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Newbie help picking cam/intake combo chevy 327

13K views 13 replies 10 participants last post by  MouseFink 
#1 ·
Hello, new here, visited the site many times lately and must say lots of good info and members. I have a 86 c10 I bought about 3 months ago. It has a 327 , double hump heads. Its running at the moment a cast iron q-jet intake with q-jet, hei igntion. The guy I bought the truck from just had rebuilt the motor but for some odd reason put a "pulling" or Rv cam as its often refereed to. It makes good low end torque but has no lope at idle. I want a good street strip cam but do not know what to buy. After running the numbers on the block (the casting number and suffix code in front of passenger head), the motor is a l-75 1965 corvette 300 horse motor. A real shocker to me. I plan to change cams , put a high rise aluminum intake (not sure what brand yet , suggestions welcomed). So whats a good cam/intake combo. The specs are 65 327 bored .30 over, regular 4 eye brow pistons, double hump heads 1.94/1.50. Hei igntion.Running long tube headers into flowmaster 40 series , 3 inch all the way. Turbo 400 tranny no stall. I plan to go back with a holley or a q-jet. I guess the big thing is a cam that will work with no stall. Any suggestions deeply appreciated.
 
#2 · (Edited)
This engine should have the compression to tolerate and make use of a cam like the Comp XE268H. This sits at about the limit of a stock stall converter maybe a part step beyond. With camel hump heads an intake like the Edlebrock Performer RPM with a 670 to 750 CFM carb this will easily make 350 - 360 horses under 6000 RPM with a robust torque curve on the lower end. It has a moderate rumble at idle, not rasty but enough to tell anyone listening that the engine is pulling some cam. This cam and cams like it need the recommended spring kit. However, a lot of guys substitute beehives or conicals which will work with this type cam. These springs need a smaller diameter retainer and you have to be careful to size the locks to your valve's stem diameter as newer engines that use these springs have metric sized valve stems which are not the same diameter when converted to USA measures as your current valve stems.

I recommend that you select the intake for the carb type you intend to use that being square bore (Holley/Summit or Edlebrock/Carter) or the Qjet spread bore. While you can mix square bore and spread bore manifolds and carbs with an adapter, I find that this is less than fully effective as a means to develop top end power than if the manifold flange configuration and the carb base naturally match.

Bogie
 
#3 ·
not a big fan of a short stroke engine in a fat truck.If you can get the correct information about the rebuild and specifications of the assembly work,then you can choose a good cam/intake combo. If rebuilder pistons were used and compression is down then you might have the correct camshaft now. If you insist on changing the cam anyways,choose shorter duration and tighter ICL. also seriously consider using a hydraulic roller cam,a little more money and a little more power.
If you insist on having a choppy idle over have power first,then choose a cam with a little more exhaust duration(and tighter icl)
 
#4 · (Edited)
Im going to be realistic with you, I don't mean to hurt your feelings but its a realistic opinion.
You didn't list your rear axle ratio. This is important. Most times "street/strip" means more rear gear, and an engine built to perform at those higher RPMs. If what you want is a rumpity-rump idle for boulevard cruising (which is perfectly fine in my opinion), you might actually have a truck that performs worse on the street than it does now. A generic RV-grind is fine for a street 327, especially with street friendly compression and unknown rear gears. No lumpy idle, but lots of bottom end for fun on the streets.
For me; personally, fun street cars are all about the midrange RPM. Something in a Comp Cams 262H type grind would do fine.
Bogie's 268H-type grind is going to idle more aggressively, but you really want to bump up the torque converter. I'd avoid the TCI and B&M budget ones. Call the guy at Freakshow in Abilene TX. He builds some VERY nice TC's for about $400.
Intake:
Performer RPM, Holley 300-36 (also known in the 90s as the Contender), Weiand Stealth. No reason to go to the chinese copy stuff, there are plenty of the above intakes available for the same price. I got a Contender for a few bucks from a pawnshop LOL.
List the casting number on the QJet intake; you may have a good one already and the QJ will support all the power that iron headed 327 will ever make and then some.

Some other thoughts not directly related to your question:
Get rid of the TH400. Best thing you can do. Not that its a bad transmission; but its HEAVY and it eats a lot of power. TH350 or 200-4r overdrive. You don't need dual 3" exhaust; in fact, you could run a single 3" with a GOOD Y-pipe, look more sneaky and perform great

Your 327 is like bringing a .38 revolver to a gun fight. You can work with it, but you have to be better with it. If you want to do this as right as you can without tearing down the block; Trade TH400 for TH350, Howards roller cam conversion, Pro-Filer or Jegs house-brand aluminum heads, Holley Contender/Performer RPM/Weiand Stealth, Holley 3310 carb or something similar from AED/BLP etc, good 2.5" exhaust, 3.73 rear and the appropriate torque converter. You'll also want to recurve your distributor.

You can do most of this using the heads you already have. If you have a GOOD Qjet intake, Id put the money into the roller cam conversion, some good rocker arms if your camel hump heads don't have any, and the torque converter. Step 2 would be the performance carb and intake. Step 3 would be quality aluminum heads, lightweight valvetrain.

