67 Camaro Mild 327 engine build help!!

[Mayhem Matt]

I have a fresh built 327 small block in my 67 Camaro and need a little advanced help from people with good engine and carb knowledge...

Here are the specs on the 327 build....

10:5:1 Compression running 91 octane
Factory forged steel bottom end (Crank and Rods)
.020 under on the crank
bored .030 over
3.25 on the stroke
11:1 forged dome top pistons
2.7 dome cc
Gap to fit Molly rings
.016 on the deck clearance
.039 felpro head gaskets
So .055 total deck clearance
High volume oil pump
Comp cams flat tappet hydraulic 292h cam
Cam specs http://www.compcams.com/Company/CC/c...x?csid=81&sb=2
64cc camel hump heads with 5 angle valve job
1.94int 1.6 exh SS valves
1.5 ratio full aluminum roller rockers
High rise dual plane intake manifold
Holley 670 street avenger dual feed carb
Holley high volume fuel pump
HEI billet distributor
MSD plug wires
Accel racing plugs gapped at .45
Electric fan
Electric water pump
1 3/4 long tube headman headers
2.5" H Pipe dual exhaust
40 series Flowmasters
Every bolt in and on the engine is ARP and torqued to spec
Cam is broke in proper with 20mins at 2000rpms and 10mins changing RPMs between 1800 and 2300
Initial timing set at 12 degrees and timing is around 36 degrees with vacuum adv plugged in at 3000rpms
I'm running a Borg Warner World Class 5-speed manual trans and a 12 bolt differential with 4:10 gears

My question/problem being, is my carb to small for this build? Ive adjusted the hell out of my timing and this 670 carb and it is a pain to get it to idle cold and by itself. When it gets to temp it will run fine at 1000 rpms and pull 10 psi of vacuum which is good for this cam. If I turn the car off then back on I have to sometimes hold the throttle to the ground to get it to start then it will idle normal again. It also doesn't have the crisp throttle an engine like this should have when I rev it. When driving it doesn't quite have that spunk I expected it to have. There's no hesitation when driving so I don't know where my problem is...

[Mr Twisty]

It's actually a bit on the large side, how do the plugs look? Rich?

[willhe64]

Does this carb have a choke? Electric or Manual choke?
Very big cam too. Large overlap and not much displacement to make vacuum.

[willhe64]

Second read of the cam specs. Way too much cam. Street/strip my ass. 110 degree lobe separation and 292 duration is too much, especially for a 327. Had a cam like this in a 350 drag engine, wouldn't idle below 1300 and ran a 5500 stall convertor.

[RatRacer]

Wow, old school hella-cam.
I ran one back in the mid 80's in my 66 Chevy II 327, for 2 months before I scrapped it for a milder 268H. This was a bottom end dog, no matter what I threw at it for streetable gears or stalls.
Bleed down lifters helped alot, cutting down the low rpm lift and improved vaccuum.
Try moving up your initial timing, around to the 16° area.

[Stingr69]

Needs smaller cam - Needs more ignition advance at idle to try to make up for huge cam. Careful carb setup would help. It is not about carb SIZE as much as it is the throttle stop setting/main jetting/float setting/acellerator pump setting/manifold vacuum at idle hooked up to the advance can (and fully deployed) that will help.

Gap the plugs at .035". Big gaps are needed for lean, emissions-type mixtures. You do not need that big of a gap. Not going to fix anything but might help.

-Mark.

[Southern Comfort]

I'm no expert, but..
1) 670 cfm shouldn't cause these issues. Bad carb setup maybe.
2) cam spec says "Very Rough Idle". That says to me it's gonna stall easily and needs 3500 rpm to smooth out.
3) need to verify you have functional Vacuum Advance timing. This will turn any street motor in to a dog if not setup properly.

So before swapping carbs or cams I would go over the vacuum advance setup.

[Mayhem Matt]

Thanks guys for the input I've been reading on this cam being a bit too big. The carb seem tuned to the best I can get it all my engine math says a 670 should be fine. This carb is also a vacuum secondary if that changes anything.

I'm gunna try to curve the distributor with some lighter springs and see if that helps. I've also read about the bleed down lifters too but if I go that route I mine as well change the cam. I also might have to change my vacuum can on the distributor to accept a lower vacuum at idle to stop the eratic idle and the stumble it sometime does when the engine idles also.

If anyone has any other ideas or input please let me know. If not I'm gunna try swapping cam soon.

I want some good off the line power with a nice 2000 to 5500 rpm power curve so please shoot me some good roller cams with some good off line power with that power curve

[Mayhem Matt]

Originally Posted by willhe64

Does this carb have a choke? Electric or Manual choke?
Very big cam too. Large overlap and not much displacement to make vacuum.

It's has an electric choke

[Mayhem Matt]

Originally Posted by Mr Twisty

It's actually a bit on the large side, how do the plugs look? Rich?

Plugs look clean!

[Stingr69]

Crane F-278-2 Solid Lifter cam is worth a look. I have it in my 302 and our engines are very simmilar in spec except you have .25" more stroke. Nice little buzz bomb.

-Mark.

[Southern Comfort]

Your cam may be out of spec or not properly degreed.
It may help to shift the peak rpms down and marginally help low end torque by advancing this cam a few degrees. Double check PTV if you do this.

[willhe64]

Originally Posted by Bumblebee Matt

It's has an electric choke

Verify that it is operating correctly then. You've got too much cam but the hard warm starts could be the choke not releasing all the way when hot.

If you are going roller then get something around 270 duration with more lift. .530 to .550 lift.

[f5journal]

Drill a 1/16" hole in each of the front butterflies. Old School cam, Old school fix