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Aluminum Heads for Mild 327?

37K views 50 replies 11 participants last post by  1Gary 
#1 ·
I am trying to decide between the Edelbrock E-Streets,Performer's and the AFR 180 Eliminator's all in the 64cc range with 180cc runners. These new heads are going to sit on top of the original 327ci. / 210 HP in my 68 RS Camaro that need's to be re-built,bear in mind it's gonna be a Semi Daily Driver,I'm looking for a mild small block(345-380HP) with a little lump to it...the car already has headers,HEI distributor and a Edelbrock Performer 2101 intake and Edelbrock 600cfm Manual choke carb that I was gonna use,maybe upgrade the headers actually. The stock 2-Speed Powerglide and i'm assuming the stock gears in the rear end are still in the car,any recommendations to wake the car up? Thanks for the help.

Carlos
 
#30 ·
Assuming you are going to use forged pistons I have done some calculations using ICON Forged Pistons from Keith Black. They are the newest thing out, my machinist recommended them to me when I did my 454 build last year. First set of calculations are 327 block bored .030 and decked to 9.005, 5.7 rods, IC792 FT pistons, Fel Pro 1010 head gaskets, Lunati 10030 HYD Roller Camshaft, Edelbrock Performer RPM heads and intake, and a 750 cfm carburetor. The static compression would be 9.796 and the Dynamic Effective Compression Ratio would be 8.465. This setup would produce approx. 390 hp and 412 lbs. of torque. The second set are 327 block bored .030 and decked to 9.005. 5.7 rods, IC793 domed pistons, Fel Pro 1010 head gaskets, Lunati 10030 cam, Edelbrock Performer RPM Heads and intake, and a 750 cfm carburetor. S/C 11.072 and DCR is 9.588 which I think is too high for the street. Flattops are the winner.
 
#35 ·
Obviously the cam is too small if the horse power is below the torque figure especially a 327
Another completely unfounded statement. If you don't like how the torque and hp numbers compare to each other then use the metric equivalents. The numbers will change, though the power won't.

Instead of worrying about torque at all just select a cam that produces the most power at the rpm that you'll be using. Peak torque is a relatively useless number, power at "X" rpm is what you really need for a valid comparison.
 
#36 ·
ap72,please learn the rule of 5252.
perhaps my wording is poor.A bigger camshaft applied to the above dyno sim test would make a significant improvement to the power the engine could make.
In terms I understand though not technical,the peak hp being 2 or more k higher than peak tq rpm will usually indicate higher hp numbers than torque.when you reach 5252 rpm,that is usually the x over spot,or it should have happened by then.There is hp being left on the table somewhere???

a 5500 rpm 327 though perky is no where near what it should do. a 1500 rpm range is too narrow for idael acceleration.In a perfect world you shift at max hp and the transmission drops the rpm to max torque rpm.not many transmissions drop 1500 rpms between shifts.
I wont post a detailed explanation like Bogie,that guy does a much better job of explaining the details
 
#38 ·
ap72,please learn the rule of 5252.


In terms I understand though not technical,the peak hp being 2 or more k higher than peak tq rpm will usually indicate higher hp numbers than torque.when you reach 5252 rpm,that is usually the x over spot,or it should have happened by then.There is hp being left on the table somewhere???

a 5500 rpm 327 though perky is no where near what it should do. a 1500 rpm range is too narrow for idael acceleration.In a perfect world you shift at max hp and the transmission drops the rpm to max torque rpm.not many transmissions drop 1500 rpms between shifts.
I wont post a detailed explanation like Bogie,that guy does a much better job of explaining the details
Again, there is absolutely no good information in any of this, BUT it does come from a long line of misunderstood BS, so it is understandable how a person may come to believe it carries some merit.

hp and tq always cross at 5252, there is no significance of that number though other than how hp and torque are defined, switch to metric readings and 5252 carries no significance.

To a certain point running a larger cam will produce more hp and it will produce it at a higher RPM... which means that if you don't ever run in that RPM the "increase in power" will actually make your car slower as it results in a loss of power in a lower RPM. Which is why you need to compare power output at the same specified rpm to get a better comparison.