Option 2: just get a Vortec crate motor, put in a roller cam, buy the vortec version of the intake you want and make better power, cheaper
 
#5 ·
If you'd spend your money on a looser converter and some shorter rear gears, you may find that you don't need to do any motor work. The people who would be impressed with a rough idle would be of little help in assisting you in your quest for more power and the people who would help you in your quest for more power would not be impressed by a rough idle. Here's hoping you learn that trying to impress yourself or others with the lope of a motor, when it's actually a pig (327 with production heads), is an exercise in vanity that will earn you nothing but disrespect from those who know better.
 
#6 ·
The rv cam is likely the the ballpark of a correct cam choice for that combination. If you want more lope go with a custom cam with similar intake duration (214ish) and a bunch of exhaust duration (230ish) on a narrow lsa (like a mini-thumper cam). You'll lose a little low end power but you'll gain a little up top and get the sound you're after.
 
#9 ·
pop both valve covers off and get the casting #s off the heads. you might have 2 different heads. use a tachometer, gps with speed, and tire size to figure out what gear you are runnin. that 327 likes to rev a lil higher then the 350. if you don't know the deck height, you might wanna pull the heads and measure it, before throwing money on parts that you might not need. you might have the right cam, just needs to be degreed in, instead of thrown in. a 9.5:1 iron headed 327 with the 268h cam, edlebrock rpm performer, holley 3310 750, should pull hard from 2000-5800. good luck, rick
 
#12 ·
331 CI, pump-friendly 9.5:1 CR
K&N 14"x4" air filter, Corvette drop base and lid
Holley 600 dp, choke horn milled and blended, Primary - 69, Secondary – 74, Squirters - 21
1/2" Aluminum open spacer port matched to manifold, exterior polished
Edelbrock Performer RPM intake manifold, port matched, exterior polished with all extraneous castings and lettering removed
Homemade lifter valley splash shield to keep hot oil off manifold bottom
Manifold heat riser crossover blocked
Camel hump 1.94/1.50 heads hogged out to 2.02/1.60, pocket ported, port matched, pump-friendly hardened seats, 3-angle valve job
Cylinder bores clearanced to unshroud the valves
Comp Cams 1.52:1 roller-tip rockers
Crane Cam Vintage Muscle 327/350 hp cam, 222 degrees @ 0.05, 0.447" lift (with 1.50 rockers)
Doug Thorley headers, dechromed and ceramic-coated
2.5" mandral-bent exhaust (including tips), 2" cross-over just before rear axle
DynoMax stainless Ultra Flow mufflers
Millerspeed 1-1/2” Gilmer under drive belt drive system
Mallory Hyfire IV CD ignition box triggered off Accel points
Mallory high voltage chrome coil
Mallory spiral-wound coil wire
Mallory solid copper plug wires, ends soldered to wires
Champion plugs
37 degrees total ignition advance
Carter high volume fuel pump
Melling high volume oil pump
Open breathers
Polished aluminum high flow water pump
160-degree thermostat
Flex fan with polished aluminum spacer
Polished aluminum one-wire 100 amp alternator
Header Power Bracket
Keisler TKO600 5-Speed
Hurst shifter
3.70:1 positraction with Big Block yokes
225/60/15 Firestone Firehawk SZ50s on 7”-wide Western 30-spoke wheels
 
#14 · (Edited)
I have a 1962 Chevrolet Bel Air, Surf Green, 2-door sedan which was factory equipped with a 327 cu.in. / 300 HP engine, 4-speed and 3.70 P-case positraction. The 327 engine was rebuilt about ten years ago, which is 9 years before I aquired the car. I was told a Summuit K1105 camshaft was used and stock Z-28 valve springs set up with 110 lb. seat / 305 open pressure. . My Bel Air is equipped with the original 1962 double hump "462" 300 HP heads with Speed Pro flat top forged pistons. My '62 Bel Air has a stock dual exhaust system and the original 2-1/2" outlet ram's horn exhaust manifods. Also during the rebuild, the original 1962 Carter AFB (650 CFM at WOT) and stock cast iron intake manifold was replaced with a 1967 Rochester Q-jet (800 CFM at WOT) and stock cast iron intake manifold. Original oil fill tube and no PCV system.

The Summit K1105 hydaulic camshaft really comes on in 2nd gear from 3000 to 4800 RPM. The Summit K1105 camshaft is designed for today's gasolines and an engine with as little as 9.5:1 compression ratio. The Chevrolet L79 camshaft is perhaps the best small block hydraulic lifter camshaft produced by GM but it needs no less than 11:1 compression ratio to work or the low end grunt would be sacrificed. The L79 (or 151) camshaft has been discontinued by GM. The L79 camshaft was a single pattern camshaft and was used in Corvettes with a 327 cu. in. / 350 HP engines with 11:1 compression ratio. In 1966, my associate purchased a Chevy II with the L79 engine option and 4-speed transmission, a very rare combination, and it was excellent engine to use in a light weight car. The L79 camshaft has .447" valve lift and 221 deg. duration and an engine with that camshaft needed no less than 105 octane premium gasoline.

The Summit K1105 camshaft has 224 deg. dur., .460 " lift (I), 487" lift (E), 224 deg. duration (I-E) with a 114 LSA. It is a dual pattern camshaft for a stock exhaust system and can use 9.5:1 to 10:1 compression ratio. It is excellent to use on the street in a heavy car and a manual transmission with 97 octane gasoline, which describes most street driven cars today. .
 
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