I have one week left to do this. I need a short block for a 400m
to replace my 351m, I plan to use My heads , intake etc. on the 400, since the crankshaft and pistons are the only difference
i decided to use a 400 because i want a power increase, and I'm switching the block anyway(totally worn out), and I just put a brand new distributor, hv oil pump, timing chain set, and I was told this could all be transferred over to the 400 , that the only difference to the two was crankshaft and pistons. My request is , Where can I find a short block for a 400, be specific please
and how much of a power increase will I see over my 351m, oh, and while I have the motor torn down , are there any obvious upgrades that I should make over factory? i.e cam,and if i switch the cam will i have to switch rocker arms?
thanks for any and all info but the main question still is ,...where can i find a short block in a hurry, i live in georgia , thanks.

jcf250custom

 

I live in Oklahoma City and there are junkyards all over with 400Ms laying everywhere. If you want to spend some money I'm sure that autozone or any other major auto parts store has rebuilt short blocks. I personally would go to the junkyard. You will never find a brand new block. If you get one from scrap you can put any parts you want in it. Use the heads off of a original 400M 4bbl motor. I hear these heads flow plenty good enough for a 400+ HP buildup.

 

There's no such thing as an "original" 400 4V motor. 351Ms and 400s never came with 4V carbs from the factory. Gee smoker, I thought "most everyone knows" that.

 

Autokrafters has used M blocks for 300$ that were running when they took them apart.

http://www.autokrafters.com

Matt
1978 F250 4x4 - 351M
Don't crush them, restore them!