I think to much some slap me, 3s < 5s Options

[macavely]

Ok so toyota has the 3s block which is a great one we all know this .. but see as its te 3th make of the S block wouldn't the 5S be a better block ? ... why would toyota make the 5 th version of the block weeker then that of the 3rd? .... and while at it why would the internals be weaker ? it just would make any senne for toyota to not move up .. and keep there "toyota is for ever " thing going ... and then why would they put the 5S in so many cars and in the one that they sell the most ? unless it can take abuse like a pro ? then i'm thinkin my eingine has 221,XXX K miles on it and she is still strong ... and doesn't burn oil ? now what i want to try is doing is fine and camary with the SS and boost it the right way and see how much before it will blow up ....

[Kwanza26]

The only reason it was designated "5S" is because the block is physically different from the 3S (taller). True the blocks vary by number, but typically with Toyota, unless the changes are fairly big, as in stroke changes or bore changes, they don't re-number the block codes. Bigger numbers doesn't always mean better... and the 5S bottom-end is by no means any better than the 3S bottom-end... in fact, the 5S is far inferior, IMO. Its not a performance oriented design...

Also, when an engine is stroked, basically the stroke value is increased. What affects the stroke value? rods, or crank. In most cases, the crank is what most affects the stroke value, although stroking an engine requires a bit more technical work than simply throwing in a crank with a larger stroke. The 5S crank can be used to "stroke" a 3S bottom-end... but regardless of the set-up, whether it be stroke with the 5S crank, or a 5SG hybrid, either custom rods or custom pistons are gonna be needed.

All in all, dispite of what the MR2 guys may want to think, the 5SFE bottom-end has a very apparent weakness when it comes to making horsepower. It has fairly short rods for its stroke, so speaking from a performance standpoint, it's not so great. The 3S on the other hand, is a squared design... and you really can't go wrong with a squared performance engine.