How much does a cast iron 350 block weigh without the crank cam or pistons?
you need a casting number some have thicker walls 2bolt vrs 4bolt mains ect.
In a word, yes. The only difference between 250 and 400 engines is the top end, so you just need to replace the pistons & cylinder head etc. As far as I know the crankshaft is the same. Hi, crank actually has a different part number, probably, (and this is a guess) the balance factor will be different as the pistons wont weigh the same as a 250's. Don't forget top end includes carbs ;-)