The Autopsy report is in from the “humbled/embarrassed” engine builder (myself)…

All the clearances were fine, it was totally my fault. I put the passenger side bank of pistons in wrong…. Instead of Exhaust, Intake, Intake, Exhaust, Exhaust, Intake, Intake, Exhaust…. I did the complete opposite…

So every intake valve was hitting the piston and probably bent everyone on the initial startup. I made the first pass and it went 7,500 and they all stayed connected but on the 2nd pass, 6.15 at 113mph, and about 800 foot the #8 intake valve head broke off and bounced all around and ended up in #1 intake port. The #8 valve guide ended up holding #6 intake open and the #8 valve seat ended up in #2 intake port so there was a lot of action going on inside the Intake port after the valve head broke a the #8 piston and then traveled back up into the heads. (it went a 9.66 on the first pass with every intake valve on the passenger side bent and not seating, so I bet it would have ran that 9.30 something I was hoping for…)

We heard a noise on startup but thought it was the rocker because we has some push rod clearance issues that I worked on after initial startup and it got much quieter, sort of sounded like the rockers were tapping the valve covers slightly but no, it was the valves hitting the pistons… Basically the noise had almost gone completely away because it was making its own clearance… I attributed that to the work I did to make clearance for the push rods…

From the picture below you can see that #8 head chamber is pretty badly damaged, but repairable. Every piston has shrapnel damage, every head chamber has shrapnel damage, every intake is bent on the passenger side head and I’m not sure if the valves are ok on the driver side yet but with the valve head lodged into #1, I’m guessing I may have bent a few valves on that head as well. Both heads will need some repair work done.

#8 piston has a hole in it and it’s split down the side (at first glance I thought it was the cylinder that was split) but I think the Block, Crank and Rods survived. I’ll need to check and possibly replace #8 rod since it was abused, I’ll check the cranks just to be sure, the #8 cylinder will need to be either sleeved or I’ll just need to bore all the cylinders to 4.50” bore, which is what I will probably do since I need new pistons and I’d rather not sleeve the block.

There wasn’t any damage to the oil pan or windage tray, there wasn’t any metal on the oil pan magnetic plug (most of the shrapnel was aluminum and stainless steel. There was some aluminum in the oil pump rotor so I’ll probably replace them if I can’t clean them up enough to be sure they are fine.

I was hoping I got lucky like I did when the motor blew up last fall and there wasn’t any damage to the heads except 1 bent valve. All I need to complete the KB short block is a set of rods and the mega block will need to be bored, new pistons and probably a rod. Both of those were option and I thought I might be able to swing so I could get another motor going for this season but with the heads damaged I’m going to need to repair or replace them and that will put me out for this year. (Frankenstein was going to be my back up motor once I got the KB motor done but that plan didn’t work out did it…lol

I am fortunate to have my wife ’68 Barracuda that runs 10 and is a blast to drive. So as long as I keep on her good side she will let me double up with her and still get to race some this year.

Moral of the story and what I learned from this experience….

I’ve probably built close 30 race motors and never had a failure, so I was over confident with the basic stuff like getting the pistons in the hole correctly and was more focused on the more technical/advanced items. So my over confidence and rushing to make the 1st points race of the year allowed me to learn a lesson the hard way. Yes the machinist was late getting the machine work done and getting the heads to me but that is no excuse for me rushing to build the motor and getting it into the car in 1 weekend.

I should have taken my time and made sure I did everything correctly, even the stuff I’ve done many of times and shouldn’t have to think twice about, it never pays to rush when you’re building a motor.