Motor mounts and frame towers?
 

I have a '75 E-150 that I'm going to swap a 351w Roller motor in, are all '75-91 small block frame towers the same for 302 and 351w? Will the older motor mounts work, or do I need to use '92+ motor mounts?

Bump it up.

Obviously no one here knows or has done this same swap.

My pure speculation is IF those engines were available in the years your E150 frame and body were regularly factory options then most likely your roller motor would basically drop right in. Almost certainly you'll need dedicated motor mounts for that engine in that van body/frame---'75 was about the time we were becoming limited on any chassis being able to accept any engine in or of the same brand; Ford, Chevy, Dodge etc.

We can hope user NumberDummy comes along with his wealth of info regarding whether the 302/351's were installed in the '75 E-Series.

Pure speculation here---by far NOT the authority on this----sorry I can't be of more help. :(

What engine originally came in the van?

It's got a 300 six.

OP -- that 351 is wider and taller and was pretty standard on E-Series beginning with the 1992 Generation...............I'd try to stick with 1992 mounts but be mindful of the fact your 1970s generation has different dimensions off the frame, engine "bell" chassis mounting and these numbers are critical given the tight tolerances in vans generally --- have done many engine R&Rs in vans "cab on" and even when using the Motorcraft / Rotunda engine lift tools, the tolerances, clearances are very tight using the factory stuff.

Recommend you consider "cab off" (like they do it when they build these vehicles initially).

Best to get the tape measure out (measure twice or more, count once), do the math, but I'm almost certain you'll need some fab work under those stock 92ish motor mounts and certainly work aft on the transmission mount and other driveline work (e.g. driveshaft mod) given the fact the 300 six's dimensions are different than that Windsor. Things are pretty tight forward of the engine also so there's little room to play around with. I'd mock the entire arrangement up ahead of time.

It's doable, but again, if you can, go cab off.

I haven't been here for a month, so couldn't answer the OP's questions since it wooda been kinda difficult from a hospital bed. :(

351W introduced in 1975 E100/350 // 302 introduced in 1979 E100/250.

E5UZ-6028-A (replaced D7UZ-6028-A) Right & E4UZ-6029-A (replaced D7UZ-6029-A) Left .. Engine Supports aka towers/stands perches / Obsolete

1975/97 E100/350 351W // 1979/96 E100/250 302
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E8UZ-6038-A (replaced D5UZ-6038-A) Right & E8UZ-6038-B (replaced D5UZ-6038-B) Left .. Engine Mounts (steel/rubber insulators) / Obsolete

1975/97 E100/350 351W // 1979/96 E100/250 302.

Welcome back Good Sir and honestly hope you're feeling or doing much better now. :-X22