427 tall deck motor swap

[puke171]

I found a good deal on a 427 tall deck out of a 83 c70 feed mixing truck a few months back for my 79 K25. I bought a stock rebuild kit from northern. I also got a cam form comp cams. It had a set of 772 heads on it, and a governed holley carb that has to go. My question is are the heads worth having rebuilt and have bigger valves in, or should I get a set of 781 heads. The truck is my cutting truck for fire wood and is used to pull a stock trailer. Also the front u motor mount bracket is broken does anyone know where to fine one besides a junk yard.


COMP Cams 249-11-235-3

Intake Valve Lift (in.)

0.505

Exhaust Valve Lift (in.)

0.515

RPM Range

1000-5400

Int. Duration @ .050 in. (Deg)

218

Exh. Duration @ .050 in. (Deg)

226

Int. Duration Advertised (Deg)

262

Exh. Duration Advertised (Deg)

270

Engine Make/Size

Chevy Big Block (396-454)

Lifter Type

Hydraulic Flat Tappet

Usage

Street/Performance

 

[bucket]

The front motor mount bracket from the C70 is broken? Don't worry about it, your truck doesn't use that bracket. The 427 will bolt up to stock V8 pickup mounts.

 

[anubisani]

343772.....68-86...oval...OPEN...366T, 427T, 454


336781.....73-85...oval...OPEN...454, 118cc chamber, 256/114cc ports

the 781 heads are supposed to be better, heads we used them for racing.

 

[puke171]

This is just a random picture off to be the internet so you can see what I am talking about. The red line is where it is broken. I will get an actual pictures on friday. But a standard 454 bracket should work?

I know the 781 heads are supposed better but I am on a budget and it is not a hot rod. I am just wondering how 772 heads compare if you take out the small valves and have the standard valves put in. Im not to cheap to buy the better heads if it will help alot. But im not going to spend a few hundred dollars on 10 horsepower for a truck that will be covered in cow crap it's whole life.

 

[68post]

For the rpm range your cam is and staying at 427 ci - I'd use the existing peanut port heads and don't worry about it. Same for the larger valves too, but get a valve job if the heads are off.


$.02

 

[bucket]

This is just a random picture off to be the internet so you can see what I am talking about. The red line is where it is broken. I will get an actual pictures on friday. But a standard 454 bracket should work?

I know the 781 heads are supposed better but I am on a budget and it is not a hot rod. I am just wondering how 772 heads compare if you take out the small valves and have the standard valves put in. Im not to cheap to buy the better heads if it will help alot. But im not going to spend a few hundred dollars on 10 horsepower for a truck that will be covered in cow crap it's whole life.

That bracket is only used to mount the engines in the C50-C70 trucks. Half tons through one tons use the regular mounts that bolt to the sides of the block.

 

[puke171]

Okay, I didn't know that every thing I have ever worked on with a big block chevy in it has been two tons and up in grain trucks. Most of witch had to 427 tall deck in them and one with a 366. This is my first big block in a small truck. I knew the small block are on the side of the block.

I know the deck height, oilpan, intake manifold, distributor, carb, water pump, some of the brackets up front, and the pulleys are all a little bit different. Is there any other major differences between a tall deck and a standard 9.8 deck.

 

[68post]

Okay, I didn't know that every thing I have ever worked on with a big block chevy in it has been two tons and up in grain trucks. Most of witch had to 427 tall deck in them and one with a 366. This is my first big block in a small truck. I knew the small block are on the side of the block.

I know the deck height, oilpan, intake manifold, distributor, carb, water pump, some of the brackets up front, and the pulleys are all a little bit different. Is there any other major differences between a tall deck and a standard 9.8 deck.

Only that the pistons have a taller height from the wrist pin to the crown - and that allows 4 rings to be used instead of the normal 3 rings.

 

[Green79Scottsdale]

Running a tall deck also may prevent you from running standard headers. You may be stuck with running manifolds. Also the throttle geometry and other things may be a little off too. You will find them as you progress through the build.

 

[towjoe]

I have a 1980 k30 wrecker someone put a 366 tall deck in. I have a brand new crate 427 tall deck I keep entertaining idea of putting in my 1988 v3500 wrecker. Just have to buy a intake, stock motor mounts should bolt on the sides of it and not need that front mount.