Engine block class limitation

We have all seen classes that have cylinder head restricted class either by part#, iron vs. aluminum, OEM valve angles/placement, etc.
No particular form of racing, could be heads up drag racing, truck pulls or whatever.
For the sake of discussion what if there were no cylinder head constraints but were block limited? And I don't mean something with a manufacturer's part # such as a Ford A-460 block, GM performance parts, Mopar or whatever. An actual production PASSENGER CAR block which means engine size is more of a limiting factor instead of head design.
Also let's take it a little further with no block filler allowed; now we are really bore limited.

Now to the cylinder heads; no restrictions except for bore diameters and VALVE SHROUDING.
Which heads? Canted valve heads that move the valve away from the cylinder wall as the valve opens? C460/ profiler's with reduced valve diameters? Hemi heads?

Maybe restricted to flat tappet also as being limited to an OEM block and any head, RPM's would rule; being flat tappet (no mushroom type lifters) maybe the rotating assembly $$ would be kept down somewhat.
Sheldon G.

If the price of rotating assemablies where kept down, which is unlikely in a high RPM engine, then all the money would be spent on heads and valve trains to keep up with the higher RPMS. No winning with inexpensive racing it seems. I like the idea of trying to though. The guys I used to race with in the 90's that ran 468' and 472's back then are up to 700 and 800 inch stuff, and they are not happy either, and most quit because of it.

Think about only way is to have a spec engine or sealed crate and even then guys find ways to be creative. NASCAR uses flat tappet cams and they are more expensive than a solid roller. You can find OEM blocks that will go 4.5" bore and can jam in a 4.75" crank so those with money can still get the cubes.

Another good option is claimer engines. Let them spend all they want, someone will get a good deal!   

The block restrictions are similar to FAST rules a few years ago before the A460 block was allowed. Prior to that engine guys would bore out each hole and sleeve them to get the maximum bore possible.

The general direction that I see with the constraints is that the block is always the weakest link leading to major failures. If you restrict the use of production heads that will help mortality somewhat but those can be greatly altered as well.

You are suggesting making a class real expensive IMO

supervel45 wrote:If the price of rotating assemablies where kept down, which is unlikely in a high RPM engine, then all the money would be spent on heads and valve trains to keep up with the higher RPMS. No winning with inexpensive racing it seems. I like the idea of trying to though. The guys I used to race with in the 90's that ran 468' and 472's back then are up to 700 and 800 inch stuff, and they are not happy either, and most quit because of it.

I was thinking more along the lines of the valve train being the limiting factor in keeping the RPM's down. I.E.  spring pressure required to run X amount of RPM would limit (possibly) the RPM that could be turned with a flat tappet cam with any durability. The potentially lower RPM range would maybe allow for less $$ in the rotating assembly?

466cj wrote:Think about only way is to have a spec engine or sealed crate and even then guys find ways to be creative. NASCAR uses flat tappet cams and they are more expensive than a solid roller. You can find OEM blocks that will go 4.5" bore and can jam in a 4.75" crank so those with money can still get the cubes.

Another good option is claimer engines. Let them spend all they want, someone will get a good deal!   

Not sure, but I thought they used a mushroom tappet? Also, creative is good! 

Limit spring pressure, and to SS valves, with no hollow stems. I believe one of the members metioned this going on in Super Stock or one of the other threads, in some class. How about heads up Grude race, and just pick a car you think you can beat. Everyone that wants to see a race put their money in the pot, winner takes all. Not enough money, no race. Oh wait, how is the race track going to get a their cut? When you look at Stock, Super Stock, and Pro Stock, in the early years, compared to now, I don't think there is much hope for a cheap class everone can be competitive in for the budget racer. I guess that is why alot of people went to braket racing.

The index stuff is ok....(no, not SuperStreet, SuperGas or the like).  Heads up, no t-stops...pick a speed to fit your budget.  Around here, 7.0, 6.0, 5.70, sometimes 5.30 & 4.70 classes get a good car count and good crowd. The Super classes got silly when everybody wanted to be the 9.90 "rabbit" instead of the 9.90 "turtle".

dfree383 wrote:You are suggesting making a class real expensive IMO

We all know you have plenty of money  .

All kidding aside I wasn't really trying to suggest a new class configuration, I am getting closer to putting everything together again but want to upgrade. Either step up to aftermarket heads with an OEM block which would obviously be bore limited or go with an aftermarket block but keep my Iron heads. This was the 2nd part of my post regarding bore sizes and valve shrouding. I know the higher end heads are designed around a larger bore diameter but wondering about what can be done with a 4.40 bore.
Sheldon

we have alocal limited 8.5 tire class,must run a stock block with a bigblock.
i went with Aheads cause they are allowed with a 50lb penalty.
no Cheads or anything better allowed.
fastest pass yet is in the 5.30's-40's i seen in testing,and those were small block turbo or spray.
hope to have my combo done before long showem what a bbf can do.

STR-LGL-70 wrote:

dfree383 wrote:You are suggesting making a class real expensive IMO

We all know you have plenty of money  .

All kidding aside I wasn't really trying to suggest a new class configuration, I am getting closer to putting everything together again but want to upgrade. Either step up to aftermarket heads with an OEM block which would obviously be bore limited or go with an aftermarket block but keep my Iron heads. This was the 2nd part of my post regarding bore sizes and valve shrouding. I know the higher end heads are designed around a larger bore diameter but wondering about what can be done with a 4.40 bore.
Sheldon

  if you are talking about putting Say p51 or SCJ heads on a stock block the bore sizes are fine. Even the better heads like A460 and Even C460 stuff will work. Just watch the valve sizes and on the C460 stuff watch you clearance to the bores. It's all been done before!