Thread: 355 build HP and Torque?

Tweet

I went ahead and installed all the freeze plugs, 1/4" pipe plugs and the 3 drive in plugs in the front. I was thinking about tapping the front holes and using pipe plugs as others have done, but at this stage after everything has been cleaned and started to assemble, I decided not to take the chance of getting some of the metal filings in the engine. Instead I just drove in the factory type front plugs and staked them again with a chisel. The commonly forgotton drive in plug under the rear main bearing, I also forgot about and realized the original one was still in there. I didn't worry much about it as I had cleaned and blown out the oil passage fairly well all around it. I did measure down the hole where the oil pressure gauge normally screws in just to verify the plug was installed at the correct level to not cause any oil passage restrictions. It measured just under 8.5" inches down which I believe it correct.

Next step was to get ready to install the pistons in the cylinders. The KB piston directions say that for the type of hypereutectic pistons I have, the top ring gap should be .026" and the 2nd ring gap about .018". After placing a lone ring inside the cylinder, I measure about .015", so the ends would need to be ground. I decided to order a cheap grinder instead of manually filing them with a file.

While I'm waiting for the ring grinder to show up, I moved over and started working on the heads. The new Proform Tall Hite valve spring height micrometer I got needed to be modified to clear the wider valve seal bases on the vortec heads, which I did mostly by just trimming off a little material from the end of the inner threaded part. This reduced the tool's ability to read heights in the upper ranges, but still left it adequate for most typical uses I would need particular on most sbc heads.

Even though others have suggested I not lap the valves if they are already in good sealing condition, I felt more comfortable polishing them a bit with fine lapping compound to remove any rust or grit that may have accumulated in the last year since I disassembled the heads. I did a quick and easy touch up lap, with out removing much material.


After the lapping was complete and everything wiped clean, I miced all the valves to check existing installed valve heights. CompCams says for my cam and beehive springs I would need about 120lbs on the seat which could be made with a 1.75" installed height. After micing them all, most of them measured in the 1.77 to 1.78 range, with one near 1.79. I ordered a hardened shim set from Alex's which should be here any day. I assume I should shim each spring separately to match as close to the 1.75" as I can. The shim set includes thicknesses of .015, .030, and .060, I assume between the .015 or .030, I should have what I need.