I'm thinking Edelbrock should recommend a plug for their head. AFR did with mine.

BobE wrote:

I use Champion RC1212YC gaped @0.050".  I've tried gaping @0.055" and found little difference.
I have a 351W, roller block, 0.040" overbore, 9.5 compression, MSD 6AL ignition w/a MSD Distributor, MSD Ignition wires, MSD "Blaster" coil, Edelbrock "Performer" heads, "Performer RPM" intake, Summit mechanical fuel pump, 40 micron filter between pump and carb, Holley 600 CFM DP, 1/2" phenolic spacer between carb & intake, and a Comp Cams Roller XE270HR, #35-351-8 0.512” lift, 270°I - 276°E, Lobe Sep 112°, Int Centerline 108°.
I also have the Shelby scope on my hood, which will allow engine heat to dissipate more quickly than a "non-ventilated" hood.
Hope this helps.

Looks like we have similar builds....except mine is a 302.
I take it you have no HOT Start Issues? 

correct me if Im wrong because Im still learning this, but is the Champion RC1212YC a Colder or Coldest Plug they make for this line?

I guess I need help understanding this main concept, if Im experiencing hot start issues, do i want a Hotter Plug or Colder One to combat it?

Last edited by M1Mustang69 (5/10/2020 9:31 AM)

Keep in Mind People it will Only Start HOT if the pedal is mashed to the floor; WOT, and that doesnt mean it fires right up, just means the battery wont die cranking......

as far as Carburetors go this has to be a BIG indication of what 1, 2 or 3 things could cause it....with my timing at 11 and 43 we know its not that, but perhaps I can play with those numbers up and down to help said potential "1, 2 or 3 issues?"

this Hot Extended cranking is both ridiculous and embarrassing, esp. given the status of this car and its restored condition

Negative, 30cc......I had my 69 electric fan wired exactly like you have, I thought it to be wise to have the engine cool/right temp even when off. 

I just purchased a clutch fan system for this 68 with the 302......

I dont think the fuel is "evaporating" out of the bowels, I just checked the car as its been sitting for 3 days due to weather conditions.  I pumped each bowel manually and the nozzles shot several times each.  Im beginning to believe the WOT hot start works because of AIR, not a fuel condition. 

So perhaps increasing primary curb idle and leaning out the mixture screws?  just a thought
 

Was wondering the same thing, but after it starts, it runs perfectly..

Its just the Hot starting thats an issue. Super strange

M1Mustang69 wrote:

Negative, 30cc......I had my 69 electric fan wired exactly like you have, I thought it to be wise to have the engine cool/right temp even when off. 

I just purchased a clutch fan system for this 68 with the 302......

I dont think the fuel is "evaporating" out of the bowels, I just checked the car as its been sitting for 3 days due to weather conditions.  I pumped each bowel manually and the nozzles shot several times each.  Im beginning to believe the WOT hot start works because of AIR, not a fuel condition. 

So perhaps increasing primary curb idle and leaning out the mixture screws?  just a thought
 

I feel that you need to perform all the checks and suggestions from the various posts with the engine in the hot condition where the problem occurs.  You have a PM.