Crank & Rod Bearings
I started by removing the oil pan to check the condition of the cranshaft and rod bearings. I can tell they are a little worn so I've considered replacing them. I asked about it on SBFTech and VMF but both suggested I just leave it alone based on the oil pressure readings I recorded about a year ago.
Camshaft
I checked the specs on the cam before removing the heads and cam. The intake had .230 lift at the cam (.368 at the valve) and .237 exhaust life (.380 at the valve). After removing the heads and cam, I found the number 560 stamped on the end of the cam.
A few internet searches revealed it is a Sealed Power 560 cam which is a stock replacement cam. The specifications on Summit match up to the stock cam grind referenced in Tom Monroe's book on SBF engines.
Intake Duration at 050 inch Lift: 184
Exhaust Duration at 050 inch Lift: 189
Duration at 050 inch Lift: 184 int./189 exh.
Advertised Intake Duration: 292
Advertised Exhaust Duration: 265
Advertised Duration: 292 int./265 exh.
Lifters
The lifters seem to be in excellent shape. There are no strange marks on the face which rode on the cam lobes. They slid easily in and out of the lifter bores. I took them out and put them in an old container in the proper order in case I ever need to inspect the lifter which came out of a particular bore.
Pistons
I noticed the bottom of each piston has the number 1157 cast into the skirt. I searched the Internet and found these are Keith Black Silv-O-Lite pistons. They are dish pistons but I could find no cc measurement of the dish size on the Internet. I emailed the company and they responded stating the dish is 12 cc.
I measured the bore with a dial caliper and it is bored 040 over. Once I cleaned off the tops of the pistons, I could make out a 40 stamped into the top of each of the pistons. I checked how far in the hole the pistons are at TDC. I used a gauge to get the piston to TDC. I then slid a feeler gauge under a piece of metal laid across the top of the piston. The measurement is rather large at .035.
I later learned this is because these pistons have a compression height of 1.585. Many pistons for a 289 have a compression height of 1.605. This would change the amount the piston is in the bore from .035 to .015. This paired with the dished piston gives me a current compression ratio of 8.17:1 which is shamefully low. Switching to any aftermarket head with a 60 cc chamber (or even the '69 351 heads) is going to drop compression even lower (to 7.74:1 with current parts).
The head gasket they used was a Fel-Pro 8548PT-2. It has a compressed thickness of .047.
Timing Chain
This isn't the best picture but the engine has single roller timing chain installed. The chain has seen better days as it seems to be a little stretched. I chose this picture as you can see the extent of the stretching on the far side of the chain.
Heads
I took several measurements of the 351 heads to make sure I order the correct valve springs. I removed all the valve springs with a tool I rented from O'Reilly. I noticed the valves seem a little loose in the guides. I also tested with water to find three valves which leak slightly.
I decided to check the 289 heads I took off and found they have four leaky valves. I took off a couple of springs and the valve guides seem a little tighter. A strange oddity is that the 289 heads do not have the bump in the exhaust port but the 351 heads do.
I've learned a fair amount about the condition of the motor. I'm not sure what I'm going to do with it at this point. There is the desire to have it rebuilt but there is also the concern that since it is already bored 040 over that that might not be an option. I think I'll take it to a local machine shop and let them evaluate what I'm working with an give me some suggestions.
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