I am finishing my Late uncle's 33' Chevy Master 4 door and would appreciate some Knowledge. It has a 67 turbofire 327, MA suffix, That Runs well, but not very impressively. I bartered a set of "601" 305 HO heads that have been ported to match felpro gaskets, valves are 2.02/1.60 with 1.5 roller tip rockers. I pulled the heads off my brother's running engine, so I know they are solid. Chambers measure out to 58cc. What pistons would have the proper valve reliefs? I Keep hearing to avoid 305 heads on a 327???? I am not buying aluminum heads, I know they will destroy these heads, But I want to use these heavy iron 601s. Because I like them. I have a set of Keith Black #120 30 over Pistons? From the same engine. I will be having the block machined, so boring 30 over is an option. I know someone here has done this before, or Knows exactly what I will need to use these heads on this engine. I genuinely appreciate that knowledge. Thank you.
What heads are on the 327 now? Valve clearance is greatly dependent on valve lift. It has been my experience that 2.02 intake valves contribute little to what we generally do. I am not familiar with the KB pistons that you are looking at. 305 heads with 2.02 valves seem a little iffy to me. Pete
The KB120's won't work since they're made for a 3.48 stroke 350 crank. If you go with a flat top w/2 valve relief piston (5cc relief) you'll have 9.9 compression ratio with 58cc heads and a .041" gasket (with pistons down .020" in hole). 64cc heads would be 9.25 compression so unless you can live with 10:1 compression you'll need pistons with about 6cc more dish/relief. Now, with enough cam and proper piston/head clearance you may get by at 10:1 on premium fuel but be careful and get the machine work right or it'll ping itself to death.
stock replacement 327 pistons might work....they tend to sit pretty far down in the hole. I recently put a 327 together with this type piston, with the original power pack heads (1.72 intakes), and it only pings much when I get to low elevations, and then only while getting moving, not while at speed. And mostly only on 87 octane. In Colorado, with the elevation, you could probably get by fine with them. I live at 4500 ft, which is kind of similar, and doesn't ping here on 87. You can get the forged version if you want to spend some money, but that doesn't really sound like part of your plan. The big concern I'd have is that the 305 heads are so frickin ugly on the ends, compared to the old PP or FI heads.
What about this.......do some porting and smoothing on the 305 chambers. Smooth off any sharp edges and corners on the pistons also. Pick a dirt-track style camshaft with a lotta over lap and a tight LSA (108*). The big overlap will bleed off some of the compression at low speeds where pinging might occur. Tune the distrib. with lotsa initial ignition and total advance around 36-40* all in by 2500 RPM. Use 92 octane fuel...Use a 160 degree thermostat....A manual ****** would be a plus for controlling possible pinging. Clean your drawers often after driving this puppy cause it should scoot !!! 6sally6
The Jalopy Journal
