Rebuilding 1963 327CI 340HP engine

[Ray C.]

Hi!

Looking for recommendations for what part specifications to use in the rebuilding of a 63-340HP engine. (Cam, pistons exct) I would like to burn 93-octane pump gas.

Thanks for nay help!
Ray

[Brian Monticello]

DUKE - I'LL save you some typing time

I grabbed this from one of the forums - it was created by Duke Williams

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LT-1 cam for sure and the Speed Pro (nee TRW) replacement pistons from Federal Mogul. The pistons should work okay with a .040" composition gasket as this will give a true CR of about 10.5:1. You also have the option of having the dome machined off if you want a bit less compression. You may be aware that most '63 SHP/FI engines were assembled with two (.015") steel shim gaskets per side due to detonation complaints on these high compression engines. The change to two gaskets was done fairly early in production and was the field fix for single gasketed engines where the owner complained about excessive detonation going back to the '62 models equipped with these engines.
The LT-1 cam has very similar idle vacuum characteristics and idle quality to the original Duntov, but it will make more torque across the range, and I recommend this cam for ALL mechanical lifter SBs including those with the 30-30. The 30-30 has much more overlap. It will make marginally more top end power, but kills the low end torque big time.
My older Speed Pro catalog shows TP245 for the LT-1 cam (3972178), but this number might have changed. The forged 1/8" domed pistons are LF2166NF-XX where the suffix is the overbore - 20, 30, 40, 50, rf 60 thou. Go with the minimum overboard to clean up the cylinder walls. You should be able to go 20 or thirty at the most if the engine has not been previously overbored.
Check all these part numbers for availability with a Speed Pro dealer. You also might find some of them listed at www.federalmogul.com.
Select a machine shop that will do it YOUR WAY. DO AS LITTLE MACHINING ON THE BLOCK AS ABSOLUTELY NECESSARY. Boring and properly honing the bores for the type of rings - usually moly faced - is all that should be necessary. Don't let them deck the block and align bore the main bearing saddles, "just because they always do that." If that's their attitude, take you job elsewhere.
When the heads are off, measure the piston to deck clearance BEFORE disassembling the short block. If it's consistent down the line, the decks are likely parallel to the crank and decking is not required. RESIST HAVING THE BLOCK DECKED WITH YOUR LIFE. Most shops like to deck blocks to insure that the surface is parallel to the crank, but good shops have fixtures and tools to measure, and if they are parallel, which they usually are, it's okay to bore with a boring bar that indexes off the deck. Better shops have boring equipment that indexes off the crank centerline, so even if the decks are a bit off parallel the block can be bored dead perpendicular to the crankshaft axis.
If the block deck, main bearing saddles, and head surfaces pass the machinist's bar and .0015" feeler gage test, they DO NOT need to be machined. A compostion gasket will stand about .003" warp.
My simulation work has indicated that there is some benefit to opening up the exhaust valve seat to accept a 1.6" exhaust valve, but DO NOT open up the inlet seat to accept the 2.02" valve. The gain is marginal and the larger inlet valve will have more tendency to cause a crack between the valve seats.
Pocket porting and port matching the head to the inlet and exhaust manifold is time/money well spent, and a three angle valve job with .040" inlet seats and .060" exhaust seats will yield both good flow and good seat longevity.
Essentially all the parts you need for the rebuild are available from Federal Mogul/Speedpro/FelPro. These are all OEM equivalent parts. Avoid using "hot rod" parts. Use the companion Speed Pro mechanical lifters. Any valvetrain components should be replaced with OEM or equivalent. The LT-1 cam used the same valve spring as all contemporaneous small blocks. It's a bit different that the '63 springs, so use 1970 model springs. YOU DO NOT NEED AFTERMARKET HIGH RATE SPRINGS WITH ANY CHEVROLET CAM. The LT-1 cam has mild action and will work okay with pressed studs as long as the engine has no history of pulling them with the Duntov cam. Use stock valvetrain components for best operation and long service life.
My stock '63 L-76 yielded about 300 HP on the Desktop Dyno 2000 simulation program and this was backed up by someone who had a stock rebuild '63 L-76 dyno tested at 304 HP SAE gross. With the above changes my engine shows about 350 HP in the simulations, a 16 percent improvement. Peak torque is up about ten percent, and there is no loss of low end torque. In fact, it is marginally better. You should achieve similar improvements with your FI engine, and fuel metering should not be upset due to the similar low speed vacuum characteristics of the LT-1 cam and Duntov cam.
When you're ready to assemble, e-mail me and I will send you a document with the secret of how to properly adjust mechanical lifter cams.

Duke

P.S. Be sure to replace your vacuum can with a Delco "236" or equivalent such as the NAPA Echlin VC1810. This can was used beginning in early '64 on SHP/FI engines and its full vacuum advnance of 16* at 8" will greatly improve idle quality. The orignal '63 vacuum can didn't provide full vacuum advance until 16". This is okay for the 250/300 HP engine, but the SHP/FI engines only generate about 12" at idle ('bout the same with the LT-1 cam, only 10" with the 30-30), so the advance dithered around, which contributed to idle instability.

[Joe C.]

Re: Rebuilding 1963 327CI 340HP engine

Ray:

If you build it "as built" by Chevrolet, then it will run on ordinary, 93 octane "hi-test" gas. Federal Mogul's "Sealed Power" division has your 11.25:1 domed pistons, and, I believe, your "Duntov" camshaft. Instead of the double steel shim head gaskets, I would use a FelPro head gasket with compressed thicknesss of .036".
Others will add on shortly with part numbers. Please keep your engine's internals original, especially the camshaft. If you want the hardly perceptible horsepower gain of a "later and greater" camshaft, then why not pull your motor, store it, and install a ZZ4 crate engine.

Joe

[Irby G.]

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