Power Options for 327 - Team Camaro Tech
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post #1 of 10 (permalink) Old Nov 21st, 16, 11:12 AM Thread Starter
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Power Options for 327

I am planning to rebuild a 327 from scratch and wondering what my power options are for this cubic inch spec, and therefore what components would be required. I don't want to be picking individual parts for this build, I'd rather go with a proven, know assembly of parts for both bottom end and top end. I know Edelbrock sells top end kits, but are there others?

Any info would be appreciated.

Thanks
Mark
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post #2 of 10 (permalink) Old Nov 21st, 16, 02:07 PM
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Re: Power Options for 327

Do you really want to rebuild that one? There are some really nice GM engines from JEGS. There's a short block 350 HO that will end up at 333HP.

'68 RS
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post #3 of 10 (permalink) Old Nov 21st, 16, 02:12 PM Thread Starter
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Re: Power Options for 327

Yes, it's the original engine to my Camaro so that's the one I am rebuilding.

Does JEGS have rotating assemblies and top end kits?
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post #4 of 10 (permalink) Old Nov 21st, 16, 07:09 PM
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Re: Power Options for 327

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Originally Posted by 68camarors View Post
Yes, it's the original engine to my Camaro so that's the one I am rebuilding.

Does JEGS have rotating assemblies and top end kits?
Yes they do, but for the same money you can build a 383 cube 327 and no can tell what it is as the stroker crank is hidden inside the motor. Might as well go that route as every one else has and will assume yours is a 383 as well despite any protests you make to the contrary.

The most powerful 327 was rated a 360 horse in the Corvette if I am not mistaken (I frequently am as I have forgotten more than I would care to remember).

You can easily hit one horse per cube with a SBC, a little effort (cash is all you need) will buy you a 1.5 horse per cube just bolting on parts. Get down and dirty with custom parts and possibly the addition of a power adder and you can hit 2 horse per cube that will give a BBC a run for it's money.

Keep in mind a 383 was the base Mopar big block engine used in Road Runners and other hot Mopar cars. A 383 SBC would give the road runner a run for it's money.

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post #5 of 10 (permalink) Old Nov 21st, 16, 07:56 PM
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Re: Power Options for 327

Just for my own education, can you build a 2 bolt main 327 that high?

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post #6 of 10 (permalink) Old Nov 21st, 16, 10:24 PM Thread Starter
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Re: Power Options for 327

I hear you on the 383 but I would know the difference and that would bother me. I already have a great 350 in the car, wanting to go back to the original motor. Wouldn't be right to go with anything but 327 at this point.

BTW, the 350 in the car now pushes out ~360-370 hp, runs great. I'd like to sell it once I have the 327 built. What's the best way to advertise/sell a running engine? And how much could it bring? It has big valves (double hump heads), edelbrock intake, hooker headers.

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post #7 of 10 (permalink) Old Nov 22nd, 16, 06:36 AM
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Re: Power Options for 327

Only difference between a 302, 327 or a 350 (or the 383 that Chevy never built) is the stroke. The longer the stroke the more torque the motor will make overall, and the lower in the RPM band that torque will build. It is torque not horsepower that accelerates a car. That torque is what your butt dyno tells you and defines a fun ride. A 302 can make 500 horsepower in race trim but it has to stay above 8,000 RPM to do it. 8,000 RPM launches will get you arrested in most states not to mention being hard on parts.

GM developed the 350 and the 400 small block in response to heavier cars requiring more torque to get them moving (the 1970-'76 Impala was the heaviest car Chevy ever made). The 350 is a 327 that is stroked to what the engineers at the time though was the maximum. The 400 proved them wrong when it came out with the 3.75 inch stroke used to build a 383 in 1970. The difference between the 400 and the 383 is the bore.

In my opinion you build an engine with the biggest displacement you economically can. This is especially true with a short stroke 4.00 inch bore block because to make the same horsepower with a 327 as you would make with a 383 you have to rev it to a higher RPM. Often above the physical limits of a hydraulic cam.

A hydraulic cam limits RPM for two reasons. First at higher RPM the lifter pumps up keeping the valves off the seat. You can not bill power with the valves open. Second at higher RPM you get into valve float because a hydraulic lifter will collapse under the stiffer spring rate required of a valve spring that can close the valve at RPMs above 6,000.

So you must be willing to settle for less power and less torque with the 327 because of today's gas that will not support the higher compression that the "classic" 327 had in the days of muscle cars. That 360 horse 327 had 11.0:1 compression with cast iron heads. It did however have a very aggressive for it's day hydraulic cam. The top dog 327 had 12.5:1 compression and solid lifters to rev even higher.

Horsepower is a function of torque applied over time (revolutions per minute). In racing, which is often a timed event, you must be willing to rev to the limit of the engines endurance to win.

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post #8 of 10 (permalink) Old Nov 22nd, 16, 10:03 AM Thread Starter
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Re: Power Options for 327

Thanks Dave, all true except that the 327 only has a 2 bolt main. 350 has 4, I think 302 does as well? Has anyone collected data on how much HP 2 bolt main block can handle?

Edelbrock has a RPM top end package for my 327 (heads/intake and cam) and they claim 410 hp. I understand the tradeoff with torque when you go high on the HP so I don't think I will take this path but can the 2-bolt handle 410 hp?

Thanks
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post #9 of 10 (permalink) Old Nov 22nd, 16, 07:39 PM
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Re: Power Options for 327

When I rebuilt my 327 we bumped the compression to 9to 1, installed comp cams extreme energy 262 cam kit, edlebrock performer intake, and a Holley 570 street avenger carb, runs really well, not super high performance but really fun to drive
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post #10 of 10 (permalink) Old Nov 22nd, 16, 07:55 PM
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Re: Power Options for 327

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Originally Posted by 68camarors View Post
Thanks Dave, all true except that the 327 only has a 2 bolt main. 350 has 4, I think 302 does as well? Has anyone collected data on how much HP 2 bolt main block can handle?

Edelbrock has a RPM top end package for my 327 (heads/intake and cam) and they claim 410 hp. I understand the tradeoff with torque when you go high on the HP so I don't think I will take this path but can the 2-bolt handle 410 hp?

Thanks
Mark
Block strength depends upon factors over and above the number of bolts holding on the main caps (which can be upgraded to four bolt using stock cast iron caps or to two bolt studs and angled bolts on aftermarket steel caps). In either case beside the machine work to bore and tap the extra holes in the block for the fasteners (whether stud and hex head bolts or just stock washer hex head bolts) you must also line bore the block.

Those factors are main web thickness, core shift, block material (truck blocks contain more nickel to make them tougher), and crank size as well as strength of material in your choice of the crank.

Historically a stock block has been limited to about 450 horsepower, but every one is slightly different. My 513 horsepower 406 SBC lasted a bit more than six years before breaking the stock '509 block in half.

By the way extra bolts to hold the main caps in place are to try and slow down the caps from moving around as much at high RPM. They all move (or walk) in the block journal. whether a two bolt or four bolt. A four bolt helps spread out the clamping force to keep the cap from deforming as much when it hits one side then the other side of the block as the cap moves from side to side in reaction to the torsional forces that bend the crank at high RPM.

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