383 timing/vaccum/engine combination help

[maddart]

Hi
Just a little history
I had this engine built by a pro stock engine builder. Builder is not very helpful and I can’t count on support.
This build was a slightly more aggressive build than a stock 1967 383.

The following combination of parts were used in the build:
Block machined Bore & torque plate .040 over, Crank clean/check and balance, Closed chamber heads
mill decked with 3 angle valve job. Valve size was increased to 2.14” intake/1.74” exhaust
Ferrea stainless valves were used
KB hypertech 162 pistons with sealed power E233 moly ring set .Stock rods with ARP 145-6002 bolts
Sealed power cam KC661 (Same as Speed pro CS661?) Specs for speed pro= Duration 292 intake/309 exhaust, duration@ .050 214intake/225 exhaust, lift .449 intake/.464 exhaust Lobe C/L is 115.
Sealed power valve springs VS-865 Closed press 109/ open press 323

Comp cam 7948 5/16” pushrods (Listed for ford BB) Mopars not available at the time??

Headers with stock intake and a 750 holley 4160. 4 speed 3:23 gears. 3800# car

I have been trying to get timing down. (Builder said to set at 10 degrees BTDC-This didn’t work to well) With dial back timing light the car seems to run better at the following:

(Current settings)
700RPM 18degrees BTDC
1500RPM 30degrees BTDC
2000RPM 43.5degrees BTDC/60 degrees with vac connected
3000RPM 43.5degrees BTDC

When timed at 12-15 degrees BTDC@ idle the motor runs extremely hot. There is a very noticeable difference in temp under hood when timing. (Also smell un burnt fuel from exhaust)
I just don’t want to damage the motor. Motor seems to want even more advance than the current settings.
Any suggestions on how to improve the timing/vaccum/engine combination would be greatly appreciated
Adjusting carb yields a vacuum of no more than 16 inchs.
I am hoping to change intake to a weiand 8008 dual plane in the next couple of weeks.

 

[Meep-Meep]

I would expect it to run a bit warm being fresh and all. 200 Deg is OK as long as you have good oil in it. The specs seem perfect to me. Not over built. What is the compression? Do a cranking compression test. 15 deg I is not out of the question and that's about what I run my 440 at but it also ran warm when I first got it going.

The 750 might be a little too much carb and it's possible your engine wants a different fuel curve than is being supplied now, especially if the 750 is set up as a race carb from Holley. These don't have a very crisp low speed circuit so you may want to try a 600 - 650 AFB or a Holley that has more of a street calibration to it. A richer mixture will give higher exhaust gas temps. The stock intake is not a big limitation at this point and will probably be just fine in the long run.

 

[rlsbee]

My 383 seems to like between 23-25 initial. I have a Pertronix distributor with the 12 degree limiters installed for 37 total (w/o vacuum). Mine is a street car which has a MP 284/284 cam with 69 degrees overlap. (not the best street cam, I admit) I get about 14" of vacuum. You didn't mention which distributor you're running. Many aftermarket distributors have some method of limiting the total curve. These are usually bushings or stops for the advance weights. A stock distributor can be modified by welding/grinding the slots but it's best done on a distributor machine. Many people will simply set the total at 35-39 degrees and let the initial be where it settles. If the advance springs let you get full centrifugal advance at say 2500 rpm, then set the total there.This is ok if it idles good, doesn't overheat, and doesn't ping. Pinging will mean that you'll need less total. If that doesn't work, set the initial (you may find that you'll need more than 18) and then set the total centfigugal (where it doesn't ping) by limiting total adavance.
Of course, I'm telling ya from my experience and every engine will be different. I really don't think you're too far off, though.

 

[maddart]

The carb is a street vaccum secondary reman from holley. The dist is the one that was on the car-not sure which one it is. I included a photo of the setup.

 

[rlsbee]

That looks like a Mopar Performance distributor and the MP 'orange box' (ECU) mounted on the firewall. I looked up the instructions for setting up that system and I saw no reference to adjusting total centrifugal advance. It does say that initial plus centrifugal should be 38. With the vacuum advance it should be 56 degrees. The springs supplied with that distributor are supposed to bring in total advance by 2000 RPM. That doesn't mean those are the springs on it. They could've been changed.
I've played around with subject a lot on my car. I'm no expert but I've picked up a little info along the way.
I also sent you a PM.

 

[Mebsuta]

My 383 RR: I used camshaft P4452783, which is nearly identical to Speed Pro CS661. Pistons are same compression height as original, and heads are open chamber.

It gets 16 inches of manifold vacuum and smells like a big lawnmower when idling. It always has and did so with the original long block, too. Not sure how many zillions of miles it had on it.

I set it at 10 BTDC. It's been a long time since I have moved it around, but I remember if I went much lower than 5 BTDC, it would backfire. If I advanced too much, it would play castanets and diesel when you shut it off.

It's not the quickest, but it runs pretty good for an old beater. I have Modine 3-row and bypassed heater core. No overheating. When it's together you can fire it up and do errands in it and drive it around until you get tired of putting gas in it.

Rode around in a '71 some years ago and it smelled like a big lawnmower too when it was running. I think that's just how they did.