Getting the Most Out of a 327 - Impala Tech
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post #1 of 16 (permalink) Old 07-28-2009, 01:27 AM Thread Starter
Ape
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Getting the Most Out of a 327

My 69 came with it's original 327 and I don't want to change out the block and I know that you can get a lot of the 327 than the 235 hp that it has now. I have seen some listed as high as 375hp. With that being said, what do you suggest parts wise I should be looking for to beef her up without blowing her up?

Ape Out.

Make: Chevrolet
Model: Impala Custom
Year: 1969
Doors: 2
Engine: 327 V8
Trans: Powerglide
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post #2 of 16 (permalink) Old 07-28-2009, 08:48 AM
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Gotta know how much you want to spend bro'.

I'd drop a 3.75" stroke crankshaft in it and a nice Performer RPM intake and the carb of your choice, vacuum secondaries, 650-750cfm, and 1 5/8" headers with a 2.5" dual exhaust. Double-hump heads would be nice, else there are some cast-iron ones available from places like World Products that are a relatively cheap/good upgrade.

It's fun spending other people's money. lol.

HOW A NOVICE REBUILDS A 66 IMPALA CONVERTIBLE:
http://www.impalas.net/forums/blog.php?u=1432
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post #3 of 16 (permalink) Old 07-28-2009, 11:29 AM
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I agree on boring and stroking the 327 to get 383 cubic inches under the hood. I just can not agree to anyone using double hump (camel or fuelie) heads on a modern SBC. They were developed back in 1958 (when everyone used Brylcreem and had a duck tail hair style).



Use a modern Vortec head with a Vortec RPM Air Gap manifold and a 750 vacuum secondary dual feed Holley carb with a 206-210 duration retro fit hydraulic roller cam at about a half inch lift (all ZDDP is now gone from motor oils and your chance to ever use a flat tappet cam went with it so go ahead and budget a retrofit cam into the budget).

Big Dave
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post #4 of 16 (permalink) Old 07-28-2009, 01:38 PM
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I assumed there is a chance he had the double humps already. I was thinking the Vortec and World Product or even the Racing Head Service heads (cast iron) would flow about the same.
It's all about the benjamin's at that point. Double Hump, RHS/World Products, Vortec, then full on aftermarket like AFR, TFS, Brodix, etc.

The roller cam is a nice touch too, but be prepared to spend around 600 coins for the cam, retrofit kit and installation at a shop.

If you prefer a standard flat tappet hydraulic cam, you can buy the ZDDP additive for the break-in from a cam shop like Competition Cams. Add to oil, run break-in as usual.
The Roller cam would give you *noticeable* gains in torque and HP over a flat tappet though, so you do get something for your money. Don't choke off that potential power with old heads though!


I gotta go re-apply my hair wax.

HOW A NOVICE REBUILDS A 66 IMPALA CONVERTIBLE:
http://www.impalas.net/forums/blog.php?u=1432
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post #5 of 16 (permalink) Old 07-28-2009, 01:42 PM
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would be funny to see the prices of what we're saying you should get. we're spending thousands of your dollars.

HOW A NOVICE REBUILDS A 66 IMPALA CONVERTIBLE:
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post #6 of 16 (permalink) Old 07-28-2009, 02:40 PM
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The early 375 hp 327's were fuel injected, solid lifter screaming beasts sold only in the Corvette. The 350 HP version made it into Chevy II's and are pretty rare. Your 327 is virtually the same engine but uses a large journal crankshaft and has a PCV system. (different block)

Going with Vortec heads on that 327 is a popular set up but those heads in stock form can only handle .450" lift cams. You have to mod the heads and get better springs to handle more lift or go with aftermarket Vortec heads alerady set up.
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post #7 of 16 (permalink) Old 07-28-2009, 03:44 PM
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Quote:
Originally Posted by Big Dave View Post
(all ZDDP is now gone from motor oils and your chance to ever use a flat tappet cam went with it so go ahead and budget a retrofit cam into the budget).

