i have a 72 chevelle with a 327 w/ mostly stock lower end, flat pistons trickflow 64cc heads, 228 234 duration-480 494 lift. befor i installed this cam i had a 234 234 488 488 cam which had instant response when you mashed the throttle to the floor even from low idle even with a whiped cam lobe, seems like that cam had, by far, the best performance for my set-up. with this new grind i seem to have a slight skip or delay in throttle response, no backfire or anything, just a bogging when you are quick with the throttle. i never touched any carb settings for break-in, i find after doing open heart surgery to your engine the less you mess with the better. i have tried some different timing and carb settings since but to no avail. for cruizin you would never know anything was wrong, but if you were to try quarter mile with this thing I'm sure my et's would be weak because of the lag i have. i have a noticable difference in idle and vacuum with this cam although the numbers are relatively close. the new cam is supposed to have a broader power band but right now it seems the older cam was better. is this just a caracteristic of this cam or should i be looking for something wrong!
hydrolic lifters, crane cam, all roller rockers adjusted 1/2 turn in for lifter preload, about 300 miles on cam right now.

Imho, both cams are too big!

You should be down around 9.5 to maybe 9.75 to 1 CR. so a good old CC 268HE or Crane/Cam Dynamics 272/272 Energizer will do better for the little motor!

And the new 268 VooDoo is about the largest/most aggressive I would run.

I love these little old short-stroke motors!!

Just make sure you have good valve springs in her!!

And myself, I would run about the same spec. solid lifter cam and rpm her way up top!! Something like a good old CC 270S, the little Crower, an Isky Z-20 and so-on....

pdq67

PS., Oh, my hopped up 300hp/327 had the 272/272 Energizer it it and I'm here ta say that it ran like a "scalded-dog"!!!!!!!!

Did you degree your cam when you installed it? You should be seeing an increase in vacuum with that smaller intake lobe, unless your new cam is from a "lazier" family, or on a tighter LSA.

Often, installing a cam "dot-2-dot" doesn't put it where it needs to be. Variations in timing gears and cam cores can cause this.

Quick check: Roll the engine over to TDC during overlap(both valves slightly open). Measure the distance from the bottom of the spring to the top of the retainer. The exhaust should show 0.030-0.050 less if the cam is advanced enough.

A retarded cam will murder bottom-end performance, and run just fine up top.

Are you running enough initial timing?

You need at least 18 deg initial with that cam in a 327,that's a lrg cam for a 327.

Watch total doesnt go over 38 when adv initial to 18.

With that much cam in a 327 you may need to go to 20 deg initial so keep that in mind.

Scott

definately runs better with timing advanced more, as long as i am above 2200 rpms or so i have no skip or delay, better vacuum too! thanx for your help on that!
now if i could only get the rockers quiet! i have absolutely no insulation in this thing between me and the motor so i hear everything! maybe thats my problem! QUESTION, will lifters continue to quiet down after some miles i wonder? i have a stethiscope so i know which one it is, pulled the intake, pulled apart the lifter, no obvious wear, plunger feels a bit scratchy like it could hang up but i doubt it, reasembled everything, still the loudest rocker/lifter especially when hot.
also have a cold engine knock or klick, goes away after about 3 to 5 minutes of operation over 3000 rpms is worst right before each shift of the auto trans when tickling the throttle. loudest when coasting in a lower gear in higher cruising rpms especially when you back off the throttle a bit and the motor is neither pushing or pulling.
everything about this motor is new trans is bowtie overdrives 2004r noise is still there even after new cam and lifters timing chain & gears new header gaskets and seals though out twice!
maybe i just baby this thing too much maby i will just beat on it and see what happens

removed duplicate posts.

Did you degree your cam when you installed it? You should be seeing an increase in vacuum with that smaller intake lobe, unless your new cam is from a "lazier" family, or on a tighter LSA.

Often, installing a cam "dot-2-dot" doesn't put it where it needs to be. Variations in timing gears and cam cores can cause this.

Quick check: Roll the engine over to TDC during overlap(both valves slightly open). Measure the distance from the bottom of the spring to the top of the retainer. The exhaust should show 0.030-0.050 less if the cam is advanced enough.

A retarded cam will murder bottom-end performance, and run just fine up top.
=
Michael,
Believe that is backwards ;)
The intake will be open more not the exhaust.
The intake lifter will be higher but the retainer to head measurement will be less

But you are correct, putting in a cam without checking timing is not a real good idea,,
I recently sent back about 6 SA Gear adjustable timing sets back.
This was the "good one" with the Torrington bearing,,,,
(they sell to most of the cam companies too)
They were mis-machined by a half tooth or 8 degrees.
First one about drove me nuts for a while trying to figure out WTF was I was doing wrong :D

Good catch, Mike!!!!:p

I left one word out, and it changed the whole meaning, let's just fix that:

The exhaust should show 0.030-0.050 less lift if the cam is advanced enough.

The retainer height should measure more on the exhaust, less on the intake, as Wolfplace stated.

Interested in this thread, as I have a too large cam and very poor idle and low end.

Did you mean to set the base timing at 18 deg, at idle?

This sounds like a lot, will it still start?

I am used to small brand F motors, and no more than 12 ish base timing. Mine is set for spray, so I don't usually have more than 8-9 deg base in it, max, with a total of 34 or so. Mech only, no vac on that motor.

I tried 10 deg base on my Chevelle, and it was better than 6-8, but still idles poorly.

I never thought about going to 14-18 deg?

Ron,Yes 16-18 deg initial at idle is a very common initial timing setting to use with a perf cam in a sbc or bbc along with approx 20 deg mech in dist for a 36-38 total.

The 8-10 deg you have been running is way too retartded with a perf cam,your wasting fuel,loosing a lot of power ,and the motor will run hotter to with the initialtiming 6-8 deg retarded.

If you have a hi trq starter in good cond with a heat shield,a good battery (minimum 750-800 cca) & an alt with a min of approx 55-61 amp it should start ok when hot. But if you have 1 or more weak componants in your starting system like a weak battery etc then you may have hot start issues.

Scott

i actually have that exact issue with hot starting, especially because i am still runing my origional 35 year old 307 starter, and a 43 dollar wallmart battery that sat uncharged for the winter! and i'm lucky if my alt is 43 amps and i get the ole tut-rutt-rutt-rutt-varuuuum! you got your fingers crossed the whole time because it sounds like the starter won't make one more rotation of the motor, all your lights are dimming out! thats right where you want your timing! i'm sure if i spent a little money on a fresh starter and battery i wouldn't be crossing my fingers! i thought it would be more fun to kill my 35 year old starter first!http://www.chevelles.com/forums/images/icons/icon10.gif

Derek,get a fresh hi torque starter with the h/d hi temp solenoid & h/d solenoid spring,starter heat shield,an alt with a min of 55 amps(best 61-63 amp) all were stock from gm & readily available ,a battery with a min of 750 CCA not CC(Interstate Megatron is a great battery if you arent into the original appearance battery),and also check & clean all the starting system connections and body to motor & motor to frame grounds while your at it,replace any old/questionable grounds/wires,esp when it comes to the main battery poss & neg cables.

Yes this will cost you approx $300-$325 to do but then you shouldnt have any more hot start issues for many yrs to come.

Scott