273 Stroker for ***** and giggles

[justinp61]

I’m surprised at all the naysayer’s here! So what if it costs a few bucks you guys sound like a bunch of wives cackling away. I think it’s a cool project the only concern I have is the same issue the /6 has with spark timing. The small hole long stroke means you have a smaller window to fire the spark down the hole, aluminum heads would help here.
I’ve got a 455hp 292 cid 289 in my 64 Fairlane yes I’ve herd plenty of naysayers also.
Have fun good luck

It’s because they’re comfortable in their little box. It’s fun to color outside the lines!

 

[justinp61]

The only reason why I know to stroke or even to build a larger displacement is to lower the powerband rpm.

I’ll assume your speaking of two engines making the same power.

 

[Garrett Ellison]

Anyone here ever sonic test a 273 to see what it could bore to? Or maybe have a picture of what it measures between cylinders through the core plug holes?

 

[273]

Anyone here ever sonic test a 273 to see what it could bore to? Or maybe have a picture of what it measures between cylinders through the core plug holes?

People told me when I was looking to do a 273 you can open them to 3.75 which would give a lot more piston options, but I don't know if you really can.

 

[toolmanmike]

People told me when I was looking to do a 273 you can open them to 3.75 which would give a lot more piston options, but I don't know if you really can.

Yep, .120 might be a stretch. Sonic check anything over .030. (I know many were bored .060 without checking) There may be a lot of core shift in those.

 

[Garrett Ellison]

The smallest LS pistons are 3.78, so that would almost certainly make that a no go. Cheap used NASCAR rods and forged LS pistons would possibly make a 4-1/8 inch stroke on a 2 inch or Honda crank pin viable. I do know that a four inch crank with decent heads (Edelbrocks, to be specific) is very responsive and revs very happily in the 390 inch variants. Even though it will shift the point at which the torque band starts lower in the rpm range, if you put enough cylinder head on it it’s still going to keep pulling at high rpm. I like a set of J type heads (casting # 974 especially so!) with the 11/32 stem 1.94/1.60 valves.

 

[273]

The smallest LS pistons are 3.78, so that would almost certainly make that a no go. Cheap used NASCAR rods and forged LS pistons would possibly make a 4-1/8 inch stroke on a 2 inch or Honda crank pin viable. I do know that a four inch crank with decent heads (Edelbrocks, to be specific) is very responsive and revs very happily in the 390 inch variants. Even though it will shift the point at which the torque band starts lower in the rpm range, if you put enough cylinder head on it it’s still going to keep pulling at high rpm. I like a set of J type heads (casting # 974 especially so!) with the 11/32 stem 1.94/1.60 valves.

With a 3.78 bore and a 4 stroke would give you 359 Cid so basically a small bore 360 even a 3.58 stroke gives 321 few over a 318, to me if I was gonna build a 273/318 would be cause I would want to run a 3.31 stroke, if your gonna stroke it might as well stroke a 340/360. Instead of a small bore version of something we already have is that really building something different ? I can kind of see if your shooting for 400hp 273 and trying to keep peak power under 7000 rpm a 3.58 stroke might be the way to go plus gives a lighter piston. To me if cost wasn't an overly concern I'd bore it large as reasonably possible keep stock stroke pick a rpm high as I'm willing to make peak power build it for that and it makes what it makes.

 

[trapster]

Are the bores heat treated on blocks ?

 

[toolmanmike]

Are the bores heat treated on blocks ?

no.