For a perfect shift on a race track you do NOT shift at peak hp down to peak tq, you shift to maximize your average hp, meaning you shift past peak hp and fall to a place right below peak hp (how far in each direction depends on your power curve).

A 5500 rpm 327 maybe exactly what is needed depending on the application. If you run 50hp less than a more aggressively built 327 but are never in the rpm range it makes the additional power the engine with less power can actually make your car run a little faster.
 
#40 ·
cd,I agree with you,the roller would make more power.better duration for a 327 and more lift.The power would increase everywhere,including the bottom end. A bigger cam does not "always" mean a loss of low rpm torque. neutron meters and kilowatts are different ways of expressing something that humans can kind of understand.
and thanks for reiterating that a wider power band is required to match transmission ratios.
I no longer have a desire to argue here. 327s make power at higher rpms than 350s.putting a smaller cam in a smaller engine is not entirely accurate for rpms. duration is time,lift is flow,o
 
#42 ·
Well after many months the car is almost together,another couple Weeks...can't wait!

This is what I ended up going with:
327 bored .030
9:6:1 Compression
Balanced
Edelbrock E-tec 170cc heads.
Edelbrock RPM Air-Gap
Stock crank and rods
MSD Ready to run HEI Distributor
MSD Wires
Comp XR270HR Hydraulic Roller Cam
Comp Valve Train
1.5 Roller Rockers
Holley #4150 650cfm Vacuum Secondaries
1 5/8” Headers
2 1/2” Dual exhaust into flowmasters

Gonna put a TH-350 and 3.36 rear gears behind it...what kind of HP/TQ am I looking at with this combo?
 
#44 ·
What happened to the Edelbrock Performer Rpm heads? If I was building a 327 ci My choice would be the Edelbrock Performer Rpm heads with the matching Edelbrock Performer Rpm intake maniflod. I have read where people are having too many problems with the air gap manifold. You can do a comparison here on Hot Rodders forum between the Performer RPM and the Performer RPM Air Gap. On the rear gears I would go with 342's or 355's. That 327 needs to get the rpms up quick. Most people use 373's for the street and with OD transmission use 4:11 or 4:56. Good Luck, nice Camaro. It looks like a copy of my 67 RS/SS Camaro. 491 ci, TH400, 12 bolt 4:11 rear, Caltracs and frame connectors too. Front suspension replaced with Global West upper and lower control arms. Unisteer manual Rack and pinion also.
 
#45 ·
To be honest when I skimmed over this thread and saw 327 and aluminum heads the first thought that enter my mind was lean on the compression,build a RPM capable bottom end,cam it to buzz to the moon with heads accordingly to breath.Remember the Camaro's are heavy cars that need that to move them.
 
#48 · (Edited)
You know, sometimes you just hit a sweet spot and the OP has done just that with this combination. This little motor makes some very pretty hp and torque curves. Any of you guys who want a 327 that will pull away strongly from a stop and still haul the mail at the top, should emulate this combination. I used the flow numbers from the Stan Weiss site to run this Sim.....Dynamic Compression Ratio of this combo is 8.428:1.

RPM HP TORQUE
2000 138 363
2500 177 371
3000 226 395
3500 280 421
4000 331 433
4500 375 435
5000 407 428
5500 425 406
6000 415 364

Peak volumetric efficiency 92.7% @5000
Peak BMEP 198.7 lbs @4500
Maximize the combo by retarding the cam 4 degrees and pick up 9 hp and 4 ft/lbs of torque. 650 is just the right amount of carburetor.
Good job SSCamaro_510.
 
#50 ·
Man,those numbers are impressive! I'm not a drag racer by any means,I just wanted a small cube motor for semi-daily use to run on pump gas. Looks like I'll be going with the 3.42 gears instead. I can't wait 'til I'm back on the road in a couple Weeks. Thanks for that dyno Sim Techinspector.


 
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