generally how long to chevy v8 small blocks last?

[bjhines]

I would like to get 5 years of HPDE track events and some street miles.

 

I looked at a lot of SBC crate options as well as custom builds. I managed to find a lightly used, well built 1964 Corvette 327 for a good price. I would expect to get ~300HP to the wheels.

 

I felt that the affordable crate motors were better suited to a heavy car with an automatic transmission. They are high on torque and low on the RPM range. The 383 engines just skewed TQ and RPM further away from what I wanted in a track driven 240Z.

 

All in all... I figure I can run the 327 on most any track without ever having to get into 5th gear. It should turn up nicely and survive the high RPM conditions much longer than a $5000 crate 383.

 

The fact remains, I cannot expect to get much mileage on any engine due to the conditions I put them through. My L24 powered 240Z track car has less than 20,000 miles on the last rebuild and it is getting tired. It is on it's 3rd oil pump and it's second waterpump. It has had as many as 10 oil changes PER YEAR. The camshaft is wiping several lobes(poor quality cam). And the front and rear seals are beginning to leak.

 

Track duty will wear an engine at 10 times the normal rate.

[sstallings]

I typically get around 150k miles between rebuilds on first generation Chevy small blocks as long as oil and coolant are changed at regular intervals (and that's hard use in much heavier cars with carbs). Most SBCs can be overbored twice if they are well maintained, so the blocks are good for 450k miles with rings and bearings. On the other hand, both of my L28 280Z engines are at about 200k miles with no measurable bore wear. As was stated in an earlier message, Datsun used iron with a high nickel and silicon alloy content to get very strong and long wearing blocks. Cadillac and Rolls Royce used to do the same. But all three of these (including the Z L28 engine) are more expensive to rebuild than a SBC when you do need to do it. The fourth gen LSx series GM engines are designed to last 200K between rebuilds and Chey has FINALLY gone back to high silicon alloy sleeves in the LS1v aluminum engine and the LQx cast iron engine blocks, so they should not wear like a first gen SBC. The other factor that contributes to cylinder bore wear is unburned gasoline washing off the oil in the bores due to overly rich mixtures, which was much more of a problem with carbs than with EFI. EFI engines should last 25-50% longer than the exact same carb'd engine for that reason alone.