Hey guys,

I'm posting this for my brother,... I do all the performance mods on his car anyway. I myself have a 396 Chevelle that launches pretty good. He just purchased a 327 Nova, and although I'm more of a big block guy myself, I know that the 350's and 327's can make some pretty good power. I had a 350 85 Monte that moved. Anyway, he has been complaining that the car is running a little slow. I took it for a ride and I could tell that it was lacking power. Here's the combination.... Its a newly rebuilt 327 with an edelbrock intake manifold and holley carb. Its very slightly cam'd,... seems like a normal car. Its got many of the bolt on's -- headers and such; and an MSD Ignition with a Mallory Distributor. O, did I mention FULIE heads. Anyway, when I nail it, the car seems to bog just a little and then accelerates slowly off the line. As it approaches 3500-4000 RPM it finally begins to move. Worst of all,... which I think is bothering us both most, is that it won't do a burn out on dry ground. (Right of passage) It currently has 3.90 gears and a TH-350 --- although we are changing the trans to a 700R4. Anyway,... Whats a good combination of performance mods that will really boost the power and torque for about $1000 or less. Thanks for the imput,
Dan

What is the initial ignition timing set at?

What type of Holley? CFM rating, vacuum or mechanical(double pumper) secondaries?

This would be a good place to start, to make sure you don't have enough still left in the tune. Even my bone-stock 350 with bolt-ons gained a half second in the 1/8th mile from carb and ignition tuning.

It sounds like you've got a problem with that bog. There might be quite a bit of HP on the table if you tune it right.

If the tune is good, you have quite a bit of options.

1. nitrous
2. What compression ratio is it at now? You might be able to get some more compression from swapping head gaskets.
3. Cam swap. but this depends on what you CR is, so you might do this and the head gasket swap at once.
4. Torque convertor swap, would let the engine rev up into its range faster.

sounds to me like the engine isnt running right, that car should have no problem spinning the tires.

what size holley carb? which edelbrock intake?

which mallory distributor? whats the initial and total advance curently set at?

when was the last time the plugs, wires, cap and rotor were changed?

*edit* whoops, look like Enrique beat me to it

Brandon, you hit on a point I missed though. Last week I changed the plug wires and plugs and my engine became much more responsive. Maybe I'll take it out on Thursday and see if it added any HP.

Enrique

yep, ive been down this road as well, had a lack of power in my chevelle. come to find out a plug wire was bad even though it looked good, its amazing how much better these things run on all eight cyls :D .

Sounds like a perfect description of what a car with a "151" cam does.... that's the supposedly "375 HP 327" cam. What a pile of dung. Using any sort of "ratings" method that involves actually building a motor and measuring its output, that cam will protect the motor from ever producing more than about 275 HP, even if everything else about the motor is optimized.

That cam has 221° of .050" duration on both intake and exhaust, with .447" of lift on both. Seems like it usually claims about 290° of "advertised" duration, but that number varies widely from one mfr to another due to differences in measurement methods. It's a very common cam to find "blueprint" aftermarket versions of, for some reason. I think people who aren't familiar with it, fall for that "375 HP" BS.

As was said, make sure there's nothing defective about it; ignition system working well, carb jetting within reason, etc. Same as you'd do with any car you just bought, no matter how well or poorly it seems to run whenever you take posession of it. But prepare yourself mentally for a cam swap.

A good cam to go with would be a Comp XE262; or a cam of similar design with similar numbers from Crane, Comp, Lunati, Crower, etc. Look for something in the 215°-220° intake duration, 8-10° more exhaust duration than intake, the shortest possible "advertised" duration (262 in the case of the Comp, 272 for the Crane that's somewhat equivalent), and as much lift as possible (should be around .470").

If it has stock rubber rockers, better ones that don't flex, will be a BIG help.

If the intake is the Performer, replace it with a Performer RPM.

The carb needs to be around 650 CFM. If it has a bigger one than that, consider replacing it with a Holley or Demon 650, and selling whatever is on it.

