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Old 10-21-2007, 10:38 AM
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327 with 76cc heads

how could you make good power with 76cc heads on a 327? what would the cr be with flat tops?what about a small dome?they are the 1:94 350/400 heads.

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Old 10-21-2007, 12:31 PM
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With the 1.25 dome pistons you will have 9.25cr . With flat tops you will have about 8.1cr that not to good . The engine will run OK with 8.1 but the cam you use needs to be smaller then 214 at 050 and less then 450 lift . Go with the domed pistons . I am building a 327 out of a 1971 350 block . To do so I am using a 1972 307 crank . I am also using 1.25 domed pistons . And a set of full ported 882 76cc heads . The cam that I am thinking of using is the GM 151. This is the factory 327 350 HP cam . Its 447 lift and 222 at 050 . I think with the ported heads this engine will have around 370 HP .
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Old 10-21-2007, 01:11 PM
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151 cam

Tango,that particular cam will fall flat at 5500rpm, there are a lot of newer cam designs that will out perform the 151. How do I know? had a 68 Vette with this cam and also a mild 327 in my 67 elcaminowith an aftermarket cam. Shop around a little and consult some engine builders,you will be glad you did.
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Old 10-21-2007, 01:19 PM
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so domed would be better huh...a 142 blower probably would work well with flat tops and these heads too...wouldnt it?
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Old 10-21-2007, 03:16 PM
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327

Is this an engine you're "building"? If it is, build it right to start with. Use decent heads, like a pair of true Vortecs. Domed pistons will be forged and cost more, while you can get decent hyperutectic flattops quite a bit cheaper and save some money to put towards the heads. Go the E-Bay route on parts and you can get things cheaper than jobber prices. Think about what you want, make a list, gather your parts, get your machine work done, and assemble it yourself.
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Old 10-21-2007, 03:37 PM
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agreed, junior stocker. Domes with big chambers is a poor way to make a performance engine.

Good heads, flat tops (or very little dome) and a smart cam.
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Old 10-21-2007, 07:06 PM
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Which 76cc heads do you have? Some castings are not even worth considering?

If you deck the block .007" and shave the heads right to the valve seats 68cc
using a .030+ flat top and a shim gasket you'll have a 9.55:1 cr.

You'll have to weight the total cost of this extra machining against starting with a different head. eg reworked #416 305 head, 350 TPI head (083 or 113) or other 64cc head. Again using a shim gasket.

Supercharging it is a very,very good option. A 76cc head would get you a 8.1:1 cr using flat tops and a .040" gasket. Good for 7psi on pump gas. But as above it depends on which head you have. Something like a 441,336(X) or 920 head with some hand porting and larger valves combined with a moderate blower friendly hydraulic cam would work very well with a 144ci blower and 750cfm carb.
Makes for a very powerfull, driveable and enjoyable street motor.
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Old 10-22-2007, 04:15 AM
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It sounded like the 327 that was being built was on a budget . You said you wanted to use your 76cc heads . The 125 cc domed pistons are available in cast . And they do make big power with open chamber heads . The 151 cam also works good up to 6200 rpm with new Z28 springs . Sure there are better cams but they are more costly . If money is not a problem then I think the best cam for street / strip is . Comp cams xtreme energy 262/270 der462/469 lift . If you go any bigger then this your car will be a dog off the line . 327s are great at say 20mph and up but they are and never will be a 350 ! If you still want to spend more money then go with forged flat top 30 over pistons . Also install ARP rod bolts . Use the world sr torquer heads with 67cc 202/160 valves . Go with a Weiand stealth intake Holley 750 vac secondary carb . This will be a 327 that will burn the tires .
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Old 10-22-2007, 09:34 AM
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be sure to clean up the edges of the domes too- sometimes thhey're left rough and the edges are great hotspots- bad for detonation. It will work, and it can run really well for a 1980's engine, sure today we have a lot more techology, but it will still be fun and less costly than a new tech engine. Be sure to use small diam. long tube headders and a good dual plane intake like the RPM AirGAp or even the Performer (which would allow EGR). Hell even the old "Z28" manifold would work great and is probably the cheapest performance manifold out there.

so basically with the budget parts you want/have

327 long block
151 cam
souped up factory HEI
domed cast pistons
ported z28 manifold
cheap long tube headers
and around a 650cfm carb

That looks like a really good fun per dollar return. just don't spin it above 6,000 rpm.
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Old 10-22-2007, 06:22 PM
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Quote:
Originally Posted by F-BIRD'88
Which 76cc heads do you have? Some castings are not even worth considering?

If you deck the block .007" and shave the heads right to the valve seats 68cc
using a .030+ flat top and a shim gasket you'll have a 9.55:1 cr.

You'll have to weight the total cost of this extra machining against starting with a different head. eg reworked #416 305 head, 350 TPI head (083 or 113) or other 64cc head. Again using a shim gasket.

Supercharging it is a very,very good option. A 76cc head would get you a 8.1:1 cr using flat tops and a .040" gasket. Good for 7psi on pump gas. But as above it depends on which head you have. Something like a 441,336(X) or 920 head with some hand porting and larger valves combined with a moderate blower friendly hydraulic cam would work very well with a 144ci blower and 750cfm carb.
Makes for a very powerfull, driveable and enjoyable street motor.
462624, 350/400 1.96 int
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Old 10-22-2007, 06:40 PM
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Pick up each head and march it right out to the curb. Do not pass go.
Find a set of #416 305 heads to work with. They are cheap and common as hens. ( often people wirll give them to you or give you a complete 305 with them on. They work very very well on 327's with home porting ( that you do yourself) and larger budget 1.94x 1.60" valves. they will need a valve job.
use a cheap flat top piston likethis one have the block "O decked". use a felpro .041" gasket
use Isky hyd cam #201271. Its actually less $$$ than the crane blueprint copy of the "151" cam and will make more power and torque.
use a hi rise dual plane (rpm) and a 650carb.
use a champion RV8C spark plug in and Lunati 73943 valves springs on the 416 heads.

You'll be grin ing.
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Old 10-22-2007, 06:45 PM
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you can use the 624 casting junk heads to learn to control the porting die grinder in the ports and bowls. Then, throw them out. then port the 416 heads.
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Old 10-22-2007, 07:25 PM
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i have a set of 305 heads, and the originol 210hp 327 heads. give me a second and ill see the cn of the 305 heads....."gone to see".....................................they are 14014416
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Old 10-22-2007, 07:45 PM
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Here we go again...........



tom
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Old 10-22-2007, 08:06 PM
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Quote:
Originally Posted by machine shop tom
Here we go again...........



tom
dude, im new to the game and trying to find out as much as i can about as much as i can. whats wrong with that? didnt you need help at one point or another? i mean awnsering questions is what hotrodders is all about isnt it?when you work for dimes and spend dollars, you want the most bang for your buck with what you already have.knowledge is power and im trying to use this knowledge to build as much power as i can! adam
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