Non-factory engine capacities

09:46 AM

CI (.30 over) CI Stroke Base CI
347 342 3.40 302
331 327 3.25 302
317 312 3.10 302
306 302 3.00 302

Just to add to the mix.

Ian

Thanks guys. Just a few more questions if I may.

Do the .030 overbore engines require oversize pistons? What is the max recomended overbore for the 302?

Any overbore requires new pistons and rings. As for max overbore, I wouldn't take one over .030

[ July 19, 2002: Message edited by: Gordon Levy ]

In reading many of the threads in this forum I've noted that there are a few accepted capacities created from the 5.0L Windsor that were not offered from the factory, most notably the 306 and the 342.

Can anyone comment on how these capacities are achieved and why these capacities were settled on?

Do they require that the cylinders be bored, or stroked, or both? If a significant cylinder bore is required, is there enough meat remaining to allow for a rebore at a later stage, or are there prefered blocks that should be used that have more meat.

What other common non-factory capacities are based on the 5.0L Windsor and why?

Here are a couple of combos for SB fords. All assume a .030 overbore.

CI Stroke Base CI
347 3.40 302
331 3.25 302
317 3.10 302
302 3.00 302 (306 is a .030 overbore w/ stock crank)

418 4.10 351W
408 4.00 351W
393 3.85 351W
383 3.75 351W
355 3.50 351W

I have built 331 and 347 motors based on 5.0 roller blocks with good success. The rod/stroke ratio will effect rev capacity. Bore sideloading is also a consideration. I have a 347 under construction, forged lower end, girdle, etc. The wrist pin does cross the oil control ring land. I've not found this to be a problem although it's not optimum for long term durability. The neat thing is I'll have a wide HP/TQ curve that I can drive all day. I anticipate 420-440hp / 350 ftlb TQ.

The new Dart 351W based block will go up to 4.185" bore and no need for a girdle. If you start with a 4.125 bore (Chevy 400 size) and 4.00 stroke you could get 427 cubic inches with a slightly more oversquare combo then is normally used for the 427 W engines. It would leave you with two overbores to 4.185 inches (440 CI).

Could still build a relatively mild motor and get 450 - 550 HP.

I suppose my questions may be a little mysterious since I didn't give any background.

The intention is to build a reliable high reving engine with some real world considerations. These are,

1) Components must be placed under as little stress as possible hence a preference to short stroke

2) Giving myself the option to perform a re-bore at a later stage if (when?) a re-build is required.

3) Determining which upgraded components are commonly used, and therefore more afordable, then building the engine within the limitations of these components.

Thanks for the information so far, it has been usefull... although I'm scratching my head a little as to why one would build a 306 given that the increase in capacity is less than 1.5%, and in doing so, making the block a throw-away unit if it ever requires a re-bore???

I understand that the Mexican blocks are superior to the regular blocks in some way. Can someone elaborate? Can these blocks, for example, be bored out further than a regular block?

[ July 23, 2002: Message edited by: Chris L ]

[ July 23, 2002: Message edited by: Chris L ]

Mexican blocks have extra webbing around the mains and are beefier in general. It is rumored that they have a higher nickel content but Ford denies that in their FRPP catalog.