Hello, Joined because I found some interesting posts. I recently got my hands on a 66 F100 4x4 that has a worn V8 in it. Problem is I'm not sure if it is a 351M or a 400. I beleive it is a 400 out of a 71 Galaxie. The Engine code is D1AE-6015-A2C looking around I have found that number used on both the M and the 400. Any ideas as to how to tell the difference easily?

 

welcome to FTE mbutley,
I will send your info to NumberDummy and he may have info for you. Is the 66 a factory 4x4 or a conversion? Try to post the VIN later too.

 

Welcome to FTE

As original, your truck would have had either a 240 or 300 I-6 or a 352 V8.

The 4th digit of the VIN is the engine code. 1966: A = 240 I-6 / B = 300 I-6 / Y = 352 V8.

There were no 351M engines installed in cars till 1975; 1977 in trucks.

No 351M engine ever used D1AE-A2C as a block casting number.

I believe you are confusing the 351C engine with a 351M engine. They're not the same bare block.

The 400 was introduced in 1971 in passenger cars = Ford 1971 casting # D1AE-6015-A2C. Casting numbers can't be translated to actual part numbers, but the Ford part number for a 1971 400 bare block is D1AZ-6010-A.

The 400 wasn't installed in trucks till 1977.

Valve cover bolts: 352/360/390 = 5 / 351C/351M/400 = 8.

 

Thanks for the information. I didn't think it was a 351M but wasn't sure. I know the engine was not original to the truck...someone put it in at some point. I just ordered a replacement 400 block..I had already had the heads done.

 

Hi and welcome mbutley.
Go into the forums listings, upper left hand corner then go into the engine forums for more info.
Be sure to visit your state chapter and meet some of the nice folks there with an intro: https://www.ford-trucks.com/forums/forum182/