Sounds like a perfect description of what a car with a "151" cam does.... An "expert" talked us into using one of those cams in a flat-top, "camel back" head-equipped 327 back when I didn't know any better. We had the engine in a '63 Impala with a PG and 3.55 gears. To say it was a slug down low would be an understatement. Ran OK from about 3500-4000 but was done at 5000. Major disappointment.

RBs cam advice is good, but start with the basics... tune-up, compression check, etc.

Chances are the carb on that 327 is too large and/or it needs a good overall tune up including properly curving the distributor. I'm also going to guess the carb has mechanical secondaries which would contribute to the bog you are experiencing.

The carb would be more effective at 600 cfm with vacuum secondaries. Try to find out what cam it has as it may not be optimized to the rest of the engine build.

OK, an about 10 to 1 CR., 327 motor, onna the old 250/275/300 hp core motors with four valve notch flat-tops and medium sized valve 64 cc d/h heads with no more then a good old CC 268HE or a Crane/Cam Dynamics 272/272 Energizer hy-cam and a 600 holley and high-rise and a set of cheap 1.625" four tube, long headers WILL run like a "scalded-dog"!!!

AND that old -151 cam may not be the best nowadays but up it's CR. to 11 to 1 AND it will run like it should!! I ran the old -151 in my stock original about 10 to 1 CR., L-48 350 motor and it ran FINE, imho!!

I will just about bet you have a 210hp/327 core motor that somebody has sold you as a hopped up 327 which it is but since it is so low compressioned, it won't hardly get out of it's own way!!

Post back the letters at the end of the VIN string on the pad above the pass. side water pump's upper bolt and pull a valve cover and also post the head casting number and we will at least know a little bit more about what you MAY have if it is still pretty much a stock long block..

pdq67

I'll second the motion about using a "151"
cam in a motor with decent compression and
set up correctly. Matter of fact, some of
my best running motors had 283 powerpacks
on them. These little boogers with some
mild porting with a decent 3 angle valve
job would haul the mail. You would be
surprised the weird combo's we used to
run and run well with graemlins/thumbsup.gif

In the late 60's and through the mid 70's
I used them alot. I had a ball beating up
some BB's

It's all in the tuning graemlins/thumbsup.gif

Novadude,

You say your "151" cam signed off at 5000 ?

Thats funny because I would shift some of
my 151 cammed motors at 6800. I used anti-
pumps and big heads with factory Z-28
intakes or the old style torker.

Matter of fact, back then, the only cam I
liked better was a Manley thunderstick.
This was a solid grind 325/335 525-535
lift.

Sounds to me like you had a case of point
float or weak valve springs. You know
over the years cam design has gone to shorter
duration and higher lifts. In the course
of this cam design evolution, there have
been so many valvetrain failures that one
has to wonder if the high lift theory
is the most reliable. Power wise, there
is an improvement but at the cost of
valvetrain longevity.

Just my 2cents.

danspeed1, whats the history of the tranny? with what you describe i would go with the fact that the converter has ruined itself. had a olds cutlass that went bad and you could floor it and it wouldn't get out of it's own way. it was like a manual taking off in third gear. we replaced it and once again it would light the tires up from a standing start. that's if you sure all else is good.

If the engine is fresh and you don't know what the specs are then start with a compression test to verify the cam selected is runable with the static compression ratio. Look for 150psi at a minimum with 170ish being optimum. If all is well with the compression test then start tuning. Timing curve, idle circuit, main jet, power valve and accelerator pump shot. With 3.90 gears and the light weight of the Nova I would think frying the tires through first gear should be easy if the engine combo is close to right. jmo, Bob

Thanks for the advice guys,...

