Year Warranty!
..and I'll be using the transmission that goes with it. What ever it may be.
So I wont need to shorten or lengthen my driveshaft?

Im just putting this in to sell my truck for more money.. or I'll sell the motor by itself if anyone is interested.

Oh and my truck is a 90

[RedHeartbeat]

You don't want a 77 GP engine... it's a 301 ci dog... History of the Pontiac Grand Prix - Part 3, 1973-1990

[Chevy305]

You don't want a 77 GP engine... it's a 301 ci dog... History of the Pontiac Grand Prix - Part 3, 1973-1990

What do you mean its a 301? The 301 was the base engine.. It obviously had the 400 option.

Pontiac Grand Prix - Wikicars

Optional engines included a 160 hp 350 in³ V8 or 180 hp 400 in³ V8; those two engines standard on the LJ and SJ models, respectively.

Damn, 180hp? I thought this thing had 400hp? The guy told me he smoked road runners back in the day with this car..

[408.Luke]

wow ok i just read 77 and assumed ops.

[GasGuzzler]

400 hp in '77 would have to be a Ferrari or at least Italian. Smoked a what with a what? He was talking about the late 70's Volare' with the Road Runner stripe package.....