Engine Rebuild

[Gerald C.]

I have a 250 hp and I'm building a 300hp with another block and 461x heads. Do most of the internals on my 250 hp motor fit the 300 hp such as crankshaft, cam, pistons, etc. Is the only real difference in the motors is in the heads and carburation?

Just trying to save a couple of $$. The 250hp engine runs fine.

Jerry

[Duke W.]

Re: Engine Rebuild

The short blocks are the same.

'62-'64 250 HP used small port/small valve "283 size" heads, a small port inlet manifold, and 400 CFM WCFB.

'65 250 HP used 461 heads, but retained the small port inlet manifold and WCFB, which is why the power rating didn't change. The small manifold ports restrict flow/power despite the higher flowing 461 heads.

Search the archives regarding 327 connecting rods.

Duke

[Bob J.]

Re: Engine Rebuild

The short blocks are the same.

'62-'64 250 HP used small port/small valve "283 size" heads, a small port inlet manifold, and 400 CFM WCFB.

'65 250 HP used 461 heads, but retained the small port inlet manifold and WCFB, which is why the power rating didn't change. The small manifold ports restrict flow/power despite the higher flowing 461 heads.

Search the archives regarding 327 connecting rods.

Duke

In addition to what Duke said the exhaust diameter changes to the larger 2 1/2 inch in the 300HP engines (except with powerglide). Bob

[Joe R.]

Re: Engine Rebuild

Jerry,

There is no reason not to use the crank, rods and 461X heads . You should take them to a local machine shop and have the crank polished and/or turned. The rods should be checked for cracks and re-sized with new rod bolts. The camshaft and lifters should be discarded. The pistons probably won't work unless they are an overbore and the new block can be bored and the pistons fitted to the block.

Enjoy your new motor,

JR