When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
I would say there are more disadvantages to a 351M than a 351W. The 351M/400M engines have a poor engine oiling system compared to a 351 W. Other than a few aftermarket intakes and a few different pistons available there where never any performance parts made for them. 351M/400M engines use the same bellhousing bolt pattern as a 429/460 engine so you can'nt use all the transmissions and bellhousing's made for small block bolt patterns that the 351W shares. And weigh is a lot more for a 351M/400 than a 351W Now days everyone has jumped on the band wagon making parts for the 351W for $275 you can buy a crank(only $195 more than regrinding the stock one), use stock 351W rods and stock 302 pistons and build a really nice .030 351W that is now 396 cubic inches. WINDSOR IS THE ONE TO DO
I would say there are more disadvantages to a 351M than a 351W.
"The 351M/400M engines have a poor engine oiling system compared to a 351 W"
thats just a myth.
"Other than a few aftermarket intakes and a few different pistons available there where never any performance parts made for them"
this is also untrue, alot of 351C parts fit.
"351M/400M engines use the same bellhousing bolt pattern as a 429/460 engine so you can'nt use all the transmissions and bellhousing's made for small block bolt patterns that the 351W shares"
ummm... so
"And weigh is a lot more for a 351M/400 than a 351W"
how much more?
"Now days everyone has jumped on the band wagon making parts for the 351W"
yep.
"for $275 you can buy a crank(only $195 more than regrinding the stock one), use stock 351W rods and stock 302 pistons and build a really nice .030 351W that is now 396 cubic inches. WINDSOR IS THE ONE TO DO"
umm OK.
Of the advantages you listed, only the head flow is significant in any realistic 351M application.
Keep in mind, the 351M is not an original engine design. It is a destroked adaptation of the 400.
The 351M has a tall deck height because its block was originally designed for the 400, which has 0.5" more stroke. The rod ratio is just a happy coincidence of the 351M's shorter stroke with the 400's connecting rods in the 400's block.
Because of its crankshaft weight (about the same as the 400) and the weight of its much taller pistons, the 351M has less high-rpm power potential than the 351W or 351C.
If I wanted a 351 cubic inch engine, I would choose either the 351W or the 351C, both of which are excellent engines that were originally designed to displace 351 cubic inches. Both of them have tremendous performance potential.
The 351C and 400 are old-school designs. Adapting modern engine management systems to a 351C or 400 is not simple or easy. If you have any ambitions for more modern high performance, especially fuel injection, the 351W is by far a better choice.
If you want to upgrade the performance potential of a 351M, you should convert it to a 400 (different crankshaft and pistons, same rods) and build it up from that base.