K88-79

Quick question, when installing a new cam (481 lift 280 dur) on a sbc 350 do the dots on the gears line up or do I retard or advance it?
Thank-you

HawkZ28

iTrader: (2)

Install it straight up. Not enough info on your combo to recommend otherwise. As a generalization, advancing moves the power lower, retarding moves it higher.

Don't forget to rotate then engine afterwards so both dots are in the 12:00 position. That way when you install the dizzy it's ready to go on cylinder one.

K88-79

Sb 350
Comp cam 481 lift 280 dur
flat top pistons
edelbrock performer intake
camel hump heads
q jet 750 I think..I thought it was a 650 but I was told they don't make 650 in q jet
if I point them both at 12:00 how can they line up? Sorry if I miss understood.
Thank-you

camaronewbie

line them up to get the cam degreed at ZERO advance on the cam. Afterward cam installed correctly, then rotate the engine so both dots are at 12 oclock and then the #1 cylinder will be TDC on compression stroke (is what I think he's saying - I never heard of this 12 oclock dots, but if I were any expert you'd be paying me right?

K88-79

Lol...thank-you

HawkZ28

iTrader: (2)

That's what I meant......posting from my phone so its hard for it to keep up with me...or maybe the other way around .

AFTER you've installed the cam with the dots lined up you rotate.

sofakingdom

iTrader: (1)

Both dots at 12:00 is correct...

Remember, there are 2 instances of #1 TDC during one complete engine cycle. Also, the #6 piston is always in exactly the same position as the #1. (they are 4 cyls away form each other in the firing order, exactly 1 full crank revolution) One instance of #1 TDC is #1 firing, and #6 end of exh stroke & beg of int stroke; the other instance of #1 TDC, those strokes are reversed.

#6 firing, and the exh/int changeover point for #1, occur when the dots are "dot to dot".

#1 firing, and the other point of #6, occur when the dots are both at 12:00.

You put the engine together at #6 firing, "dot to dot", because it's easier to see and line up right than the other; then you rotate the crank exactly 1 full turn, which rotates the cam exactly ½ turn, to put the dots both at 12:00 which #1 firing so you can line up the dist. Needless to say, if you line it up "dot to dot" and then put the dist in at #1, the engine will not run, but instead will spit back in the int or exh, or both, since both valves will be open a little bit on every cyl when it gets hit with a spark.

InfernalVortex

iTrader: (4)

Qjet will flow as mcuh as the engine needs up to 750 cfm, so you're good.

K88-79

thanks alot guys i always appreciate the help