2X cams with 10.25-1 ?

My '79st;fresh top end last spring,1105,.395/.385,police exhaust,
just the first section of the 3 piece air box w/K&N
28 pumper stock main jet,110, up 1 on the needle and 17.5
Below 65° it will backfire through the carbs until warm = lean.
It needs a bigger main jet by one or two sizes.
But not having to clean a fowled plug sure is nice.

Roadflyer wrote: I know my compression tester reads a bit high, it actually read 210-210-230-210. The 230 is probably a loose valve clearance on #3. Do you think installing the 2X cams is worthwhile? or just pour the best pump gas I can find into it and jet a bit fat? What about carving static timing slots into the timing plate ( fixed electronic stock setup now) and tighter advance springs or lightening the advance weights?

Thank you for the info.
Don

Id say if anything the smaller cams will raise the cranking pressure depending on how theyre dialed in by not letting pressure out of cylinder.
Whats wrong with cams you have?

Intake Valve Closing point is the greatest contributing factor to trapped cylinder pressure.

Jetting is very dependent on carburetor fuel level being correct, especially on the low end circuits. It's really the very first thing you want to check and correct if it's out of spec.

Pretty much any of the OEM needle / needle jet combinations, of which there were many, will work with a 1 clip position raise on the needle when pods are used instead of an airbox. If you find you're having to drastically lift the needle in any situation with VM series carburetors, then fuel level is probably low.

Generally, when going from stock air box to pods with VM series carburetors in VM26 and later model VM28 carbs [not the early 900 28's] 5 size increases over stock main jet is a good starting point.