Quadrajet Problem Solving > Dialing in your rebuilt Quadrajet carburetor

Put my rebuilt 17057229 on finally

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Cliff Ruggles:
I get a LOT of complaints about camshafts from folks who contact the shop wanting us to work on their carburetors.

By far and above the Comp XE, Thumper and Mutha-Thumper cams top the list.

I've also had a lot of folks contact us saying they lost lobes on Comp XE camshafts, another reason to stay clear of them. 

Back when those cams first came out the machine shop that I use bought one for an Olds 455 engine they were building.  They do EXCELLENT work and very meticulous engine builders.  It knocked half a dozen lobes off the cam before the engine had 50 miles on it!

I was also good friends with the owner and he assembled the engine.  He had to do the entire rebuild completely over again, costing him a LOT of money and time.  He never went near one of those cams again, and never had any issues since then either....FWIW.....Cliff

Mudsport96:
Unfortunately, I wasn't able to get on the car last night with the daughters school stuff going on. Hopefully tonight I'll get to it.

And yes, I've heard horrible things about the XE line and Thumper line of camshafts, I plan on staying far away from them.
When the engine was done in 1999-2000 I don't think the XE line was out yet, so my uncle went with the High Energy line and the 268 was the biggest. For the few miles it has on it, it has always had fine street manners...minus the spool he wanted. But, now that I bought the car and spent more time with it I've noticed the little things, like the rich idle.
I would love to retrofit the engine to a roller hot cam, because I've read good things about that cam in a carbed application.... But, that's coin I sure don't have.
In the last few months a few of my friends have done rebuilds and I've pointed them away from the tight LSAs that they had been running and they are happier with the idle quality they now have as opposed the the 108 and 106 lsa they had been running.

Cliff Ruggles:
The "HOT" roller cam is one of my favorite camshafts for SBC engine builds.  I also like the Speed Pro CS-179R grind.

It's a nearly duplicate of the original 327/350HP camshaft.  It has long seat timing, up around 290-300, 222 duration @ .050" and .447" lift on a 114LSA.

You will not find a modern cam that will outrun either one of these very easily.  They require high compression, tight squish and both are fine on a steady diet of pump fuel.

My favorite 355 cid SBC combination is to use a flat top piston, zero deck height, stock Felpro .039" blue head gasket, World Products 200cc Sportsman heads, and the CS-179R with  Rhoad V-Max lifters and 1.6 ratio rockers.  With 64cc heads and tight squish they usually come in around mid 10 to 1 for compression.

You will end up with a nice idle quality and plenty of vacuum for power brakes, good street manners, and power well past 6000rpm's.  The power curve (torque) is very broad and flat with plenty of upper mid-range and top end power.

For truck engines we like a little lower compression so will use factory 441, 487, or 993 heads instead and smaller camshaft.  I like the 350/300hp grind.  Another very good choice is the "generic" 214/224/112 grind.  I avoid the smaller "RV" cam at 204/214/112 unless the engine has very low compression like many of the stock 350's did with dished pistons and 76cc combustion chamber heads.

Lots of folks use the inexpensive "Vortec" castings, but I avoid them due to being very thin castings and crack easily, plus they lack the good features of the aftermarket iron heads like screw in studs, guide plates, etc.......Cliff

Mudsport96:
Well, quick update. I haven't done much this week, got hit with mandatory 15 hour days at work. So, needless to say, didn't do anything M-F on the car and yesterday I did a 12 hour shift. So after getting off I put the new vac canister on and hit the key to start the car.... Starter is dead. It spins but doesn't kick the Bendix out to engage the flexplate. So I pulled the starter and grabbed new gear reduction one I had laying around, and went to install it and promptly fell asleep under the car. I guess 102 hour work week wore me out. I'll give another update when I get it running.

77cruiser:
What kind of work do you do? Never fell asleep under a car, but did one time having a root canal breathing the nitrous deeply. ;D

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