Cliff's Quadrajet Parts and Rebuild Kits
General Category => Quadrajet Carb Talk and Tips => Topic started by: Brent88mc on February 24, 2020, 01:27:27 PM
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So I've been lurking for a while and finally registered today. I have a all stock 88 monte carlo ss with factory 305. I've been doing some figuring on a 383 but I'm worried about my cam spec because I want to retain my ccc system as I find it to be pretty neat. I'm wanting to get in the 400 h.p. 400 ft/lbs range. The car is only a weekend car. I'm just wanting a little red light to red light power. A cruiser with good street manners. Engine specs are .30 bore, 4 bolt, 1 piece seal gm block. I'm wanting to just run pump gas. So I was thinking 9.1 compression. .000 deck, .040 gasket, 24cc dished pistons. 5.7 length rod. Go with vortec heads 64cc, get machined for higher lift and better valve springs. I've been looking at the gm " hot" roller cam 218I/228E @ .050, lift .560/.560, 112 Lsa, with 1.6:1 roller rockers. How will the ccc handle this combination? Also what changes need to be made to the quadrajet. Any opinions would greatly be appreciated. Also if you have any better options that you know of it would be appreciated.
THANKS
Brent
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Actually I put the cam specs in wrong. What do you think of the gm hot cam with 1.5:1 roller rockers. 218/228@.050, lift .492/.492, 112 lsa. If you use 1.6:1 the lift is .525/.525 Or is there a better cam choice?
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Don't be afraid of compression, it is your friend with these things, especially making power.
More compression allows for larger cams with less negatives. In other words smoother idle, more vacuum, and more power at every RPM.
With Vortec (or any other "modern" head with a decent combustion chamber and tight quench) you can EASILY run higher compression on pump gas with zero issues.
Matter of fact lowering compression with a lot of quench and thick head gaskets, etc increases octane requirements all else being equal. The engine done in that fashion will also put more heat in the coolant, and take more timing and fuel to make best power.
That cam is excellent in a 355 build and not too bad in a 383. I'm not a big fan of the 383's but have done scores of 355's and that is my "go-to" cam when using a later block machine for roller cam hardware. I've also done a good many with older blocks and flat cams. My favorite there is the Speed Pro CS-179R with 1.6 rockers on it. It's basically a 327/350hp clone. In a 355 build with flat tops, good flowing 64cc heads and super-tight quench it will tear your head off to at least 6000rpm's.
The key to success with a CCC carb and all the trimmings is decent vacuum production at idle speed. Higher compression and wider LSA are your friends with that sort of thing.
I'm not overly fond of the later Vortec heads. Plenty of potential there but there are paper thin and by the time you machine them for screw in studs, guide plates and better springs/hardware you could have bought better heads, plus they require a special intake and no heat crossovers possible......Cliff
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I'm just wanting a red light to red light fun car. So you think a good setup would be a 355, flat top pistons. .000 deck, gm hot cam. With a .040 gasket and 64cc heads that would put you around 10.48 compression. Still good on pump gas? On the 355 with the hot cam would you go 1.6 or 1.5 rocker ratio? With this setup what heads would you suggest? Also what changes would need to be done to the cc carb for this application?
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The carb really woln't need a lot of help, other than good parts, high flow N/S assembly, HP accl pump, smaller secondary rods, grinding the secondary airflap stop a bit, and quick-release pull-off.
I would go no more than .040" quench, which means zero decking the block and Felpro .039" gasket. Tight quench is your friend with these engines, especially the SBC. With a "modern" combustion chamber and .035-.040" quench you can easily manage mid 10's or a little higher for compression with the right cam. You could also go .015-.018" in the holes at TDC and a .020" gasket, for example.
Just stay as far away as you can from "fast ramp"/short seat timing grinds. The factory GM roller cam is excellent for what you are doing and I wouldn't hesitate to use it in a 355 build with some compression in it. Use the high ratio rockers as well which will add some effective duration and lower dynamic cylinder pressure a bit.
I did a 355 about 15 years ago with 64cc heads and that cam, 10.6 to 1 compression. The customer who hired me came up here with magazine articles about using lowering compression (for pump gas) and using some fast ramp-whiz bang Comp cam. We went super tight quench and the GM roller instead.
So he installs the engine, or pays to have it done, then comes "limping" up the driveway a few days later bellyaching about it being down on power and running "rough". Turns out two plug wires were off and hanging under the car!
We hooked up the plug wires, set the timing, and off for a test drive he goes. He's gone much longer than expected, then comes walking back to the shop about half hour later. Turns out he got about a mile away and hit the throttle hard, found traction and threw the driveshaft out from under the car and over into the ditch!
That engine still lives fine today and zero issues anyplace on pump 91-93 octane pump gas. It makes more power than the vehicle could ever use (1987 Monte Carlo SS), and gets over 20mpg's for "normal" driving........Cliff
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Thank you for your guidance. What heads would you recommend? Also how does the factory distributor gear work with that cam. It says it needs a melonized gear?
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The factory roller cams are cast steel so only require the melonized gear. A plastic or bronze gear isn't needed on them.....