Big Dave
There are still a few oils with it. Shell Rotella is one of them, it's manufactured for diesel engines but Chevy High Performance did a write up on this same issue and said it was one of the best to buy for a hydraulic flat tappet motor, that or always use additive when you change your oil.

Quote:
Originally Posted by 1968 Caprice 396 View Post
Going with Vortec heads on that 327 is a popular set up but those heads in stock form can only handle .450" lift cams. You have to mod the heads and get better springs to handle more lift or go with aftermarket Vortec heads alerady set up.
OR you can buy the aftermarket springs for them for a little over $100, or even go further to use LS6 Gen III springs (have to use comp cam retainers and what not) to get a little more without modifying the head at all And I think it was up to .470-.475 stock form.

Dallas
1970 Camaro:

1988 Ford F350 Dually: It HAULS! Literally

1987 Iroc- LS1/T56 swap- sold

1967 Chevrolet K10- lifted, locked, 33's, OD Green- sold
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post #8 of 16 (permalink) Old 07-30-2009, 01:57 AM Thread Starter
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Thanks for the replies. I would like to get at least 300 horses out of it. That and throw in a 700r4 tranny and she will be one sweet sounding cruiser.

Ape Out.

Make: Chevrolet
Model: Impala Custom
Year: 1969
Doors: 2
Engine: 327 V8
Trans: Powerglide
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post #9 of 16 (permalink) Old 07-30-2009, 11:46 AM
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The factory stock 325-350 horse 327 was a fuelie headed (1.94"/1.60" with 64 cc chambers and 170 cc intakes), with a Rochester 750 cfm QuadraJet sparked by an electronic module, pointless distributor (the first attempt at HEI), and a very aggressive hydraulic flat tappet cam (casting number 3863152 with a vertical diamond cast into the core advertised duration of 342° with 0.447 inch lift) using rams horn 2.20" cast iron exhaust manifold. Difference in horse power was it was rated 25 horse more in the Corvette than in the Police Interceptor Impala because the Corvette is the leader of the fleet (and it has a 2.50" rams horn exhaust). The engine was also used a set of 11.0:1 pistons instead of the stock 10.25:1 pistons that the 275 horse 327 used.

As to price unless someone gives him a set of rebuilt three angle valve job fuelie heads the Vortecs are cheaper as you will not have to replace the worn out guides, or perform a valve job and the castings are about the same price since people keep inflating the value of a fifty year old cast iron head that they think will keep up in flow numbers with heads that were computer designed to reduce emissions by improving the combustion process (and oh yeah by doing that they designed the best flowing head on the planet at lift values at or below 0.350" lift).

I got my engineering degree shortly after these heads came out. I know what it is like to design things using a slide rule and your gut feeling about what works compared to a computer simulating flow characteristics from what we have learned about fluid dynamics since then (like breaking the sound barrier in jet powered aircraft, or going to the moon). It's time you stopped watching that old cathode ray tube black and white low resolution TV and joined the digital age of color plasma flat screen wall size units. Time marches on, time you did too; let the fuelie heads rust in peace.

Big Dave
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post #10 of 16 (permalink) Old 07-30-2009, 12:14 PM
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I think a set or world's product heads would be cheaper than Vortecs IMO (if bought new). Your talking $550 or so for new vortecs by themselves, then new valve covers because you can't reuse your old perimeter style, then self aligning rocker arms, Vortec style intake manifold. Your going to be in the 800-900 range after all is said and done and that's if you keep the valve lift under .475 or what not. I love Vortec heads (had them on a few motors) but on a budget, the world heads would be cheaper if you reuse the stuff you already have that's good. If you have to get a new intake anyway during the build, Vortec all the way. Shoot, even the new patriot aluminum heads are under $900pr assembled with guide plates and everything.