I'll start by calling Edelbrock tomorrow and ordering either a 600 or a 650 CFM carb depending on what they offers. I agree,... I told my brother I thought the 750 was way too big for a 327 of his build. It must be drowning. Anyway,... next I'm going to give the new spark plugs and a set of wires a try. I think the cam in the car is one of those factory rebuilds --- its most likely out of an overhaul kit for a 327,... the build is sweet, but it seems really stock minus the heads. I'm looking into a 700R4 with a 2500 or 3000 stall converter. I hope thats not too high. After we do all that, ill ask for some more advice on proper camming for the engine... that is,... if theres still not enough power (theres never enough power!). Anyway,... Anymore good suggestions are gladly welcomed. Ill see if I can give you a better Idea of what the car has (to my knowledge) in a list)

Stock Air Cleaner
Currently 750 CFM Holley (soon to be Edelbrock 600 or 650)
Mallory Distributor with mechanical advance
MSD Ignition 6A
Edelbrock Performer Intake Manifold
Fuelie Heads (If i remember correctly 9.5 to 1 compresssion)
New but stock bottom end
NEW TH-350 Trans (Soon to be 700R4 with 2500 - 3000 Stall)
3.90 Gears in the rear
General Tires (14 Inch rims - stock)
No name Headers
Stock OEM Mufflers (Soon to be Dynomax Bullet)

Hope that helps,... thanks

Dan

http://us.f1.yahoofs.com/users/a5065544/d632/__sr_/2f6e.jpg?phbzXpBBWG3s9Avi http://us.f1.yahoofs.com/users/a5065544/d632/__sr_/5504.jpg?phbzXpBB39n7VUPG http://us.f1.yahoofs.com/users/a5065544/d632/__sr_/3d0e.jpg?phbzXpBB80JgZ5Qj

You need to figure out what your timing is set at.

You're going to want 12-18* of advance at Idle with the vacuum advance unhooked and the carb port plugged, assuming you have vacuum advance, which you should with this combo.

Originally posted by Slowpoke70:
You need to figure out what your timing is set at.

You're going to want 12-18* of advance at Idle with the vacuum advance unhooked and the carb port plugged, assuming you have vacuum advance, which you should with this combo. Nope,... Its acutally got a Mallory with an NON-Vacuum Advance -- Everthing on the carb is plugged.
Dan

Dan

is that a Mallory Unilite distributor?

Originally posted by RatONaStick:
Dan

is that a Mallory Unilite distributor? Yes,.... It is! smile.gif

Dan

Either way, it seems like the intial timing is unknown? My car runs the way it did with my old 305 if I have anything less than 10* and it runs the best with 18* but 16* is the most consistant so far. Anything above 18 and it runs inconsistant.

Timing is BIG factor on how it runs.

I think some of you are missing RBs point with the 151 cam.

It may very well have worked for you back in the 60's, but as far as cam technology has come since then..... Seems like a waste to run a cam from back when you needed 11 to 1 and leaded fuel, compared to 9 to 1 and 87 with a Vortec headed motor today for example.

Originally posted by Slowpoke70:
Either way, it seems like the intial timing is unknown? My car runs the way it did with my old 305 if I have anything less than 10* and it runs the best with 18* but 16* is the most consistant so far. Anything above 18 and it runs inconsistant.

Timing is BIG factor on how it runs. Your saying to run 16* with a 305? i have a 305 with a glide and 308's, and it runs like the 327 that Dan is talking about.
it wont burnout in the dry, and it can hardly get out of its own way. but i think its has to do with the 1.76 1st and the 10" wide tires in the rear.

keep the coments coming, i want to hear more. hehe
smile.gif
aaron

Your first step should be getting a carb on there that makes a little more sense on top of the motor. Sounds like you plan on doing that, so stepping up(or actually stepping down) to the eddy 600cfm carb will be enough carb for this motor to make its horsepower, but the smaller venturis will bump up air velocity and itll kick a little better. After the carb change, then go throughout everything and work hard on the tuneup. Before you even think of a converter swap, try to get a more solid estimate of cam specs and comrpession if you are keeping that as is. From your comment about a slight cam, a 3000 converter might be a bit much cause there might be enough torque coming in lower than 3000rpm that you will want to make use of it. Than again, it might be a good bet.

