strokers

[GreyGoose006]

why is it that the only stroker chevy engines you see are 350 ==> 383
i think it would be cool to put a 400 crank into a 305 or 307.
in the 305 you would get a 332-337 depending on if you overbored.
in the 307 you would get a 355-360 again depending on the bore.

is there some mechanical reason that nobody strokes these motors?
both of them would have enormous low end torque, especially the 305, which would be almost perfectly square with a 400 crank.


there must be a reason that i cant figure out, but i'm tired of looking around online and not finding it, so...
any ideas?

[beef_bourito]

well if the stroke is too long it would come out the bottom of the cylender, also the crank might hit on the outsides of the block.

[curtis73]

There are two main reasons why they don't stroke 305s with stock cranks. 1) the bores on 305s are pathetically small and stroking them would make poor breathing and a very poor bore/stroke ratio. 2) the mains on 305s are smaller than other small blocks, so the cranks won't physically fit.

For a while there were companies making the small-journal stroker cranks for 305s, but they lasted about as long as the popularity of the 305. The aftermarket only supports what we capitalist gluttons are willing to buy and the 383 is just a hot ticket.

The 307 is a little better in the bore department but still pretty small, and why stroke an oddball 307 to 350 cubes when you can pick up a 350 with a better bore for $50? Just not practical. I'm sure its been done, but not commonly

[GreyGoose006]

well i was just thinking that the longer stroke of a 400 crank in a 305 or 307 would make a lot more torque than a stock 350.
plus if you already have a 305 or 307, it wold be kinda fun to have a 305 on the outside and a 355 on the inside.

i realize that the small bore would somewhat limit breathing, but there must be a way around it as there are plenty of cars that have nearly equal bore and stroke.

it was really just a thought, but it would be cool to do.

[GreyGoose006]

Originally Posted by beef_bourito

well if the stroke is too long it would come out the bottom of the cylender, also the crank might hit on the outsides of the block.

i thought that the only real difference between the 305 and 350 was the bore.

[curtis73]

You are right. Since the architecture of all small block chevy blocks is the same (with differences in bore and main bearing sizes) all strokes should naturally fit in all blocks; both with respect to block clearance and cylinder height for pistons to displace.

[beef_bourito]

Originally Posted by GreyGoose006

i thought that the only real difference between the 305 and 350 was the bore.

just throwing a guess out there, i don't really know the geometry of any engines so that was about as useful as i could have been.

[GreyGoose006]

curtiss hit it on the head.
the internal dimensions and pretty much everything else about every small block chevy ever is identical. with the exception of 1955, as they didnt have a cast in oil filter (cool little bit of trivia).
to get the different displacements, gm just pulls a crank from say, this engine, and the bore from, say, this engine. put it together and bam.

it seems to me that if the internals were all meant to be interchangable (except the 400) then they should be interchanged.

not really sure where this is headed.
well, uh.

[curtis73]

I say, do it! A long stroke 355 might be neat. You could turn down the journals on a 400 crank. Maybe even offset grind the rod journals and get a 3.875" stroke That's 366-377 in a 307 block and 340-351 in a 305 block.

Torque monster.

You can help breathing with good heads, but resist the urge to go larger with valves. Any increase in valve size might lose flow since they'll be so close to the bores. Fully port the heads, 30* backcut on the valves, intake matching, some small tube long headers. It'll never scream, but it will make decent power up to 4500-5000. Might move your B-body pretty nicely

[534BC]

To test the theory I have state it backwards. My answer is "no"

If you had a 400 Chevy would you sleeve-down the bore to 305 bore size?

Money and time ould be better spent in scrounging classifieds,enginecoreshops,junkyards for the original 400 or even a 350 and there's no "extra" cost or labor involved in machine work.

[GreyGoose006]

but if you already have the 305/307...
all you pay is:
new/refinished crank (about $250)
pistons (75-200 depending on quality)
rods (again, depends on quality)

and you get an engine that looks stock, will still meet nearly every emissions test with ease, and you know that it will fit back in where it came out.
if you put a 400 in place of a 305, the engine bay might not be big enough, and you would have to be really creative with your headers.

[curtis73]

Not quite. Think of it more like this:

-Cranks turned down to 305 main journal size, undercut and polished rod journals = $450
-Pisons for 305 = $75. Pistons for 307 = $350
-Stock 5.7" rods resized = $45
-Bore and hone (necessary for new pistons) = $150
-hardware, gaskets, oil pump, bearings, silicone

That's about $800 and that's conservative.

For the $800 you would spend on bargain stroking a 305 could buy (literally) three or four running 350s. This is the main reason why I NEVER recommend hopping up a 305. As soon as you buy an Edelbrock intake for it, you've spent more than you would on a 350 practiacally. And, if you do the 350 you'll have a motor that will respond to bolt ons much better than a 305 because of the breathing problems.

I get the argument all the time about "well, its what I have." That just doesn't hold water these days with how cheap it is to buy 350s. I picked up a complete running 4-bolt 350 with only 18k on it for $250. Keep watching the papers and Craigslist.

But... if its what you want to do, then do it. Its your car and your money, so have fun... but no matter what the case is, the 350 won't cost you any more and its a vastly better platform.

And, a 400 is externally identical to all other small blocks, so it will fit just as well as a 305 would. Absolutely everything will be a bolt-in swap, from motor mounts to headers, to starter, even all your wiring and sensors. The 400 is just a small block, nothing different.