Ok I have been to the archives and really think there are a lot of you out there that can help me. So I pull the engine. I take a look at the condition inside and out. I replace the timing chain and gears, oil pump, distrib gear.

Can I (without putting too much pressure on the existing parts):

1. Do a valve job
2. Re ring it (without a bore job just a hone)
3. Replace the main bearings (without turning the crank)
4. Replace the cam to get a little more HP
5. Replace the lifters

Basically I would like to get another 50K out of the 110K I have now and then drop in GM crate maybe. I read about testing the engine out of the car for leakdown and pressures and that sounds like a good idea. Not sure if a shop around he can do it though. The way I figure it I'll have some fun and maybe enjoy a few more HP until it's time for a new engine.

 

I'd say yes to 1,4&5.
2 & 3 are maybes. To resolve the question involves measurements that most DIY'ers should leave to a qualified engine rebuilder.

 

Hi Dave
I did basically what you're thinking of doing. At around 92K miles I pulled the engine out of my 74 and examined it. I used snap gauges and a micrometer to measure the bores and found that they were still within factory tolerance. Same with the crank. The heads were shot and I elected to put a set of World Products SR Torquers on instead of having the heads reworked. I got the 67cc chamber versions to build a little more compression and I ordered them with 2.02 x 1.60 stainless valves. They cost me about $450 and I think it was well spent. Only problem I had with them is that the hole was incorrect for the temp sender and TCS switch. I had to drill it out and retap it. I disassembled the engine completely and cleaned it thoroughly with degreaser and hot water. I used a set of engine brushes to clean the oil gallies. Getting the oil plugs out was a PITA but I managed. I cleaned the pistons and rods by soaking them in a container of parts cleaner overnight and they came out really well. I found someone who would knock out the old cam bearings and install new ones. I then honed the bores lightly with a hand hone just enough to establish the right pattern. I then reinstalled the crank with Clevite 77 bearings and measured the clearance with plastigauge. I was on the high side of factory tolerance but felt it was OK. If I wantedI could have returned the bearings and gotten a plus .001 set that would have gotten me tighter. As it turns out I've had no bearing problems. I reinstalled the stock pistons and rods with moly rings using an adjustable ring compressor.I then installed a Crane Max Velocity 272 dual pattern cam with a Cloyes double roller timing chain and also installed a Summit racing hi volume hi pressure oil pump. I buttoned up the oil pan and cam cover and that was the basic short block. I then installed the heads with Fel Pro gaskets and installed new pushrods, lifters and Summit full roller aluminum rockers. Except for the intake and exhaust manifolds that's pretty much what the job consisted of. I bought the book "How to Rebuild Small Block Chevy's" and followed what they said. I've been running the engine for a couple of years now and it's been great. I know I don't have an 11 second car but the engine is reliable, uses no oil and feels pretty good. I think it's probably around 250 net/300gross horsepower but I'm sure someone with a Desktop Dyno could give a better figure. The cost of the rebuild wasn't that bad. The $450 for the heads, about $150 for the rings, bearings, gasket set and oil pump and timing chain, around $100 for the cam and another $200 for the lifters, pushrods, and rockers. These are rough numbers that I remember but as you can see the cost was around $900 give or take a little and I've got an engine that should be good for at least another 50K miles with a nice performance boost. Hope this helps. :seeya

 

First things first! Prior to pulling the engine, it's a good idea to get compression readings and any other qualitative testing and inspections that can only be done while the engine is running. Have a good mechanic do this and give you a good report of your engine's weak and strong points. Based on his recommendations, develop a plan that will get you your goal of another 100 thousand miles.
One of the biggest causes of low oil pressure is ware of cam bearings. Don't overlook these, as well as cam lobe ware. Your timing can suffer much if a lobe or two has flattened even slightly. While your in the bottom end, main and rod bearings are cheep. If you pull a few rod and main caps and inspect the surfaces of the crank, you may find a fresh set of bearing shellls may do wonders for your longevitity.
If you have plug fouling problems, bad compression readings, high oil comsumption, etc., pulling the heads is inevitable. This past summer I spent a lot of time trying to find the best thing to do with my heads. I determined that, assuming you wish to keep the stock heads, send them to someone like Aerohead racing components of Indianapolis, Indiana (my favorite at 317 862-0223), or Powerline Engine company (1-800 722-4645). These guys are setup to do heads by the thousands and can do quality work, including new valves, seals, springs, guides and a three angle valve grind for under 4 hundard dollars.
If you find, after pulling the head, you need or want to re-ring, you really got to ask yourself at this point do I want to put all this work in a dirty engine? At the very least, I would go ahead and strip the block and have it boiled out if I were going to remove the pistons anyway. Heavy ridges or scoring of the cylinder walls and your looking at a .030 bore.
This would also be the time to send your Carb to Lars for an overhaul, and don't overlook your distributor.
Good luck!!