Its Thanksgiving today,... Happy Thanksgiving everyone, but tomorrow I will give edelbrock a call about the carb and make the purchase. After I tune it a little better and maybe change the plugs and wires we will discuss a cam change. Theres no reason to have a cam that light when these days they make so many more streetable cams that are high performance.
Have a good thanksgiving,

Dan

Dan

im using a mallory unilite as well, my distributor only has 20 degrees of mechanical advance built in from the factory. what this means is, i have to set the initial timing at 16 degrees initial to get 36 degrees total advance, 16+20=36.

you should shoot for 34-38 degrees total advance, so Enrique's suggestion of 12-18 initial is right on. that is as long as the distributor wasnt played with (they are adjustable).

the first thing i would do is set the timing to 14-16 degrees initial and take the car for a ride, its free unless you dont have a timing light.

on the carb, i know everyone says a 750 is too big, and if its a double pumper thats the truth. BUT if thats a 750 vacuum secondary that carb can be tuned to work fine on that car. especially considering the car is a light nova with plenty of gear, has a dual plane intake and will eventually have a higher stall converter.

so what is the carb exactly? vacuum secondary or double pumper?

how about the list number off of the front of the choke horn on the carb?

No MY FYN 79, you seem to missing the boat here b/c you are comparing "apples to oranges" here with respect to an old cam and a new cam!!

Take a true 11.5 to 1 motor and install a good old 30-30 solid cam in it and then pull it and install a good old CC 270S solid in it and see which runs the best up top?? I bet it's the good old 30-30 solid cam!!

Now take the same motor and make it say, 9.75 to 1 CR., and then run both cams AND I bet the 270S cam wins!!

I have said many times that lift is a secondary power producer vs duration as Johnny is pointing out above with respect to high lift cams needing strong springs AND cam flat-spotting lobe wear!!

Same thing with stock Vortec low lift heads but just install set of cheap Z- (-142) springs on them AND run a lift limited roundy-round cam of the spec's of your choice so that you don't have to spend money making them accept high lifts!!

pdq67

Ps., onna the sweetest little solid cams that has ever been made for maller motors like a good 327 and down, is the great old-fashioned Little Duntov, -097 cam. But a check of it's spec's show's that it is of a modern, tight-lash design so go figure!!!

And it was used in the 360hp/327 FI motor before the 30-30 cammed 375hp/327FI motor came out!! About .390" lift vs about .455" lift so go figure??

Originally posted by pdq67:
No MY FYN 79, you seem to missing the boat here b/c you are comparing "apples to oranges" here with respect to an old cam and a new cam!!

Take a true 11.5 to 1 motor and install a good old 30-30 solid cam in it and then pull it and install a good old CC 270S solid in it and see which runs the best up top?? I bet it's the good old 30-30 solid cam!!

Now take the same motor and make it say, 9.75 to 1 CR., and then run both cams AND I bet the 270S cam wins!!

I have said many times that lift is a secondary power producer vs duration as Johnny is pointing out above with respect to high lift cams needing strong springs AND cam flat-spotting lobe wear!!

Same thing with stock Vortec low lift heads but just install set of cheap Z- (-142) springs on them AND run a lift limited roundy-round cam of the spec's of your choice so that you don't have to spend money making them accept high lifts!!

pdq67

Ps., onna the sweetest little solid cams that has ever been made for maller motors like a good 327 and down, is the great old-fashioned Little Duntov, -097 cam. But a check of it's spec's show's that it is of a modern, tight-lash design so go figure!!!

And it was used in the 360hp/327 FI motor before the 30-30 cammed 375hp/327FI motor came out!! About .390" lift vs about .455" lift so go figure?? I dont disagree with you at all PD, but in regards to the original post...

So he should run 11.5 to 1 with iron heads to make your old cam come alive for his street motor?
I'm confused why you had a problem with what I said. For his typical compression street motor, a newer design cam like an XE-series Comp sounds like the hot ticket to me...

