Safe rev limit??

[Bill Musarra]

One thing that hasn't been addressed here is how nmuch H. P. you are making or want to make. A word of warning here. The small block 302's in particular are not designed to make 2 hp per cu. in.. If you do go after horse power to match your rpm, you will be courting disaster. From a few racer buddies, it is the block that will let go before the bottom end does. The case will literally split in half. They are not designed to take that kind of punishment. Most well built/designed valve trains will take the high rpm punishment, but you got to remember the torque curve runs out around 6-7k unless the WHOLE system is designed to go higher. The rotating mass has to be very light and in extreme balance to go above 7000. Just a thought.

Bill

 

[Lynn Larsen]

Case in point:

 

[Jac Mac]

Excellent photo Lynn,

Note how the split is up thru the main brg cap stud bolt holes, Earlier 302/289 production blocks are cast with more material in this area. This sort of failure can ultimately be blamed on accountants and efficiency types that seem to think that when you cut a few pounds of cast iron from each block you must remove it from a critical strength area. Blasted Beancounters!!

There has been info around suggesting that you should not overtighten intake manifolds due to the wedge effect, which as you can imagine could help the process of splitting the block from the top down also.

Jac Mac

 

[Lynn Larsen]

Jac Mac,

I have heard the same thing about bottoming out and over tightening main bearing studs.

Regards,
Lynn

PS Thx for the compliments

 

[CliffBeer]

Excellent photo Lynn,

Note how the split is up thru the main brg cap stud bolt holes, Earlier 302/289 production blocks are cast with more material in this area. This sort of failure can ultimately be blamed on accountants and efficiency types that seem to think that when you cut a few pounds of cast iron from each block you must remove it from a critical strength area. Blasted Beancounters!!

There has been info around suggesting that you should not overtighten intake manifolds due to the wedge effect, which as you can imagine could help the process of splitting the block from the top down also.

Jac Mac

Hey, go easy on the accountants. Somebody has to ensure that businesses stay profitable, otherwise people don't get paid and businesses go bankrupt.

If an engine does need to be produced more cost effectively, it's the engineers who need to advise how to make it so. Apparently the engineers for this particular series of 302 weren't on the top of their game.

 

[Jac Mac]

Hey, go easy on the accountants. Somebody has to ensure that businesses stay profitable, otherwise people don't get paid and businesses go bankrupt.

If an engine does need to be produced more cost effectively, it's the engineers who need to advise how to make it so. Apparently the engineers for this particular series of 302 weren't on the top of their game.

Just to make you feel good Cliff, I think you will find that is the type of block
(case ) that you have in your 'crate' 302. Your idea of using a genuine ' race type' block as a foundation for the next motor is a much better idea.

I reckon any ' engineers' that played a part in the decision to revise the patterns for this block were of the 'paper & pen' variety. Ford seemed to go thru a' bad' patch with several production type's around this period. The 3.8 liter 90deg V6 was really light in the main brg webs.

Jac Mac