392/ 60 over/10.5 comp/ hyperutectics/ ansen rods/10/10 forged crank/850holley/525lift,304 adv dur.solid isky cam inst 2deg adv./727/ 4000 stall/430 spool/10.5x30 slicks/3200lb a body/electronic dist/6al/rev lim at7k/launch at 2500/ shift at 6000.103race gas.180 degree temp. DOES HORRIBLE.I AM BARELY INTO THE 13S.EVERYBODY TELLS ME MAX TIMING SHOULD BE NOT MORE THAN 20.IT LIKES 18 AT IDLE AND 32 AT 3000.I HAVE TAKEN SO MUCH TIMING OUT IT BARELY RUNS!DOES ANYONE HAVE ANY EXPERTISE ON THESE OLD HEMIS, TO KNOW IF MORE TIMING IS OK?
Total timing should be 15 at idle and 35 degrees total at 3000 rpm with the vac line off.
THANKYOU, THANKYOU, THANKYOU MARK.
No expert here, and I don't know the answers. But I do have a question: Why a 4000 rpm converter? That just seems super radical.
Don't know what gear he is running but I would think he needs every bit of a 4000 stall converter with the 850 carb and the 30" slicks, lets not forget the 304 duration cam @ .050. That is radical and probably hurting the vehicles bottom end performance. You want to go faster, get rid of the loppy cam, the slicks are likely to tall and the carb is way to big. Not sure what gear you have but here goes anyway, 4.10/4.30 with no more than a 28" tall slick. 750 HP DP holley carb. 240 max. duration at .050. If available I would even go with a 236 duration @ .050 with around .520/.530 lift. Those changes are worth at least 1/2 a second, probably a lot more with some carb tuning.
It looks like he's running a 4:30 with a spool. I was wondering the same thing myself. If he had enough convertor, and or rear gear.
Thank you for the input.MY APOLOGIES ON THE CAM SIZE. those specs were for the 452. the correct cam spec is an isky 505 with 254 dur@50 and 108 ls. installed 2deg advanced.this motor came from a 58 300 that had factory dual quads. my intake is a hot heads tunnel ram, single 4BBL plate and the 850dp.i am sure my max timing of 20deg was the issue.i took out the vacuum, blocked my mech advance to 16 deg on top of my initial of 15. my total adv is now 31/32. I will be running at atco nj this oct-6.I will keep you posted. Bob at hot heads says my peak power is 6,200 to 6,300.I will change my shift points also. DO YOU REALY THINK AN 850 IS THAT BIG? THANKS TO ALL FOR YOUR HELP. MARK
Yes an 850 is big, I struggled with one for yrs on a 440 before I ever got a decent time out of it. e.g. A friend of mine has been experimenting with carbs on his 10.6 second 408 Aspen. Thats 10.6 with a holley HP/DP 750. He bought a new 950 and the car slowed down half a second. He took it back to the so called pro who built it and swapped it for a 830DP. Again the car rain poorly, I believe 4 tenths slower than the 750. So ya, an 850 on a 392 is way to much. Its all about the velocity. Plus the duration is way to much 252 @ .050 is radical in my opinion. Certainly it will run better with the timing banged up 12 degrees. I am just saying it would run better with the right carb size, the right cam, and the right tire.. Instead of barely running 13's you should be well into the 12's with the light weight car. Good Luck Doc
DOC. I value your opinion, thank you. i will try both an 850 and 750. I will keep you posted. Mark.