got a la roller 360, edelbrock heads, , slapped a 780 v/s holley on that I had froma 440.. any ideas what I should have in it for a baseline jet ? something to start out at? is a 780 vacuum, secondary too much carb for this? eng is a 91 360 roller block, with a custom roller cam grind , don't know specs , I didn't intailly build it. airgap intake, rpm heads, headers, 3000 stall , 4;10 gears,
360, carb jetting recommendations
- Thread starter 68gtx
- Start date
-
MarzGraphixDesign
Well-Known Member
got to know the cam specs
fishy68
Tyr Fryr's Inc.
Not too much carb. Hard to overcarb with a vac secondary. Just run a tight enough vac secondary spring so it doesn't bog when you nail it and your good.
^^X2 on 72's and 76's to start^^ Idle vacuum will determine what power valve you need. Hard to guess that since you don't know the cam specs. When you get it running and the idle adjusted (in gear if it's an automatic) take a vac reading then use a PV that's 1/2~2/3 of that reading.
After you get those things done you can run it wide open (you need a fresh set of plugs) and have a look at the plugs to see what the jetting looks like. Abody is correct that the only way to get it right on is with a A/F meter but you can get it close if you know how to read plugs.
^^X2 on 72's and 76's to start^^ Idle vacuum will determine what power valve you need. Hard to guess that since you don't know the cam specs. When you get it running and the idle adjusted (in gear if it's an automatic) take a vac reading then use a PV that's 1/2~2/3 of that reading.
After you get those things done you can run it wide open (you need a fresh set of plugs) and have a look at the plugs to see what the jetting looks like. Abody is correct that the only way to get it right on is with a A/F meter but you can get it close if you know how to read plugs.
Serial # F 6946-05 Spec Card# 08485205Part # 20-000-9 CAMSHAFT, CRS CHRY 273-360 ROLLERCore C20-8C CAMSHAFT BLANK, CRS LONG NOSE/DRILLEDGrind # CRS 3162 /3162 HR110.0 DURATION @ .050 INTAKE 230 ROCKER ARM RATIOVALVE ADJ INTAKE .000 DURATION @ .050 EXHAUST 230 INTAKE 1.60VALVE ADJ EXHAUST .000 LOBE LIFT INTAKE .2850 EXHAUST 1.60VALVE LIFT INTAKE .456 LOBE LIFT EXHAUST .2850VALVE LIFT EXHAUST .456 LOBE SEPARATION 110.0DURATION .006 INTAKE C/L 106.0TAPPET LIFT INTAKE 292 CAM ADVANCE 4TAPPET LIFT EXHAUST 292 HYDRAULIC YVALVE TIMING .050 OVERHEAD CAM NVALVE OPEN INTAKE 9 JOURNAL DIAMETER STD 1.951VALVE OPEN EXHAUST 49 RECOMMENDED VALVE SPRINGSVALVE CLOSED INTAKE 41 DEPARTMENT PVALVE CLOSED EXHAUST 1
fishy68
Tyr Fryr's Inc.
Translated it's
230 degrees at .050" lift,=
292 gross duration
.456 lift
110 lobe center
Same starting recommendation on jets as earlier but start out with a 5.5" power valve. Once the idle mixture is adjusted take an idle vacuum reading (in drive with the brakes applied) and whatever it is use a power valve that's 60-65% of that reading. In other words if it idles at 9" of vacuum use a 5.5 valve. Then adjust the jets as needed to get a real light brown burn on the plugs.
If this is a new setup make sure and get the timing dialed in before you do much to the carb as timing drastically affects how fuel burns. With that cam and the low compression of a 91 360 I'd say you'll need a lot of initial timing, at least 19-20 degrees. It may even be able to handle more, just gotta watch that it doesn't kick back on the starter and damage it or the ring gear. 360's usually work well with 34 degrees total timing although yours has a pretty big cam for the compression so it may like a little more. 34 is a good starting point
-
