Where can I find the casting code and what is the general opinion of these heads? It's a 327 block 3858174, needs a rebuild, getting a new carb intake cam setup, so how much horse power can I safely get with these heads and block?
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Re: my double hump heads
Remove valve covers, all info there. -
Re: my double hump heads
Chuck - the double hump heads are generally considered some of the best GM orignal casting heads...and they could have either the large or small intake valves, the only way to tell is to strip and check, there were markings on the line under the orange paint but that is probably long gone. There are have been lots of good suggestions on buildup of 327's here, using these heads, the GM 151 cam retarded slightly, etc. to get a great seat of the pants torque and acceleration from the 327. You may want to search in the archives....CraigComment
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Re: my double hump heads
Orig, crayon markings do survive. I found them on my heads and block.
Kevin
I have other photos if you wantComment
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Kevin: Head markings
Kevin,
What does that (HR? or HP?) head marking mean? The head has the 2.02" intakes? Also, what year are you talking about?
GaryComment
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Re: Kevin: Head markings
Gary -
Kevin's car is a '67 300hp A.I.R. Powerglide, thus the "HR" engine code; this code was grease-penciled on the head so the operator who stamped the pad knew what suffix gang-stamp to use (the pad was stamped after the heads went on). The same "HR" was grease-penciled on both sides of the block (upside-down in car position, as the bare block was upside-down on the line until the heads went on) so the operators knew what innards to put in it (cam, rods/pistons, oil pan, etc.). These markings are generally visible on original, untouched engines under the paint, but disappear instantly when the block or heads are hot-tanked during a rebuild.Comment
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Re: Kevin: Head markings
Thanks John, Gary here is a shot of the block that John mentioned.
Block IDComment
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Re: my double hump heads
Everyone has pretty well answered the numbers questions on your engine but I haven't seen an answer to your horsepower question.
In stock form, these pulled over 300 hp SAE Gross. If you have the 2.02 valves, then you could have gone up to the 375 hp range stock.
If you are rebuilding, then you can do several things to get more. However, most work needs to be done to the moving mass and the bottom end. Improved rods, better balance, lightening of components, and porting of the heads will let you go much higher.
With a 3892667 block (still two-bolt main) and -461 heads, we built a 302 that we road raced at 8500-9000 rpm and made around 450 hp gross.
If you are looking only for horsepower and not originality (outside the scope of this list), then you can forget the -461 heads and go with several of the aftermarket aluminum heads and get as much power out of the box as you can with $1000 of porting on the -461s.
So your block and heads won't limit the horsepower you can get within reason; your pocket book will.Comment
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Re: my double hump heads
My goals for the car, well, here we go ... it's a driver not a show piece - so far the block, paint, and interior are completely incorrect - it sustained heavy interior damage from water when the last owner left it outside for years in St. Pete - the A/C compressor and brackets I have but the rest is missing - the defrost fan box is rusted through - the entire braking system needs replacing - I just hope the rearend, tranny, and frame are OK - it's been sitting in my garage for 18 months waiting for me to find the cash - so far I have none - I paid just 5000 for it so I can put alot into it before I am upside down in value - I want to get it running and make it look respectable - My cousins have a 67 BB and a 69 BB with bunches of horsepower so I don't want to be too far behind them - So I am going to do the brake work first so I can at least park it on my sloped driveway without losing it, build the motor up as far as possible without needing all highperformance stuff I can't afford, it's the wrong block anyway - want to barely keep it on pumped gas - drive it so I can see what else it needs - I'm going back to the correct interior (replica) - keeping the paint probably for several years - joining the local Tampa vette club - cruising to Sunday breakfast as fast as I can go light to light. There you have it. Please continue with any advice and comments you have. Thank you.Comment
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What is the blue paint for under the yellow marks? *NM*
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Thanks Kevin & John *NM*
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Re: my double hump heads
Hello Jim, thanks for the e-mail. So you had a 64 air car? You and I are a shrinking crowd. Do you have any pictures left over? I am really at a loss for now with what to do here. My problem is budget. I have none. And, a lack of experience with what the different horsepower ratings feel like to the driver. The only high power car I have any real time in was my neighbors 99 coupe he sold a few months ago. 345 stock HP boosted maybe to 375 after the new airbox and exhaust. It was a 6 speed and a C5 so it really stayed hooked to the ground. I know a mid-year can't hook as well with skinny tires but after it gets rolling the HP begins to matter. So, I just don't have any idea of how far I want to take my 327. I don't know if I will appreciate, say, 400HP over 300HP or not. How well did your 64 run? Was it "push you back into the seat power"? What do you drive now? I need to figure out how much HP I'll need to be happy, how much would be wasted overkill, how much I can afford to build up to even if it doesn't help, and just plain how much can I afford, as well as what the real possibilities are with my parts vs needing better parts. Joy, joy. Your thoughts? Anybody else reading this PLEASE respond.Comment
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