Stroked 348 short block 427 vs a Z11 427?

1964SuperStocker

Well Known Member
Supporting Member 3
This question boils down to which is better: A bunch of stroke or a mix of bore and stroke? For this example build the two engines would have the same compression, cam specs, heads....The 348 with a 4 inch stroke should have plenty of low end grunt. The 427 in a Z11 has just a little more bore/stroke over a factory 409. I would think they would have little difference between the two but maybe there is something I'm not considering. The rotating mass inside the engines should be similar but one clearly has smaller pistons and a bigger stroke. The other has larger pistons and a little stroke. Just pondering why Icon decided to settle on the 427 number for their 4 inch stroke pistons for the 348. This is as much a 348 question as it is a Z11 427 question.
 

1964SuperStocker

Well Known Member
Supporting Member 3
Bigger bore = Bigger values
We all know the Z11's didn't have anything bigger than can actually be fitted in a 348. Mine has 2.19 in it now but I probably should have put 2.25 in. besides the question is directed at the short block set up. I'm trying to understand if throwing all of the extra cubes in the stroke has advantages over making the piston bigger/heavier and the stroke a little longer? When The cubes are the same size then which set up wins more and where?
 

1964SuperStocker

Well Known Member
Supporting Member 3
My guess is the 348 with a 4 inch stoke would have more of a gradual hp/torque slope over a Z11 that would have more of a balance between bore/stroke.
 

dakota tom

Well Known Member
Supporting Member 2
Bore makes horsepower. Stroke makes tourqe curve. Shorter stroke engines make the same hp as bigger long stroke engines but higher rpm.
Airflow is the largest factor in power production.
I think z11s got stroked to 427 cu in to meet sanctioning body limits. The cylinder heads made the power.
 

fourzeronine

Well Known Member
Just pondering why Icon decided to settle on the 427 number for their 4 inch stroke pistons for the 348.

A stock 348 bore with a 4" stroke = 427 cubic inches.

Bigger bore = Bigger values

Not only that, but it allows for less shrouding of the valves by the cylinder walls. Although, they may not have really been thinking about that back in the early 1960s.

We all know the Z11's didn't have anything bigger than can actually be fitted in a 348.

Don't the Z11 heads have a different/wider valve spacing than the 348/409 heads?
 

1964SuperStocker

Well Known Member
Supporting Member 3
A stock 348 bore with a 4" stroke = 427 cubic inches.



Not only that, but it allows for less shrouding of the valves by the cylinder walls. Although, they may not have really been thinking about that back in the early 1960s.



Don't the Z11 heads have a different/wider valve spacing than the 348/409 heads?
A 2.19 intake valve (same as the Z11) is pretty easy to get in even a little 379 casting head inside any 348 block. The real key with heads is whether putting bigger valves will gain where its needed per application. No sense in trying to put 2.19 valves in a 379 casting when you can buy some cheap 333's with 2.06 valves and get better performance than the 379 heads with Jumbo 2.19s. Either way 2.19's will fit in any 348 block with any head combination. Though I will mention no one has let me have a pair of Z11 heads to try and fit on a 348 block but I'm guessing there is probably enough material in the block to remove and make it work. A Z11 head on a 348 has been discussed in the past and the understanding then was only in an extreme RPM motor would that make any sense because 690/583's work well enough otherwise. Kind of a guess but there is probably enough room to make the valves fit in a 348 block though I wouldn't go with much lift.
 
Top