More aggressive?... Yes
More efficient for a street motor?.... Yes also.

Well fellas I guess my age is showing :rolleyes:

I am old school and firmly believe in the
more duration and moderate lift theory.
We had such great results with all the old
cam grinds that were available to us.

Heck, we shifted high, used many oddball
heads, and had VERY few valvetrain related
problems. As PDQ pointed out, the Duntov
097 worked great as did the 151. The only
GM solid I used and did not care for was
the 140. This was lazy on the bottom and
needed alot of gear.

All of these cams on any given smallblock
that was properly tuned was capable of 11's
and low 12's. We drove these cars on the
street and raced every conceivable musclecar
that Detroit made. I'll say this much - even
my 440 six-pack cars would get their feelings
hurt when my Brother would drive my Nova.

The Nova was a 331, 140 cam, lashed at 24-26,
with a set of hookers and Tarantula intake
with a 3310 Holley. Now I will admit that
the "Deuce" has 410's and my Mopars had 391's
but the little "giant killer" still had
more after 100mph.

One more short but true story. My Buddy just
out of the Army decided to buy a new LS6.
Naturally he had to pick on me. At the time
I had a 62Deuce with a 327, 151 cam, and 2
AFB's stuck on a old Edelbrock intake.
Funny thing was that I had iron vette exhaust
manifolds bolted to a pair of stock 283
power pack heads. Seems like a tame combo
right? Well when we went (all speeds)
we looked at each other the whole way. He
had 456's and I had a 370 gear.

I shifter my car at 7800 and never, ever
had a valvetrain problem. Actually, the only
valetrain problems I ever had were with my
Pontiacs.

I wish the cam manufacturers would go back
to long duration grinds so we could keep the
top end of our motors in good shape.

Love the old stories, Johnny! smile.gif

Regarding my "151" cam application signing off at 5000 rpm....

I left out some key info about the combo...

This was a 250hp/327 in a resto, using the stock Rochester 4GC and 2" rams horn manifolds. I suspect the induction / exhaust is what caused the big power drop on that particular combo.

Nevertheless, I still contend that the "151" cam is a poor choice for low compression engines. It seemed REALLY flat down low in a ~9.5:1 327.

Hi novadude,

Gotta agree with your comment about using
the 151 cam with low compression. Funny,
because that is still true today. Look
at Edelbrocks Performer cam. It is real
soggy on the bottom unless your are running
decent compression.

I guess the biggest difference today is
that there are so many aftermarket performance
goodies being offered, that it's hard to make
a choice. You hear so much pro and con that
it's a gamble to decide what set-up is
best.

Back in the day, we used what was available
and used our imagination and did the best
with what we had. smile.gif

Ok.... Going to give Edelbrock a call tomorrow and order the Carb and an Performer RPM Airgap Mainfold. We checked our funds and are ready to go on the cam!!,... now all I need Is some advice....

Please check the Performance section of the Chevelle Tech Forum for my cam forum.

Dan

Danspeed,

This past summer, my Daughter and I built
a V-8 S-10. It had a 350 and we decided to
put a Dart air gap on it along with a 750
VS Holley. The truck had 4.10's with shorty
headers. It ran great but I wound up pulling the 750 Holley to use on another motor. I
replaced it with a temporary 750 Edelbrock.
I'll say this much - The Edelbrock was nice,
but it's not a Holley. There was a noticable difference in performance between the two.

I know that it's "to each his own" but
my experience with many, many of each carb
has me favoring the good ole 600-750 Holley.

It's the old high compressioned, old school long duration, low lift cam tests against modern shorter duration, high lift cam test in a low to medium CR. motor!!

NOT apples to apples by an stretch!!

Test each cam on a quarter mile strip in the same motor and car combination with gearing and tires at say 3.73's or maybe even 4.10's and 26" tall except make each motor's ECR equal at 8!! AND then see who wins!! Old school!! IMHO!!

And an M-20, posi, '66 Duece would be the car to use!!

pdq67

graemlins/thumbsup.gif