Dallas
1970 Camaro:

1988 Ford F350 Dually: It HAULS! Literally

1987 Iroc- LS1/T56 swap- sold

1967 Chevrolet K10- lifted, locked, 33's, OD Green- sold
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post #11 of 16 (permalink) Old 07-30-2009, 04:03 PM
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......and with a goal of only 300hp, you *could* still do that easily on the old heads if you wanted. All about your budget, really.

You'll reach your goal with any of the aforementioned heads. How much do you want to spend, and does it include a partial or full exhaust?

HOW A NOVICE REBUILDS A 66 IMPALA CONVERTIBLE:
http://www.impalas.net/forums/blog.php?u=1432
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post #12 of 16 (permalink) Old 07-30-2009, 09:48 PM Thread Starter
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I'm not really sure what I should spend. I have been out of the classic car market for years until recently.

Ape Out.

Make: Chevrolet
Model: Impala Custom
Year: 1969
Doors: 2
Engine: 327 V8
Trans: Powerglide
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post #13 of 16 (permalink) Old 08-05-2009, 10:55 PM
 
 
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the 275 hp 327 not 350hp 327

the 275 hp 327 came w1.94 int and1.5 ex in a 461 or a 462 or a 291
the 350 hp 327 came w2.02 int and1.6 ex in a 461or462or291or186or041
all with 64cc chamber
the 275 hp 327 was equiped with either quadrajunk or carter maybe also cast iron intake and milder cam by far
I have never seen a quadrajunk installed by factory on any 325/350 hp 327 all have winters castings alumium high rise intake manifolds.topped only with a holley.but i think dave is very close on cam specs for 327/325
or327/350
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post #14 of 16 (permalink) Old 08-08-2009, 11:24 PM Thread Starter
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I have a few updates. My Imp came with an Edelbrock 650 and a 3919803 intake manifold (4BBL off the 68 327). Looks like the intake was the same used in the 300/350 Corvette so there should be no reason to chance then I see.

Ape Out.

Make: Chevrolet
Model: Impala Custom
Year: 1969
Doors: 2
Engine: 327 V8
Trans: Powerglide
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post #15 of 16 (permalink) Old 08-09-2009, 08:01 AM
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Quote:
Originally Posted by Big Dave View Post
I agree on boring and stroking the 327 to get 383 cubic inches under the hood. I just can not agree to anyone using double hump (camel or fuelie) heads on a modern SBC. They were developed back in 1958 (when everyone used Brylcreem and had a duck tail hair style).



Use a modern Vortec head with a Vortec RPM Air Gap manifold and a 750 vacuum secondary dual feed Holley carb with a 206-210 duration retro fit hydraulic roller cam at about a half inch lift (all ZDDP is now gone from motor oils and your chance to ever use a flat tappet cam went with it so go ahead and budget a retrofit cam into the budget).

Big Dave

True , unless he wants the pure "nostalgia" look.
As far as oil not having any ZDDP:
READ THIS...
http://www.chevelles.com/forums/showthread.php?t=195620
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post #16 of 16 (permalink) Old 08-15-2009, 11:21 AM
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Quote:
Originally Posted by 68 custom View Post
the 275 hp 327 came w1.94 int and1.5 ex in a 461 or a 462 or a 291
the 350 hp 327 came w2.02 int and1.6 ex in a 461or462or291or186or041
all with 64cc chamber
the 275 hp 327 was equiped with either quadrajunk or carter maybe also cast iron intake and milder cam by far
I have never seen a quadrajunk installed by factory on any 325/350 hp 327 all have winters castings alumium high rise intake manifolds.topped only with a holley.but i think dave is very close on cam specs for 327/325
or327/350
the '68 L79 327/325hp used a Qjet and cast iron intake.

ape,
the '69 327/235hp heads are small valve(1.72) and large chamber(70or74cc). a switch to 1.94/64cc heads would be a big help.
the 3919803 intake was used on the '68 L79 as well as all '68 Qjet equipped 327 and 350s, 250 thru 350hp engines.

'69 2dr post 454 4spd
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