So i am rebuilding my 400 and want to do roller rockers when i do this. Roller rockers for the 400 are around 280ish for a set and 351C are around 200 for a set.
I know alot of the parts for interchange yet are the valve lifts the same (which would effect the rocker ratios switching from 400 rockers to 351C rockers) i have this makes sense.
Valve lift / cam lift = rocker ratio
these numbers are made up
400:
.8546 / .494 = 1.73 (1.73 is stock ratio or what ive read)
351c:
.4273 / 247 = 1.73

See how these ratios are the same but the valve lift and cam lift are different. if you switched the two rockers would they yield the same ratio. i believe they would but i am not 100% because a ratio is a ratio no matter what.

hopefully this made sense.

 

AFAIK all 351 351M and 400 valve train parts are the same. where are you finding them listed different? They are the same engine family (335 series) Are you sure you aren't looking at Windsor parts?

 

They both use the same ratio of (1.73) so what you have read was either wrong or misconceived.

 

It's the same stuff. NOT different. You got bad information somehow....

 

These around $180
https://www.summitracing.com/parts/c...HqFRoCrIHw_wcB

These are $280
https://www.summitracing.com/parts/s...view/make/ford

I know these are two different brands so obviously there might be some price range. But i found the scorpions when searching the ford 400 motor and found the comp cam ones when searching 351C.

 

The price difference is because the cheap ones are die-cast aluminum. (JUNK!!!)

The expensive ones are billet machined. (GOOD!!!)