whats up guys, i put a cam in my 350.its a mid 70s block.i lined up the crank dot at 12:00 and the cam sprocket dot at 6:00. put everything together car ran ok for the cam break in.after i start to drive it on the rd i would floor it or what ever it would sputter like crazy. i took of the timin chain with everything else. put it to TDC with #1 piston. lined up the dots again and the car runs alot better. but the car still sputters at 5000 rpm + , what could be the problem with this engine? i am very confused and angry. do u think i took off a lobe or 2? i broke two pushrods ,not at the same time though. could that caused the problem? the engine is carbed,the specs of the cam are 300\300 dur. and 515\515 lift. lunati braket master ll .at what position should i line up the dots on the sprokets? thanx for the help for the people that reply, i would like to do this sunday-monday since il have my days of then.
Dan

 

Yea the dots should be together. Sometimes you need to take a straight edge to double check.
It really sounds like your detonating cause your distributor timings is off.

What's your total timing set at ?

* plug vacuum advance port on carb...
* use dial back timing gun, or timing tape to show up to 40*.
* Check timing @ 3000, 4000. It really depends on your advance * springs, but for best performance use the loses springs, so total timing is all in at 3000rpms.
* For a Chevy 350, I would go with 36* total @ 3000 rpms.

....and replace all your push rods. I would

Ron

 

You have to ask, Why did the pushrods break? Is your valve train geometry correct? Sounds like it may not be, and high RMP is where it will tell.

~M~

 

you need the dots both straight up, or at 12:00, not dot to dot, and the #1 pistion @tdc and the rotor pointing to #1 on the cap. do you have the lash set right? that's what it sounds lik,e ot me. i build a 355 once with that cam and 1.6 rockers and dart heads and never had a problem. look at the valve train for any interferance problems.

 

ok so the dots should be strait up rite? both have to be at 12:00? i broke the pushrods cause i tightened the rockers to hard. o well il try it 1 more time this time with dots straight up. thanx guys

 

Whhhhhaaaattttt ???

 

...

 

now im confused. which way should the marks realy be alined? or is there to ways?

 

i went dot to dot

 

Both dots pointing AT EACH OTHER, crank dot at 12 o'clock and cam dot at 6 o'clock.

 

Actually it doesn't matter. Either way will time the cam to the crank. The cam turns at 1/2 speed of the crank. But the easy way is, cam dot @ 6o'clock and crank dot @ 12 o'clock.
If your breaking pushrods, you got problems. Check for interference in the valvetrain. Look for more bent pushrods. The high rpm sputtering could be valve float, lifter pump up, ignition or lack or fuel.

 

Ron

 

It doesn't matter if they are dot to dot, or both 12 o'clock. If they are dot to dot drop your distributor in pointing toward the #6 terminal on the cap, if they are aligned 12 and 12 o'clock, drop the distributor in pointing toward the #1 terminal on the cap.

Or. . . align them dot to dot just to make sure they are exactly correct, then turn the crankshaft exactly one revolution and drop the distributor in pointing toward the #1 terminal on the cap.

 

dot to dot will set your timing to fire on #6 which is strange to me so if you spin the crank so both dots are straight up it's easier to time at #1, for me, guess most of you like starting out on #6. maybe that's why we get all the threads on here about "why won't my car start after cam swap, or intake swap". people set it dot to dot like the manuals say then set the rotor to #1 and are 180* out. they fool with it a little, pull distributor reset the rotor and timing tab and by luck hit it after a time or two. i can't remember the last time i had to fight to get an engine to fire after i had it apart, and i bet i do more in a year then most of you will ever do.

 

That is exactly correct....just remember if the dots are:

12 and 6= #6 TDC

12 and 12= #1 TDC

For installation purposes, lining up the dots at 12 and 6 is much easier to see than trying to line them up at 12 and 12.